WO2013179140A2

WO2013179140A2 - Optical rotation measuring device, optically rotational ingredient analyzing device, and optically rotational ingredient analyzing method

Info

Publication number: WO2013179140A2
Application number: PCT/IB2013/001512
Authority: WO
Inventors: Hiroshi Kajioka
Original assignee: GLOBAL FIBEROPTICS Ltd; Shionogi and Co Ltd
Current assignee: GLOBAL FIBEROPTICS Ltd; Shionogi and Co Ltd
Priority date: 2012-05-29
Filing date: 2013-05-29
Publication date: 2013-12-05
Anticipated expiration: 2014-11-29
Also published as: WO2013179140A3

Description

OPTICAL ROTATION MEASURING DEVICE, OPTICALLY ROTATIONAL INGREDIENT ANALYZING DEVICE, AND OPTICALLY ROTATIONAL

INGREDIENT ANALYZING METHOD TECHNICAL FIELD

[0001]

The present invention relates to an optically rotational ingredient analyzing device and an optically rotational ingredient analyzing method for analyzing with high precision the specific optical rotation of a substance with optical rotation, such as sugar solution, blood, or a living body. More specifically, the present invention relates to an optically rotational ingredient optically-analyzing device and method for measurement and analysis of the specific optical rotation, and temperature characteristics or wavelength characteristics of the specific optical rotation with high precision, and based thereon, analyzing concentration of the optically rotational ingredient contained in a specimen, and also relates to a wavelength characteristic measuring device for measurement of temperature characteristics of the optical rotation when the specimen is a light-scattering specimen, such as a living body. Furthermore, the present invention provides an improved part for use in the optically rotational ingredient analyzing device .

BACKGROUND ART

[0002]

There are three conventional main optical methods for measuring glucose concentration. The first method is a method of irradiating an infrared laser beam on a part of a living body, such as a finger, breaking down the scattered light from a blood vessel, and a living body etc., and non-invasively estimating glucose in the blood and a living body, as described in the following Patent Document 1. This method utilizes the fact that the scattered light decreases in proportion to the glucose concentration. This method has a problem that the light intensity of the scattered light is dependent on temperature, moisture, and oil component of skin etc., and therefore it is not currently widely used. [0003]

The second method is a method of making the polarized-light components which are orthogonal (perpendicular) to each other propagate through glucose, and then measuring birefringence and/or difference in the attenuation of the orthogonally polarized light components in an open loop, as described in the following Non-patent Document 1 and Patent Document 2, etc. However, according to this method, an error is as large as approximately 20% when 0.1 g/dL (deciliter) as a specimen, which is a healthy person's blood sugar level, is measured using an approximately 10 mm-long glucose-solution specimen contained in a case.

[0004]

That is, the first and the second method provide low precision detection of the specimen in which only a single optically rotational ingredient is contained, and are thus impossible to be implemented. Xt is still impossible to expect measurement of each optically rotational ingredient of the specimen in which multiple optically rotational ingredients are contained, or measurement of the same in the case where the specimen is a light-scattering specimen, such as a living body, and light transmission loss is very large.

[0005]

The third method is a method of measuring using the birefringence measuring device described in the following Patent Document 3. This method uses opposing nonreciprocal optical systems installed in a ring of an interferometer, places a specimen therein, and measures the specific optical rotation thereof using the phase measurement method of the optical fiber gyro disclosed in the following Non-Patent Document 2. This method allows measurement of a 10 mm-thick specimen, such as glucose with a concentration equivalent to 0.1 g/dL, which is a healthy person's blood sugar level, with sufficient measurement accuracy. However, even this method cannot separate and analyze concentration of each individual substance having optical rotatory in the case where the specimen is a light-scattering specimen, such as a living body, and optical transmission loss is very large, or in the case where multiple optical rotation ingredients are contained in the specimen. [0006]

Moreover, it is impossible for the first and the second method to expect reliable measurement of the specimen containing multiple kinds of optical rotation ingredients. That is, the conventional optical rotation characteristic measurement method could not measure concentration of an individual substance having optical rotatory when the specimen is a light-scattering specimen, such as living body, and optical transmission loss is very large, or when multiple substances having optical rotatory are contained in the specimen.

[0007]

Patent Document 1: JP 2004-313554

Patent Document 2: JP 2007-093289

Patent Document 3: JP 2005-274380

[0008]

Non-patent Document 1: Masayuki Yokota et al . , "Glucose sensor using a lead glass fiber polarization modulation device". The 31st Lightwave Sensing Technical Study Meeting LST31-8, PP. 51-56, August, 2003.

Non-patent Document 2: Kajioka and Oho, "Development of optical fiber gyro", The third Lightwave Sensing Technical Study Meeting, LST 3-9, PP. 55-62, June, 1989.

DISCLOSURE OF THE INVENTION

[0009]

An object of the present invention is to provide an optical rotation measuring device, an optically rotational ingredient analyzing device, and an optically rotational ingredient analyzing method for analyzing with high precision the specific optical rotation and ingredients contained in sugar solution, diluted blood, blood serum, exhaled breath condensate, a living tissue and a molecule etc.

[0010]

To solve the problem, the inventor carried out various experiments as described later, thereby leading to realization of the present invention. Embodiments of the present invention will be described in detail hereinafter.

To solve the problem, according to the first aspect of the present invention (hereinafter referred to as invention 1) , an optical rotation measuring device comprising: at least polarization maintaining optical fibers (which are referred to as PMFs hereafter) installed for an optical path for an optical signal, which are used for measurement of specific optical rotation of a specimen mounted on a specimen mounting portion and sandwich the specimen mounting portion, so as to form most of an optical loop path of a ring interferometer (which is referred to- as an optical ring path hereafter) for the optical signal; the specimen mounting portion; and polarized-light converting optical systems installed between the PMFs and the specimen mounting portion; wherein the optical rotation measuring device is configured so as to allow a clockwise and a counter-clockwise propagating optical signal, each propagating through the optical fiber portion in the optical ring path, to propagate through the PMFs in the same form of polarized light, and to propagate through the specimen in the forms of mutually orthogonal polarized lights; and the polarized-light converting optical systems, which face each other and sandwich the specimen, comprise: a polarization-rotation linearly polarizing module for rotating by 45 degrees a linearly polarized light propagating through the optical fiber portion in the optical ring path and outputting the resulting linearly polarized light, and a circularly polarizing module for outputting a left-handed or a right-handed circularly polarized light in accordance with a FAST axial mode or a SLOW axial mode of output polarization modes .

[0011]

According to the second aspect of the present invention (hereinafter referred to as invention 2) based on the invention 1, the optical rotation measuring device according to the invention 1 is characterized in that the circularly polarizing module has a configuration that a condenser lens, a circularly polarized light maintaining fiber, a single mode optical fiber (which is referred to as SMF hereafter) , and a lens are connected in series, and distance between the end part of the SMF and a surface of the lens on the side of facing the end part of the SMF is less than focal length of the lens.

[0012] According to the third aspect of the present invention (hereinafter referred to as invention 3) based on the invention 1 or 2, the optical rotation measuring device according to the invention 1 or 2 is characterized in that the circularly polarizing module has a configuration that a condenser lens, a circularly polarized light maintaining fiber, an SMF, and a lens are connected in series, at least one end part of the SMF on the side of facing the specimen is expanded-core or TEC (Thermally diffused Expanded Core) processed, and distance between the end part of the SMF and a surface of the lens on the side of facing the end part of the SMF is less than focal length of the lens.

[0013]

According to the fourth aspect of the present invention (hereinafter referred to as invention 4) based on any one of the inventions 1 to 3, the optical rotation measuring device according to any one of the inventions 1 to 3 is characterized in that the TEC processing subjected to at least the end part of the SMF constituting the circularly polarizing module on the side of facing the specimen, is to expand a core diameter 2 or 3 times larger than the original core diameter.

[0014]

According to the fifth aspect of the present invention (hereinafter referred to as invention 5) based on the invention 1, the optical rotation measuring device according to the invention 1 is characterized in that at least the end part of the SMF of the circularly polarizing module on the side of facing the specimen is expanded-core (TEC) processed, and a lens on the side of the specimen is not used.

[0015]

According to the sixth aspect of the present invention (hereinafter referred to as invention 6) , an optical rotation measuring device is characterized by comprising: at least PMFs installed for an optical path for an optical signal, which are used for measurement of specific optical rotation of a specimen mounted on a specimen mounting portion and sandwich the specimen mounting portion, so as to form most of an optical ring path of a ring interferometer for the optical signal; the specimen mounting portion; and polarized-light converting optical systems installed between the PMFs and the specimen mounting portion; wherein the optical rotation measuring device is configured so as to allow a clockwise and a counter-clockwise propagating optical signal, each propagating through the optical fiber portion in the optical ring path, to propagate through the PMFs in the same form of polarized light, and to propagate through the specimen in the forms of mutually orthogonal polarized lights; and the polarized-light converting optical systems use a polarization plane rotary element, which rotates the polarization plane of an optical signal by a predetermined angle either clockwise or counter-clockwise in the traveling direction of the optical signal when a polarized light beam enters one side of the polarization plane rotary element as the optical signal, and rotates in the reverse direction the polarization plane of an optical signal by a predetermined angle in the traveling direction of the optical signal when a polarized light beam enters the other side of the polarization plane rotary element as the optical signal, which is opposite to the case where a polarized light beam enters the one side of the polarization plane rotary element; and at least one end face of the PMFs on the side of facing the polarized-light converting optical systems is TEC processed. It is highly preferable that the predetermined angle is 45 degrees, thereby a detection sensibility becomes especially high and the device is easy to constitute (same hereafter) .

[0016]

According to the seventh aspect of the present invention (hereinafter referred to as invention 7) based on any one of the inventions 1 to 6, the optical rotation measuring device according to any one of the inventions 1 to 6 is characterized in that the polarization plane rotary element of the polarized-light converting optical systems uses a polarization plane rotary element, which rotates the polarization plane of an optical signal by 45 degrees either clockwise or counter-clockwise in the traveling direction of the optical signal when a linearly polarized light beam enters one side of the polarization plane rotary element as the optical signal, and rotates in the reverse direction the polarization plane of an optical signal by 45 degrees in the traveling direction of the optical signal when a linearly polarized light beam enters the other side of the polarization plane rotary element as the optical signal, which is opposite to the case where a linearly polarized light beam enters the one side of the polarization plane rotary element.

[0017]

According to the eighth aspect of the present invention (hereinafter referred to as invention 8) based on any one of the inventions 1 to 7, the optical rotation measuring device according to any one of the inventions 1 to 7 is characterized in that the optical rotation measuring device further comprises an optical rotation measuring system in which: an optical signal emitted from a light source is led to a first coupler, an in-line polarizer, and a second coupler, which are installed on an optical path; the second coupler branches the optical signal

directions through the PMFs that comprise most of an optical ring path and sandwich the specimen, and the branched optical signal propagates through the optical ring path; the optical signals propagated through the optical ring path are led to the specimen, which is placed on the optical ring path, from either side of the specimen via the polarized-light converting optical systems, which convert the optical signal to circularly polarized lights orthogonal to each other; the resulting transmitted lights are converted to be in the same mode as that of the linearly polarized lights output to the specimen, coupled to the PMFs which constitute the optical ring path, led to the second coupler and the in-line polarizer again, and led to a photodetector by the first coupler; and circular birefringence of the specimen is measured based on phase difference information of the optical signals propagated through the optical ring path clockwise and counter-clockwise; wherein the optical rotation measuring device further comprises a device for changing either or both temperature of the specimen and wavelength of the light source.

[0018]

According to the ninth aspect of the present invention (hereinafter referred to as invention 9) based on any one of the inventions 1 to 8, the optical rotation measuring device according to any one of the inventions 1 to 8 is characterized in that at least either one end part of the PMFs in the optical ring path on the side of facing the specimen or the other end part of the PMFs is detachably connected using an optical connector .

[0019]

According to the tenth aspect of the present invention (hereinafter referred to as invention 10) based on any one of the inventions 1 to 9, the optical rotation measuring device according to any one of the inventions 1 to 9 is characterized in that either one of the polarized-light converting optical systems, which face each other and sandwich the specimen, is installed on a movable linear guide, and the opposing polarized-light converting optical systems are opposing collimator optical systems, which keep optical coupling between polarized-light converting optical systems changes.

[0020]

According to the eleventh aspect of the present invention

(hereinafter referred to as invention 11) based on the invention 10, the optical rotation measuring device according to the invention 10 is characterized in that the specimen placed between a polarized-light converting collimator on the fixed side and a polarized-light converting collimator on the movable side is pinched by a forceps-like tool.

[0021]

According to the twelfth aspect of the present invention (hereinafter referred to as invention 12) based on the invention 11, the optical rotation measuring device . according to the invention 11 is characterized in that either one of the polarized-light converting optical systems, which face each other and sandwich the specimen, is installed on a fixed base, and the other one is installed on a movable base, and each of the polarized-light converting optical system on the fixed base and the polarized-light converting optical system on the movable base is installed facing a part of the forceps-like tool that pinches the specimen.

[0022] According to the thirteenth aspect of the present invention (hereinafter referred to as invention 13) based on the invention 11 or 12, the optical rotation measuring device according to the invention 11 or 12 is characterized in that the polarized-light converting collimator on the fixed base and the polarized-light converting collimator on the movable base, which are installed facing the part of the forceps-like tool that pinches the^■ specimen, are detaehably connected to an optical fiber, which comprises the optical ring path, using optical connectors.

[0023]

According to the fourteenth aspect of the present invention (hereinafter referred to as invention 14) based on any one of the inventions 1 to 13, the optical rotation measuring device is according to any one of the inventions 1 to 13 characterized in that wavelength of the light source is of a 1300 nm band when the specimen is a light-scattering specimen such as blood serum or a living body.

[0024]

To solve the problem, according to the fifteenth aspect of the present invention (hereinafter referred to as invention 15) , an optically rotational ingredient analyzing device is characterized by comprising: at least P Fs installed on an optical path for an optical signal, which are used for measurement of specific optical rotation of a specimen mounted on a specimen mounting portion and sandwich the specimen mounting portion, so as to form most of an optical ring path of a ring interferometer for the optical signal; the specimen mounting portion; and polarized-light converting optical systems installed between the PMFs and the specimen mounting portion; wherein the optically rotational ingredient analyzing device is configured so as to allow a clockwise and a counter-clockwise propagating optical signal, each propagating through the optical ring path, to propagate through the PMFs in the same form of polarized light, and to propagate through the specimen in the forms of mutually orthogonal polarized lights; and the optically rotational ingredient analyzing device further comprises at least either a wavelength changing device for changing wavelength of the optical signal, which is led to the specimen, or a temperature changing device for changing temperature of the specimen, and obtains information of optically rotational ingredients contained in the specimen based on the measurement results of change in phase difference information of the specimen, which is dependent on at least either wavelength change of the optical signal or temperature change of the specimen.

• [0025]

To solve the problem, according to the sixteenth aspect of the present invention (hereinafter referred to as invention 16) , an optically rotational ingredient analyzing device is characterized by comprising: at least PMFs installed for an optical path for an optical signal, which are used for measurement of specific optical rotation of a specimen mounted on a specimen mounting portion and sandwich the specimen mounting portion, so as to form most of an optical ring path of a ring interferometer for the optical signal; the specimen mounting portion; and polarized-light converting optical systems installed between the PMFs and the specimen mounting portion; wherein the optically rotational ingredient analyzing device is configured so as to allow a clockwise and a counter-clockwise propagating optical signal, each propagating through the optical fiber portion in the optical ring path, to propagate through the PMFs in the same form of polarized light, and to propagate through the specimen in the forms of mutually orthogonal polarized lights; and the polarized-light converting optical systems, which face each other and sandwich the specimen, comprise: an polarization-rotation linearly polarizing module for rotating by 45 degrees a linearly polarized light propagating through the optical ring path and outputting the resulting linearly polarized light, and a circularly polarizing module for outputting a left-handed or a right-handed circularly polarized light in accordance with a FAST axial mode or a SLOW axial mode of output polarization modes; and the optically rotational ingredient analyzing device further comprises at least either a wavelength changing device for changing wavelength of the optical signal, which is led to the specimen, or a temperature changing device for changing temperature of the specimen, and obtains information of optically rotational ingredients contained in the specimen based on the measurement results of change in phase difference information of the specimen, which is dependent on at least either wavelength change of the optical signal or temperature change of the specimen.

[0026]

According to the seventeenth aspect of the present ^•invention (hereinafter referred to as invention 17) based on the invention 15 or 16, the optically rotational ingredient analyzing device according to the invention 15 or 16 is characterized in that the circularly polarizing module has a configuration that a circularly polarized light maintaining fiber, an SMF, and a lens are connected in series, and distance between the end part of the SMF and a surface of the lens on the side of facing the end part of the SMF is less than focal length of the lens.

[0027]

According to the eighteenth aspect of the present invention (hereinafter referred to as invention 18) based on the invention 17, the optically rotational ingredient analyzing device is characterized in that the circularly polarizing module has a configuration that a circularly polarized light maintaining fiber, an SMF, and a lens are connected in series, at least one end part of the SMF on the side of facing the specimen is expanded-core or TEC processed, and distance between the end part of the SMF and a surface of the lens on the side of facing the end part of the SMF is less than focal length of the lens.

[0028]

According to the nineteenth aspect of the present invention (hereinafter referred to as invention 19) based on the invention 15 or 16, the optically rotational ingredient analyzing device according to the invention 15 or 16 is characterized in that the TEC processing subjected to at least the end part of the SMF constituting the circularly polarizing module on the side of facing the specimen, is to expand a core diameter 2 or 3 times larger than the original core diameter.

[0029]

According to the twentieth aspect of the present invention (hereinafter referred to as invention 20) based on the invention 15 or 16, the optically rotational ingredient analyzing device according to the invention 15 or 16 is characterized in that at least the end part of the SMF of the circularly polarizing module on the side of facing the specimen is expanded-core (TEC) processed, and a lens on the side of the specimen is not used.

[0030]

To solve the problem, according to the twenty-first aspect of the present invention (hereinafter referred to as invention 21) , an optically rotational ingredient analyzing device is characterized by comprising: at least PMFs installed on an optical path for an optical signal, which are used for measurement of optically rotational ingredient of a specimen mounted on a specimen mounting portion and sandwich the specimen mounting portion, so as to form most of an optical ring path of a ring interferometer for the optical signal; the specimen mounting portion; and polarized-light converting optical systems installed between the PMFs and the specimen mounting portion; wherein the optical rotation analyzing device is configured so as to allow a clockwise and a counter-clockwise propagating optical signal, each propagating through the optical fiber portion in the optical ring path, to propagate through the PMFs in the same form of polarized light, and to propagate through the specimen in the forms of mutually orthogonal polarized lights; and the polarized-light converting optical systems use a polarization plane rotary element, which rotates the polarization plane of an optical signal by 45 degrees either clockwise or counter-clockwise in the traveling direction of the optical signal when a polarized light beam enters one side of the polarization plane rotary element as the optical signal, and rotates in the reverse direction the polarization plane of an optical signal by 45 degrees in the traveling direction of the optical signal when a polarized light beam enters the other side of the polarization plane rotary element as the optical signal, which is opposite to the case where a polarized light beam enters the one side of the polarization plane rotary element; and at least one end face of the PMFs on the side of facing the polarized-light converting optical systems is TEC processed; and the optically rotational ingredient analyzing device further comprises at least either a wavelength changing device for changing wavelength of the optical signal, which is led to the specimen, or a temperature changing device for changing temperature of the specimen, and obtains information of optically rotational ingredients contained in the specimen based on the measurement results of change in phase difference information of the specimen, which is dependent on at least- either wavelength change of the optical signal or temperature change of the specimen.

[0031]

According to the twenty-second aspect of the present invention (hereinafter referred to as invention 22) based on any one of the inventions 15 to 21, the optically rotational ingredient analyzing device according to any one of the inventions 15 to 21 is characterized in that the optically rotational analyzing device further comprises an optical rotation measuring system in which: an optical signal emitted from a light source is led to a first coupler, an in-line polarizer, and a second coupler, which are installed on an optical path; the second coupler branches the optical signal into two linearly polarized lights, which propagate in both directions through the PMFs that comprise an optical ring path and sandwich the specimen, and the branched optical signal propagates through the optical ring path; the optical signals propagated through the optical ring path are led to the specimen, which is placed on the optical ring path, from either side of the specimen via the polarized-light converting optical systems, which convert the optical signal to circularly polarized lights orthogonal to each other; the resulting transmitted lights are converted to be in the same mode as that of the linearly polarized lights output to the specimen, coupled to the PMFs which constitute the optical ring path, led to the second coupler and the in-line polarizer again, and led to a photodetector by the first coupler; and circular birefringence of the specimen is measured based on phase difference information of the optical signals propagated through the optical ring path clockwise and counter-clockwise .

[0032] According to the twenty-third aspect of the present invention (hereinafter referred to as invention 23) based on any one of the inventions 15 to 22, the optically rotational ingredient analyzing device according to any one of the inventions 15 to 22 is characterized in that at least either one end part of the PMFs in the optical ring path on the side of facing the specimen or the other end part of the PMFs is detachably connected using an optical connector.

[0033]

According to the twenty-fourth aspect of the present invention (hereinafter referred to as invention 24) based on any one of the inventions 15 to 23, the optically rotational ingredient analyzing device according to any one of the inventions 15 to 23 is characterized in that either one of the polarized-light converting optical systems, which face each other and sandwich the specimen, is installed on a movable linear guide, and the opposing polarized-light converting optical systems are opposing collimator optical systems, which keep optical coupling between the PMFs even if the distance between both of the opposing polarized-light converting optical systems changes.

[0034]

According to the twenty-fifth aspect of the present invention (hereinafter referred to as invention 25) based on any one of the inventions 15 to 24, the optically rotational ingredient analyzing device according to any one of the inventions 15 to 24 is characterized in that the specimen placed between a polarized-light converting collimator on the fixed side and a polarized-light converting collimator on the movable side is pinched by a forceps-like tool.

[0035]

According to the twenty-sixth aspect of the present invention (hereinafter referred to as invention 26) based on the invention 25, the optically rotational ingredient analyzing device according to the invention 25 is characterized in that either one of the polarized-light converting optical systems, which face each other and sandwich the specimen, is installed on a fixed base, and the other one is installed on a movable base, and each of the polarized-light converting optical system on the fixed base and the polarized-light converting optical system on the movable base is installed facing a part of the forceps-like tool that pinches the specimen.

[0036]

According to the twenty-seventh aspect of the present invention (hereinafter referred to as invention 27) based on the invention 25 or 26, the optically rotational ingredient analyzing device according to the invention 25 or 26 is characterized in that the polarized-light converting collimator on the fixed base and the polarized-light converting collimator on the movable base, which are installed facing the part of the forceps-like tool that pinches the specimen, are detachably connected to an optical fiber, which comprises the optical ring path, using an optical connector.

[0037]

According to the twenty-eighth aspect of the present invention (hereinafter referred to as invention 28) based on any one of the inventions 15 to 27, the optically rotational ingredient analyzing device is characterized in that the optical rotation of the specimen is measured while changing the temperature of the specimen or changing the wavelength of the light source, or changing both the temperature and the wavelength at N points, and solving N-dimensional simultaneous linear equations and finding ingredient concentration of N kinds of substances having optical rotatory contained in the specimen where N denotes an integer.

[0038]

According to the twenty-ninth aspect of the present invention (hereinafter referred to as invention 29) based on any one of the inventions 15 to 28, the optically rotational ingredient analyzing device according to any one of the inventions 15 to 28 is characterized in that the optically rotational ingredient analyzing device determines ingredient concentration of N kinds of substances having optical rotatory contained in the specimen using a corresponding table, which allows identification of a corresponding relationship between information of change in temperature of the specimen, change in wavelength of the light source, or information of both of these changes, and at least one of change in the optical rotation of the specimen, the optically rotational ingredient, and concentration of the optically rotational ingredient.

[0039]

According to the thirtieth aspect of the present invention (hereinafter referred to as invention 30) based on any one of the inventions 15 to 28, the optically rotational ingredient analyzing device according to any one of the inventions 15 to 29 is characterized in that wavelength of the light source is of a 1300 nm band when the specimen is a light-scattering specimen such as blood serum or a living body.

[0040]

To solve the problem, according to the thirty-first aspect of the present invention (hereinafter referred to as invention 31) , an optically rotational ingredient analyzing method using an optical fiber ring interferometer is characterized by comprising the steps of: preparing an optical ring path, which comprises an optical path constituted mainly by PMFs sandwiching a specimen and polarized-light converting optical systems that are inserted facing each other and sandwiching a specimen; preparing either a means for changing temperature of the specimen or a means for changing wavelength of a light source, or both of these means; transmitting an optical signal in both directions in the same mode through the PMFs along the optical path, and making circularly polarized lights orthogonal to each other enter the specimen in the either of the directions towards the specimen by polarized-light converting optical systems; preparing a polarization-rotation linearly polarizing module and a circularly polarizing module as the polarized-light converting optical systems; and preparing a polarization plane rotary element for the polarization-rotation linearly polarizing module, which rotates the polarization plane of an optical signal by 45 degrees either clockwise or counter-clockwise in the traveling direction of the optical signal when a polarized light beam enters one side of the polarization plane rotary element as the optical signal, and rotates in the reverse direction the polarization plane of an optical signal by 45 degrees in the traveling direction of the optical signal when a polarized light beam enters the other side of the polarization plane rotary element as the optical signal, which is opposite to the case where a polarized light beam enters the one side of the polarization plane rotary element; wherein the interferometer comprises the step of obtaining information of optically rotational ingredients contained in the specimen based on the measurement results of change in phase difference information of the specimen, which is dependent on at least either wavelength change of the optical signal or temperature change of the specimen.

[0041]

According to the thirty-second aspect of the present invention (hereinafter referred to as invention 32) based on the invention 31, the optically rotational ingredient analyzing method according to the invention 31 is characterized by further comprising the steps of: connecting a circularly polarized light maintaining fiber, an SMF, and a lens in series to form the circularly polarizing module; and maintaining a distance between the end part of the SMF and a surface of the lens on the side of facing the end part of the SMF to be less than focal length of the lens.

[0042]

According to the thirty-third aspect of the present invention (hereinafter referred to as invention 33) based on the invention 31 or 32, the optically rotational ingredient analyzing method according to the invention 31 or 32 is characterized by further comprising the steps of: configuring the circularly polarizing module where a circularly polarized light maintaining fiber, an SMF, and a lens are connected in series, preparing at least one end part of the SMF on the side of facing the specimen is expanded-core or TEC processed, and arranging distance between the end part of the SMF and the surface of the lens on the side of facing the end part of the SMF being less than focal length of the lens.

[0043]

According to the thirty-fourth aspect of the present invention (hereinafter referred to as invention 34) based on the invention 31, the optically rotational ingredient analyzing method is characterized by comprising the step of: preparing the circularly polarizing module in which, at the ends of the module, an end part of the SMF is expanded-core (TEC) processed; wherein a lens on the side of the specimen is not used.

[0044]

To solve the problem, according to the thirty-fifth aspect of the present invention (hereinafter referred to as invention 35), an optically rotational ingredient analyzing method is characterized by comprising the steps of: preparing an optically rotational ingredient analyzing system having at least PMFs installed on an optical path for an optical signal, which are used for measurement of optically rotational ingredient of a specimen mounted on a specimen mounting portion and sandwich the specimen mounting portion, so as to form an optical ring path of a ring interferometer for the optical signal; the specimen mounting portion; and polarized-light converting optical systems installed between the PMFs and the specimen mounting portion; and polarized-light converting optical systems installed between the PMFs and the specimen mounting portion; configuring the optically rotational ingredient analyzing system so as for the optical signal each propagating through the optical ring path clockwise and counter-clockwise, to propagate through the PMFs in the same form of polarized light, and to propagate through the specimen in the forms of mutually orthogonal polarized lights; preparing a polarization plane rotary element in the polarized-light converting optical systems, which rotates the polarization plane of an optical signal by 45 degrees either clockwise or counter-clockwise in the traveling direction of the optical signal when a polarized light beam enters one side of the polarization plane rotary element as the optical signal, and rotates in the reverse direction the polarization plane of an optical signal by 45 degrees in the traveling direction of the optical signal when a polarized light beam enters the other side of the polarization plane rotary element as the optical signal, which is opposite to the case where a polarized light beam enters the one side of the polarization plane rotary element; preparing PMFs where at least one end face of the PMFs is TEC processed on the side of facing the polarized-light converting optical systems, preparing at least either a wavelength changing device for changing wavelength of the optical signal, which is led to the specimen, or a temperature changing device for changing temperature of the specimen; and obtaining information of optically rotational ingredients contained in the specimen based on the measurement results of change in phase difference information of the specimen, which is dependent on at least either wavelength change of the optical signal or temperature change of the specimen.

[0045]

According to the thirty-sixth aspect of the present invention (hereinafter referred to as invention 36) based on any one of the inventions 31 to 35, the optically rotational ingredient analyzing method according to any one of the inventions 31 to 35 is characterized by further comprising the steps of: preparing N different requirements for either temperature of the specimen or wavelength of the light source, or for both the temperature and the wavelength; and solving -dimensional simultaneous linear equations based on the results and finding ingredient concentration of N kinds of substances having optical rotatory contained in the specimen where N denotes an integer.

[0046]

According to the thirty-seventh aspect of the present invention (hereinafter referred to as invention 37) based on any one of the inventions 31 to 36, the optically rotational ingredient analyzing method according to any one of the inventions 31 to 36 is characterized by further comprising the steps of: installing on a movable linear guide either one of the polarized-light converting optical systems, which face each other sandwiching the specimen; and keeping optical coupling between the PMFs in the opposing polarized-light converting optical systems even if the distance between both of the polarized-light converting optical systems changes.

[0047]

According to the thirty-eighth aspect of the present invention (hereinafter referred to as invention 38) based on any one of the inventions 31 to 37, the optically rotational ingredient analyzing method according to any one of the inventions 31 to 37 is characterized by further comprising the step of: preparing a forceps-like tool in which the polarized-light converting optical system on the fixed side and the polarized-light converting optical system on the movable side are installed.

[0048]

According to the thirty-ninth aspect of the present invention (hereinafter referred to as invention 39) based on the invention 38, the optically rotational ingredient analyzing method according to the invention 38 is characterized by further comprising the step of: preparing the forceps-like tool detachably connected using an optical connector.

[0049]

According to the fortieth aspect of the present invention (hereinafter referred to as invention 40) based on any one of the inventions 31 to 39, the optically rotational ingredient analyzing method according to any one of the inventions 31 to 39 is characterized by further comprising the step of: preparing P Fs where an optical connector is connected to at least one end part of the PMFs.

[0050]

According to the forty-first aspect of the present invention (hereinafter referred to as invention 41) based on any one of the inventions 31 to 40, the optically rotational ingredient analyzing method according to any one of the inventions 31 to 40 is characterized by further comprising the step of: preparing a light source where wavelength of the light source is of a 1300 nm band when the specimen is a light-scattering specimen such as blood serum or a living body.

Effects of the Invention

[0051]

The present invention measures the specific optical rotation and analyzes the optically rotational ingredients of glucose contained in sugar solution, diluted blood, blood serum, exhaled breath condensate, a living tissue and a molecule thereof etc. and other subjects having optical rotatory with high precision.

BRIEF DESCRIPTION OF DRAWINGS

[0052] Fig. 1 is a block diagram of an optical system of an optical rotation measuring method according to an embodiment of the present invention;

Fig.2 is a view explaining a configuration of a polarized-light converting optical system used in an embodiment, according to the present invention;

Fig. 3 is a view explaining a configuration of a polarized-light converting optical system used in an embodiment of the present invention;

Fig. 4 is a block diagram of an opposing circularly polarizing module with variable gap used in an embodiment according to the present invention;

Fig. 5 illustrates an entire configuration of optical rotation measurement and an optically rotational ingredient analyzing device using a forceps-like tool, according to an embodiment of the present invention;

Fig. 6 is a block diagram of another optical system of an optical rotation measuring method, according to an embodiment of the present invention; and

Fig. 7 is a block diagram of an optical system of a conventional optical rotation measuring method.

DESCRIPTION OF EMBODIMENTS

[0053]

An embodiment of the present invention is explained with reference to drawings hereafter. Note that each drawing used for explanation of the outline of dimensions, form, arrangement etc. of each constituent element is schematically illustrated to such an extent that the embodiment of the present invention is understandable. For the convenience of description of the present invention, a part of the drawings may be drawn with a different enlargement ratio. Moreover, some drawings used for explanation of an embodiment of the present invention may not be analogous to an actual object and/or description of the embodiment. The same reference numeral is attached to the same constituent elements in each drawing for avoiding redundant explanation. Moreover, in description of the present invention, explanation of a device for measuring temperature characteristics and wavelength characteristics of the optical rotation may serve as those of an optical rotation measuring device, an optically rotational ingredient analyzing device, an optically rotational ingredient analyzing method etc. for a substance having optical rotatory. That is, those explanations include many redundant portions. To avoid redundancy of explanation, description of the optical rotation measuring device may serve as those of the optically rotational ingredient analyzing device and the optically rotational ingredient analyzing method for the substance having optical rotatory, with keeping those explanations from being misunderstood without particular notice to the effect, or vice versa .

[0054]

Fig. 7 is a block diagram of an optical system of a conventional optical rotation measuring method. In Fig. 7, on an optical path of an optical signal emitted from an SLD ( super-luminescent diode) light source 1, an optical signal emitted from a light source 1 is branched by a first coupler 2-1, and led to a fiber-type in-line polarizer 3 and linearly polarized in there. It is then branched by a second coupler 2-2 to polarization maintaining optical fibers (PMFs) 4-1 and 4-2 which constitute an optical loop path of a ring optical interferometer (hereinafter referred to as an optical ring path or just a ring) . The optical signal branched to the PMF 4-1 is led, as a right-handed (or a left-handed) circularly polarized light, to a specimen 11 mounted on a specimen mounting portion (not shown in the drawing) through the optical path via a phase modulator 5 and a polarized-light converting optical system 7-1, which is constituted by a lens 6-1, a polarizer 8-1, a Faraday element 9-1, and a 1/4 wave plate 10-1. On the other hand, the optical signal branched to the PMF 4-2 is led, as a left-handed (or a right-handed) circularly polarized light, to the specimen 11 through the optical path via a PMF 4-3 wound into a coil shape, and a polarized-light converting optical system 7-2 constituted by a lens 6-2, a polarizer 8-2, a Faraday element 9-2, and a 1/4 wave plate 10-2. The light source 1 of Fig. 7 has adopted SLD of a 1300 nm band.

[0055]

The circularly polarized lights that have propagated through the specimen 11 in both directions are returned to the original linearly polarized light by the polarized-light converting optical systems 7-1 and 7-2, and propagate through the PMFs 4-1 and 4-2 in the direction opposite to the direction when they have entered the specimen 11. It is then interfered at the coupler 2-2 and led to a photodetector 12 via the polarizer 3 and the first coupler 2-1. Afterwards, a signal processing circuit 13 detects and outputs an electrical signal proportional to the phase difference between the optical signals, which propagated through the optical ring path in both directions. The signal processing method in this case uses a method based on the Non-patent Document 2. A phase modulation signal 14 is a sinusoidal signal of approximately 20 kHz. Note that the coupler 2-1 may be replaced with an optical circulator. Both a 2x2 coupler and a dual stage optical circulator are used in the experiment, and the latter is approximately 3dB lower

1

[0056]

A PZT (Lead Titanate Zirconate) piezoelectric element wound with an approximately 1 m-long optical fiber is used as the phase modulator 5. This modulator is modulated by a sinusoidal modulating signal 14 with a resonance frequency of 20 kHz output from the signal processing circuit 13. The optical fiber gyro given in Non-patent Document 2 is a system in which a modulator is modulated by a sinusoidal wave, and a photodetector detects the fundamental harmonic, the second order harmonic, and the fourth order harmonic. The phase difference is controlled to be a fixed value according to arctangent (tan^-1) of the amplitude ratio of the fundamental harmonic to the second order harmonic, and the modulation factor is controlled to be a fixed value according to the ratio of the second order harmonic to the fourth order harmonic. If a specimen is an optical rotatory material, phase difference will occur between the left-handed and right-handed circularly polarized lights, and it will be detected by the signal processing circuit 13 using the ring interferometer principle.

[0057]

When there is no specimen, the optical fiber gyro may measure the earth's rotation angular velocity. In this case, phase difference, which can be calculated by multiplication of the scale factor decided dependent on the ring fiber length, wavelength, and radius of the fiber ring by the earth' s rotation angular velocity, occurs. Since phase difference twice as large as the earth's rotation angular velocity may be measured by flipping vertically the ring fiber plane, it is possible to calibrate the absolute value of output phase difference of an optical interferometer.

[0058]

While RS232C interface is used as an electric output interface of a prototype of the signal processing circuit 13, a USB may be used for outputting when a commercially available converter is used. Note that it is well-known that if a specimen has an optical rotation of Φ degrees, phase difference of 2Φ between the optical signals, which propagate the ring clockwise and counter-clockwise will develop.

[0059]

In the conventional optical system for optical rotation measurement of Fig. 7, lights collimated by lenses 6-1 and 6-2 propagate through the specimen 11. In this case, when the specimen is a liquid with small light transmission loss, such as glucose, the specific optical rotation can be measured successfully. However, in the case of a part of the living body, such as a finger or diluted blood, the light receiving level is considerably low due to the scattering loss of the specimen, and thus measurement of the specific optical rotation with sufficient precision is impossible. For example, when the specimen is the webbing between the root of the thumb and the index finger, and is 1 mm in length, and a 1300 nm-band PANDA typed PMF (referred to as PM1300 hereafter) made by Fujikura is used as the PMFs 4-1 and 4-2, insertion loss of the fibers in the opposing polarized-light converting optical systems 7-1 and 7-2 is as large as 45 dB; wherein an aspheric lens of 0.7 mm in focal distance is used for the lens. Total loss including the polarizers, the couplers, the ring PMFs etc. in Fig. 7 is as large as 51 dB, output of the SLD light source 1 is 20 mW (13 dBm) , and the optical level received by the photodetector 12 is -38 dBm.

[0060] A healthy person' s blood sugar level is approximately 100 mg/dL, and when linearly polarized light propagates through a 1 mm-thick living body, optical rotation of approximately 0.0005 degrees will generate. It is equivalent to phase difference of approximately 0.0005 degrees when converted to the phase difference between the clockwise and the counter-clockwise optical signals in the optical rotation measuring optical-system in Fig .7. Generally, it is well-known that linearly polarized light can be resolved into the left-handed and right-handed circularly polarized lights, and phase difference between the left-handed and right-handed circularly polarized lights is 2Θ as described above, when an optical rotation angle is Θ. However, phase difference between circularly polarized lights, which propagate through a ring optical interferometer clockwise and counter-clockwise, becomes Θ . In an experiment according to the present invention, a required light receiving level for measurement of the phase difference in a 0.0005 degree level between the circularly polarized lights propagating through the ring clockwise and counter-clockwise with precision of 10% is -27 dBm (2 μϊί) . Therefore, the conventional optical system of Fig. 7 is unable to measure the specific optical rotation of a living body non-invasively, if it remains unchanged.

[0061]

It is well-known that it is very difficult to estimate the blood sugar level of a living body non-invasively. Many developers were challenged to measure blood sugar level non-invasively and proposed many developments . However, since it was a really difficult problem, measurement precision was insufficient, and estimation of blood sugar level of a living body was impossible but measurement of sugar content in fruit etc. There was no choice but to abandon the developments. However, only the present inventor has overcome the problem. Therefore, it has been considered impossible to solve the problem that should be solved by the present invention and has been given up even to challenge.

[0062]

However, the inventor has studied various different ways to solve the problem. Notably, the inventor has studied following three methods as a means of sharply reducing the optical transmission loss of the living body with a large light scattering loss. The first method is an optical connecting method for a living body using TEC (Thermally diffused Expanded Core) processing of an optical fiber end part. The second method is optimization of a beam size (or a beam waist BW) in a living body. The third method is to improve the way to grip a living body. As a result, in the ease where temperature characteristics of a substance having optical rotatory and/or wavelength characteristics of an optical signal differ due to types of ingredients of the substance with optical rotation, a polarized-light converting optical system using a polarization plane rotary element is adopted, thereby allowing ingredient analysis of the substance having optical rotatory included in the specimen.

[0063]

A polarized-light converting optical system used for an optical rotation measuring device, according to an embodiment of the present invention, is explained below. According to a preferable working example of an embodiment of the present invention, to improve a specific optical rotation measuring precision of a specific optical rotation measuring device and an optically rotational ingredient analyzing precision of an optically rotational ingredient analyzing device, a polarization plane rotary element used in the polarized-light converting optical system rotates the polarization plane of an optical signal by a predetermined angle either clockwise or counter-clockwise in the traveling direction of the optical signal when a polarized light beam enters one side of the polarization plane rotary element as the optical signal, and rotates in the reverse direction the polarization plane of an optical signal by a predetermined angle in the traveling direction of the optical signal when a polarized light beam enters the other side of the polarization plane rotary element as the optical signal, which is opposite to the case where a polarized light beam enters the one side of the polarization plane rotary element.

[0064]

An embodiment of the present invention is explained concretely below. Fig.1 is a block diagram of an optical system of an optical rotation measuring method according to an embodiment of the present invention. The polarized-light converting optical systems 7-1 and 7-2 of Fig. 7 are divided into polarization-rotation linearly polarizing modules 15-1 and 15-2 and circularly polarizing modules 16-1 and 16-2.

[0065]

Figs. 2 and 3 are views explaining concrete examples of a configuration of the polarization-rotation linearly polarizing modules 15-1 and 15-2 and circularly polarizing modules 16-1 and 16-2 used in this embodiment of the present invention. Reference numerals 4-1 and 4-2 denote 1300 nm band PANDA typed polarization-maintaining optical fibers: PM1300, which oppose to each other and are installed on either side of a specimen 11, respectively. Reference numerals 6-1 to 6-6 denote a lens, respectively. Optical connectors 17-1 and 17-2 are attached to the end part of the PMFs 4-1 and 4-2, respectively As shown in the figures, linearly polarized lights emitted from the PMFs 4-1 and 4-2 using the PM1300 are collimated by the lenses 6-1 and 6-2, penetrate polarizers 8-3 and 8-4 and Faraday elements 9-3 and 9-4, which are polarization plane rotary elements, and are coupled to circularly polarizing fibers 19-1 and 19-2 by the lenses 6-3 and 6-5. That is, the 1300 nm band PANDA typed PMFs 4-1 and 4-2 are connected to the circularly polarizing fibers 19-1 and 19-2 and single mode optical fibers (referred to as SMF hereafter) 20-1 and 20-2 via the lenses 6-3 and 6-5 for collimation, and the propagated optical signals enter the specimen 11 via the lenses 6-4 and 6-6 for collimation. Reference numerals 18-1 and 18-2 are magnets for the Faraday elements. The circularly polarizing fibers are a circularly polarized light maintaining optical fiber, which output a left-handed and a right-handed circularly polarized light, respectively, corresponding to intrinsic polarization direction for incident linearly polarized light. For example, they are available from Chiral Photonics, Inc.

[0066]

In Figs. 2 and 3, end parts 21-1 and 21-2 of the SMFs 20-1 and 20-2 at the ends of the circularly polarizing modules 16-1 and 16-2 are TEC fibers with core diameter of 3 times the original diameter. The experiment showed that the loss of the opposing collimators using the regular PM1300 is 45 dB, as described above. However, loss of the opposing collimators using the TEC fibers with the core diameter of 3 times the original diameter is 30 dB, which is 15 dB less. An aspheric lens of 0.7 mm in focal distance is also used in this case.

[0067]

Therefore, total loss including · the polarizer, the couplers, the ring PMFs etc. in Fig. 1, is approximately 40 dB, and light receiving level is -27 dBm, which allows measurement of the specific optical rotation of a living body. Since living body insertion loss of the TEC fiber with a twofold or threefold core diameter without lenses is approximately 35 dB for a 1 mm-thick living body, use of a higher outputting light source and/or longer measuring time allows omission of the lenses . The TEC processing for making a core diameter two or three times larger than the original core diameter contributes greatly to reduction of loss. If it is less than twofold, the loss becomes larger, and processing to make more than threefold is impossible.

[0068]

Moreover, a configuration of using regular single mode optical fibers with a regular sized core, such as SM28 made by Corning, Inc. as the SMFs 20-1 and 20-2 at the end parts of the circularly polarizing modules 16-1 and 16-2 in Figs. 2 and 3 and making those end parts approach the corresponding lenses as close as possible allows decrease in the living body insertion loss. The configuration is required to have a combination of multiple lenses in this case.

[0069]

Detailed explanation will be given using Figs .1 to 3 below. When light in SLOW axial mode of the PANDA typed PMF 4-1 enters the circularly polarized light maintaining optical fiber 19-1, right-handed circularly polarized light is emitted from the circularly polarizing module 16-1, thereby entering the specimen. The right-handed circularly polarized light that has propagated the specimen and then entered the circularly polarizing module 16-2 is output in the FAST axial mode from the circularly polarizing module 16-2. In the same manner, with respect to polarized light propagating in the counter direction, when the light in the FAST axial mode of the PANDA typed PMF 4-2 enters the circularly polarizing module 16-2, the circularly polarizing module 16-2 then outputs left-handed circularly polarized light, which then enters the specimen. The left-handed circularly polarized light that has propagated through the specimen and entered the circularly polarizing module 16-1 is output in the SLOW axial mode- from the circularly polarizing module 16-1. Lights propagating through the PMFs 4-1 and 4-2, respectively, may be in the same polarization mode by installing the Faraday elements 9-3 and 9-4 such that the polarization plane is made to rotate 45 degrees in the opposite direction with each other in the traveling direction of the optical signal.

'[0070]

Fig. 4 is a block diagram of an opposing circularly polarizing module with a variable gap between the polarized-light converting optical systems 7-1 and 7-2 used in an embodiment according to the present invention. The circularly polarizing modules 16-1 and 16-2 are installed on a fixed base 22-1 facing each other and sandwiching the specimen 11. The specimen 11 is installed in a temperature controller 24. The temperature controller 24 or temperature controlled bath has windows on both sides, which allow an optical signal to pass through on either side. While a small temperature controller CTC500 made by OPTQUEST Co. Ltd. is used in the embodiment, a cell-like specimen may be equipped with a heater alternatively, so as to change the temperature . The circularly polarizing module 16-1 is mounted on a fixed base 22-2, and the movable circularly polarizing module 16-2 is mounted on a movable linear guide 23. Optical axis adjustment in this optical system is performed so that coupling of PMFs 4-1 and 4-2 must be maintained even if the movable circularly polarizing module 16-2 mounted on the linear guide is moved towards the circularly polarizing module 16-1.

[0071]

Fig. 5 illustrates an entire configuration for specific optical rotation measurement and an optically rotational ingredient analyzing device for a living body using a forceps-like tool 26, according to an embodiment of the present invention. The tip end of the forceps-like tool 26 in Fig. 5 is equipped with miniaturized circularly polarizing modules 16-1 and 16-2, and with such a configuration, optical axis adjustment is performed so that coupling of PMFs 4-1 and 4-2 may be maintained even if the gap changes. Reference numeral 25 in Fig. 5 denotes an optical interferometer other than a polarized-light converting optical system,- according to the present invention. Moreover, the optical interferometer 25 is connected to the PMFs 4-1 and 4-2 via an optical connector. A refractive index matching material is used on the interface between the living body and each of the circularly polarizing modules. A refractive index matching sheet may be used instead of the index matching material. With such a configuration, attachment and detachment of the forceps-like tool 26 may be possible, thereby improving usability.

[0072]

Next, optimization of a beam size (or a beam waist BW) in a living body as the second improvement method will be explained. When a light propagates through a living body, it may be influenced by absorption and scattering. Influence of scattering becomes significant especially when the lights are coupled via SMFs from either side of the living body. In this case, for the purpose of investigating influence of the scattering loss in the living body, three kinds of focusers (light condensing modules in which the end part of fiber is set at the position away from focal distance of a lens) with BWs of 10, 0, and 30 μτα are manufactured by way of trial. As a result, the scattering loss is small as the BW becomes smaller. However, it is understood that the BW should be large in terms of coupling loss of fiber and its stability. In the case where the focuser has a BW of 30 μπι, living body loss is 32 dB.

[0073]

Next, the way to grip a living body as the third improvement method will be explained. As a result of experiment on the webbing between the root of the thumb and the index finger, it turns out that sandwiching the living body by a circular disk, which is 3 mm in diameter and made by sapphire, at the right angle to the beam (the sandwiched webbing is oriented to the direction perpendicular to the beam) , reduces the loss in the living body the most.

[0074]

In addition, such a configuration that a heater is mounted on a portion of the forceps-like tool that pinches the living body, so as to change the temperature of the living body may be used, allowing analysis of the aforementioned optical rotation ingredient.

[0075]

Moreover, when the specimen is a part of a living body, a light source near 1310 nm is optimal. The first reason for this is because a 1550 nm wave-long band will be affected by absorption loss of moisture contained in the living body. The second reason is because the core diameter is small when the wavelength is 1060 nm or less, and thus loss of the opposing collimators is approximately 5 dB larger than that of the 1300 nm band^", and absorption loss of the Faraday elements (garnet) which rotate polarized light is large.

[0076]

The conventional optical rotation measuring device cannot separate substances with multiple optical rotations included in a specimen. However, as mentioned above, since the optically rotational ingredient analyzing device, according to the present invention, is capable of measuring temperature characteristics and wavelength characteristics of specific optical rotation for blood sugar level with precision of 0.001 g/dL or less when cell length is 10 mm, analysis of concentration of multiple glucidic ingredients is possible. A method therefor is explained below.

[0077]

Optical rotation angle Θ(Τ, λ) is expressed with the following Equation 1 where Ci denotes concentration of the i-th ingredient, T denotes temperature, Ai(T, λ) denotes optical rotation coefficient or wavelength λ, L denotes specimen length, and N denotes the number of ingredients.

[Equation 1] θ(Τ,λ) =∑CiAi(T, )L/lQ0 (1) where a unit of Ci is g/dL (gram/deciliter) , and a unit of L is dm (decimeter.) Incidentally, optical rotation coefficient A of glucose is approximately 52.7 where T= 20 degrees Celsius and wavelength λ = 589 nm. Therefore, when concentration C, which is a healthy person's blood sugar level, is 0.1, Θ will be approximately 0.005 degrees.

[0078]

Supposing there are three kinds of sugar subjected to analysis, the case where type of sugar is known is explained below. When the substance having optical rotatory is sugar, optical rotation coefficient thereof can be investigated using a science chronological table etc. as long as the type of sugar is known beforehand. However, there may be cases of no experimental data for some wavelengths. In this case, the optically rotational ingredient analyzing device changes the wavelength of the optical rotation coefficient of a pure substance having optical rotatory, which is subjected to measurement, and also changes the temperature for each wavelength at three points: 0, 20, and 40 degrees Celsius, and then measures it. That is, a term Ai(T, λ ) L in Equation 1 can be calculated for i= 1, 2, and 3. Next, temperature of the specimen mixed with three kinds of substances having optical rotatory is changed at three points 0, 20, and 40 degrees Celsius, and then optical rotation Θ at each temperature is measured. Through those operations, three-dimensional, simultaneous linear equations including unknown numbers: CI, C2, and C3 are given, and concentration of each of the three kinds of substances having optical rotatory will be calculated by solving those equations. The wavelength may be changed by N points instead of changing the temperature by N points, for making N-dimensional simultaneous equations. For particularly non-invasive analysis of the optical rotation ingredient, such as blood or a living body, it is easier to change the wavelength of the light source.

[0079]

Here, relationship between the specific optical rotation of a specimen and the light receiving power required for the measurement is considered. It is well-known that the blood sugar level of a healthy person is approximately 0.1 g/dL, and optical rotation angle is approximately 0.005 degrees when the light source is a laser for outputting an orange beam, the specimen is glucose, and cell length L is 10 mm. It will be 0.005 degrees when converted to phase difference. To analyze an optically rotational ingredient based on temperature characteristics of the aforementioned optical rotation, measurement of change in · minute optical rotation due to temperature change is essential. Here, approximately 10% of a healthy person ' s blood sugar level is set as target precision for measurement. In other words, phase difference between the clockwise and the counter-clockwise propagating optical signals in the ring interferometer is 1/100 of 0.005 degrees, or 0.00005 degrees is set as target precision for phase measurement. When the specimen is a 1 mm-thick living body of a healthy person, and the blood sugar level is measured with a ring interferometer, generated phase difference will be 0.0005 degrees, and therefore 0.00005 degrees is equivalent to 10% thereof.

[0080]

S/N ratio of a receiver required to measure phase change Θ of 0.00005 degrees with an optical fiber gyro based on phase modulation is examined hereafter. When a modulation factor is set to the maximum, as illustrated in Non-patent Document 2, the S/N ratio is approximately expressed by the following Equation 2 when light receiving power is comparatively large: [Equation 2]

S / N = sin(0)* Pr* ri / l* e * B (2) where Pr denotes light receiving power, e denotes electronic charge (1.6 x 10^~19) , and B denotes receiving bandwidth (inverse number of integral time) . η denotes quantum efficiency and is assumed 0.5.

[0081]

θ= 0.00005 degrees, Pr = 2 W, and B = 1 Hz (1 second) are substituted into the equation, resulting in an S/N ratio of approximately 1.5. That is, this means that a light receiving power Pr of approximately 2 W is sufficient for measurement of 0.00005 degrees in phase difference in an integral time of 1 second with the S/N ratio of approximately 1.5 dB. When there is ample measuring time and integral time is 4 seconds, Pr = 1 pW may be sufficient.

[0082]

Loss of the optically rotational ingredient analyzing device when the light source wavelength used in the embodiment according to the present invention is 1300 nm band is as follows: Light-source output: approximately 20mW (SLD made by ANRITSU) , and

Optical interferometer loss: approximately 5 dB (optical circulator: 2.0 dB, polarizer: 2.0 dB, others: 1 dB)

Note that since the polarization degree of the light source is high, loss of the polarizer is as low as 2.0 dB. Loss of the specimen (living body) and the polarized-light converting optical system is 35 dB. Total loss in the case of a 1 mm-thick living body is 40 dB. The light receiving level is -27 dBm.

[0083]

Next, the case where the specimen is a liquid, such as glucose or exhaled breath condensate, is explained. In this case, the light-receiving level is improved by approximately 30 dB because there is no living body loss. Therefore, the phase angle may be measured with precision of approximately 0.00005 degrees, and analysis of an optically rotational ingredient is possible by changing the temperature of the specimen and the light source wavelength at N different points, respectively. In addition, a wavelength tunable filter may be used as a method for changing wavelength of the light source to filter an output from the SLD light source 1.

[0084]

Merits in practical use of the measuring device may be raised considerably by measuring beforehand relations: among wavelength variation of the light source, optically rotational ingredient and concentration, among temperature change of the specimen, optically rotational ingredient and concentration, and among wavelength variation of the light source, the temperature change of the specimen, and the optically rotational ingredient and concentration, creating a data table of wavelength/ temperature vs. optically rotational ingredients, analyzing a substance having optical rotatory contained in the specimen as compared to a measured specific optical rotation and concentration of the same, and displaying the measurement results.

[0085]

Fig. 6 is a block diagram of an optical system according to another example of specific optical rotation measuring method used in an embodiment · of the present invention. That is, Fig. 6 illustrates an optical system of the conventional optical system in Fig. 7, in which the specimen 11 is pressed by retainer plates 27-1 and 27-2 from both sides. Distance between PMFs and lens 6-1 and 6-2 is set to be BW = 40/im and WD = 20 mm. In this case, if the focal distance of a lens is 4 mm and the amount of defocusing is 1 mm (fiber is kept 1 mm away from the focal position of the lens) , according to calculations, a beam waist will be 40 μ m and a beam waist position is 20 mm away from the lens. Here, a WD is a working distance which is half of the inter-lens distance. Loss in the living body in this case is 32 dB with a 1 mm-thick living body.

[0086]

As a result of this, in the measurement system of Fig. 6, an approximately 1 mm-thickness part of webbing between the thumb and the index finger is sandwiched and subjected to a glucose load examination, and change in the output of the optical fiber gyro due to change in glucose concentration of a living body is measured successfully.

[0087]

Moreover, according to the specific optical rotation measuring device or the optically rotational ingredient analyzing device described above, an optical signal emitted from the light source is led to the first coupler, the polarizer, and the second coupler, which are all installed on its optical path. The second coupler branches it into two linearly polarized lights, which propagate clockwise and counter-clockwise through the PMFs comprising an optical ring path. They are led to the specimen placed in the optical ring path, from both sides via the polarized-light converting optical systems, which convert to circularly polarized lights orthogonal to each other. The transmitted light beams are led to the PMFs, which constitute the optical ring path, and they are transmitted through the PMFs again in the same mode as that of the linearly polarized lights having entered the specimen. Afterward, they are led to the second coupler, the polarizer, and the first coupler. The first coupler leads them to the photodetector . Finally, the specific optical rotation measuring system measures circular birefringence of the specimen based on phase difference information of the optical signals propagated through the optical ring path clockwise and counter-clockwise; wherein the specimen is a solution; a reagent for breaking a specific substance having optical rotatory down is added to the specimen, and change in the specific optical rotation of the specimen is detected, thereby measuring a specific optical rotation and/or an optically rotational ingredient of the specimen.

[0088]

As mentioned above, while the embodiments according to the present invention are explained referring to drawings, the present invention is not narrowly limited thereto, and many variations are possible based on the technical ideas of the present invention.

Industrial Applicability

[0089]

The optical rotation measuring device and the optically rotational ingredient analyzing device, according to the present invention, are capable of non-invasively measuring specific optical rotation of a substance having optical rotatory with high precision, and invasively or non-invasively measuring temperature characteristics and wavelength characteristics of a specimen with high precision. These measurement results allow analysis of concentration of the ingredients, thereby making relationship among the blood sugar level, blood, a disease etc. clear. As a result, these devices will be used in medical fields etc. widely.

[0090]

Notably, since non-invasive analysis of blood sugar ingredients is possible, there are the following advantages: firstly, a human subject is freed from pain during blood collecting; secondly, it is sanitary because blood collecting is not required from the human subject, and infection to the human subject via a blood collecting instrument etc. is prevented; thirdly, it is economical since no enzymes are used; and fourthly, no waste, such as hypodermic needles and enzymes, is generated. Therefore, those devices according to the present invention are applicable not only in the medical field, but in a wide range of various fields, such as insurance, health and the like.

Description of Reference Numerals

[0091]

1: SLD light source

2-1, 2-2: coupler

3: fiber in-line polarizer - 4-1, 4-2, 4-3: PMF

5: phase modulator

6-1, 6-2, 6-3, 6-4, 6-5, 6-6: lens

7-1, 7-2: polarized-light converting optical system

8-1, 8-2 , 8-3 , 8-4: polarizer

9-1, 9-2, 9-3, 9-4: Faraday element

10-1, 10-2: 1/4 wave plate

11: specimen

12: photodetector

13: signal processing circuit

1 : phase modulation signal

15-1, 15-2: polarization-rotation linearly polarizing module

16-1, 16-2: circularly polarizing module

17-1, 17-2: optical connector

18-1, 18-2: magnet for Faraday elements

19-1, 19-2: circularly polarizing fiber

20-1, 20-2: SMF

21-1, 21-2: TEC section of SMF

21-3, 21-4: TEC section of PMF

22-1, 22-2: fixed base

23: movable linear guide

24: temperature controller

25: optical interferometer

26: forceps -1, 27-2: retainer plate

Claims

1. An optical rotation measuring device comprising:

at least polarization maintaining optical fibers (which are referred to as PMFs hereafter) installed for an optical path for an optical signal, which are used for measurement of specific optical rotation of a specimen mounted on a specimen mounting portion and sandwich the specimen mounting portion, so as to form most of an optical loop path of a ring interferometer (which is referred to as an optical ring path hereafter) for the optical signal; the specimen mounting portion; and polarized-light converting optical systems installed between the PMFs and the specimen mounting portion; wherein

the optical rotation measuring device is configured so as to allow a clockwise and a counter-clockwise propagating optical signal, each propagating through the optical ring path, to propagate through the PMFs in the same form of polarized light, and to propagate through the specimen in the forms of mutually orthogonal polarized lights; and

the polarized-light converting optical systems, which face each other and sandwich the specimen, comprise:

a polarization-rotation linearly polarizing module for rotating by 45 degrees a linearly polarized light propagating through the optical ring path and outputting the resulting linearly polarized light, and a circularly polarizing module for outputting a left-handed or a right-handed circularly polarized light in accordance with a direction of incident linearly-polarized light.

2. The optical rotation measuring device according to claim 1, wherein the circularly polarizing module has a configuration that a condenser lens, a circularly polarized light maintaining fiber, a single mode optical fiber (which is referred to as SMF hereafter) , and a lens are connected in series, and distance between the end part of the SMF and a surface of the lens on the side of facing the end part of the SMF is less than focal length of the lens,

wherein at least one end part of the SMF on the side of facing the specimen is expanded-core or TEC (Thermally diffused Expanded Core) processed, and distance between the end part of the SMF and a surface of the lens on the side of facing the end part of the SMF is less than focal length of the lens.

3. The optical rotation measuring device according to claim 1, wherein: the circularly polarizing module has a configuration that a condenser lens, a circularly polarized light maintaining fiber, an SMF, and a lens are connected in series, at least the end part of the SMF on the side of facing the specimen is expanded-core or TEC processed, and a lens on the side of the specimen is not used.

4. An optical rotation measuring device comprising:

the polarized-light converting optical systems use a polarization plane rotary element, which rotates the polarization plane of an optical signal by 45 degrees either clockwise or counter-clockwise in the traveling direction of the optical signal when a polarized light beam enters one side of the polarization plane rotary element as the optical signal, and rotates in the reverse direction the polarization plane of an optical signal by 45 degrees in the traveling direction of the optical signal when a polarized light beam enters the other side of the polarization plane rotary element as the optical signal, which is opposite to the case where a polarized light beam enters the one side of the polarization plane rotary element; and

at least one end face of the PMFs on the side of facing the polarized-light converting optical systems is TEC processed.

5. The optical rotation measuring device according to claim 1, wherein the polarization plane rotary element of the polarized-light converting optical systems uses a polarization plane rotary element, which rotates the polarization plane of an optical signal by 45 degrees either clockwise or counter-clockwise in the traveling direction of the optical signal when a linearly polarized light beam enters one side of the polarization plane rotary element as the optical signal, and rotates in the reverse direction the polarization plane of an optical signal by 45 degrees in the traveling direction of the optical signal when a linearly polarized light beam enters the other side of the polarization plane rotary element as the optical signal, which is opposite to the case where a linearly polarized light beam enters the one side of the polarization plane rotary element.

6. The optical rotation measuring device according to claim 1, wherein the optical rotation measuring device further comprises an optical rotation measuring system in which:

an optical signal emitted from a light source is led to a first coupler, an in-line polarizer, and a second coupler, which are installed on an optical path;

the second coupler branches the optical signal into two linearly polarized lights, which propagate in both directions through the PMFs that comprise an optical ring path and sandwich the specimen;

the optical signals propagated through the optical ring path are led to the specimen, which is placed on the optical ring path, from either side of the specimen via the polarized-light converting optical systems, which convert the optical signal to circularly polarized lights orthogonal to each other;

the resulting transmitted lights are converted to be in the same mode as that of the linearly polarized lights output to the specimen, coupled to the PMFs which constitute the optical ring path, led to the second coupler and the in-line polarizer again, and led to a photodetector by the first coupler; and

circular birefringence of the specimen is measured based on phase difference information of the optical signals propagated through the optical ring path clockwise and counter-clockwise; wherein the optical rotation measuring device further comprises a device for changing either or both temperature of the specimen and wavelength of the light source.

7. The optical rotation measuring device according to claim 1, wherein either one of the polarized-light converting optical systems, which face each other and sandwich the specimen, is installed on a movable linear guide, and the opposing polarized-light converting optical systems are opposing collimator optical systems, which keep optical coupling between the PMFs even if the distance between both of the opposing polarized-light converting optical systems changes.

8. The optical rotation measuring device according to claim 1, wherein either one of the polarized-light converting optical systems, which face each other and sandwich the specimen, is installed on a fixed base, and the other one is installed on a movable base, and each of the polarized-light converting optical system on the fixed base and the polarized-light converting optical system on the movable base is installed facing a part of the forceps-like tool that pinches the specimen .

9. The optical rotation measuring device according to claim 1, wherein wavelength of the light source is of a 1300 nm band when the specimen is a light-scattering specimen such as blood serum or a living body.

10. An optically rotational ingredient analyzing device comprising: at least polarization maintaining optical fibers (which are referred to as PMFs hereafter) installed for an optical path for an optical signal, which are used for measurement of specific optical rotation of a specimen mounted on a specimen mounting portion and sandwich the specimen mounting portion, so as to form most of an optical loop path of a ring interferometer (which is referred to as an optical ^■ ring path hereafter) for the optical signal; the specimen mounting portion; and polarized-light converting optical systems installed between the PMFs and the specimen mounting portion; wherein

the optically rotational ingredient analyzing device is configured so as to allow a clockwise and a counter-clockwise propagating optical signal, each propagating through the optical ring path, to propagate through the PMFs in the same form of polarized light, and to propagate through the specimen in the forms of mutually orthogonal polarized lights ;

an polarization-rotation linearly polarizing module for rotating by 45 degrees a linearly polarized light propagating through the optical ring path and outputting the resulting linearly polarized light, and a circularly polarizing module for outputting a left-handed or a right-handed circularly polarized light in accordance with a FAST axial mode or a SLOW axial mode of output polarization modes; and

the optically rotational ingredient analyzing device further comprises at least either a wavelength changing device for changing wavelength of the optical signal, which is led to the specimen, or a temperature changing device for changing temperature of the specimen, and obtains information of optically rotational ingredients contained in the specimen based on the measurement results of change in phase difference information of the specimen, which is dependent on at least either wavelength change of the optical signal or temperature change of the specimen.

11. The optically rotational ingredient analyzing device according to claim 10, wherein the circularly polarizing module has a configuration that a circularly polarized light maintaining fiber, a single mode optical fiber (which is referred to as SMF hereafter) , and a lens are connected in series, and distance between the end part of the SMF and a surface of the lens on the side of facing the end part of the SMF is less than focal length of the lens; and at least one end part of the SMF on the side of facing the specimen ^■is expanded-core or- TEC (Thermally diffused Expanded Core) processed, and distance between the end part of the SMF and a surface of the lens on the side of facing the end part of the SMF is less than focal length of the lens.

12. The optically rotational ingredient analyzing device according to claim 10, wherein

the circularly polarizing module has a configuration that a condenser lens, a circularly polarized light maintaining fiber, an SMF, and a lens are connected in series, wherein at least the end part of the SMF on the side of facing the specimen is expanded-core (TEC) processed, and a lens on the side of the specimen is not used.

13. The optically rotational ingredient analyzing device according to claim 10, wherein the optically rotational ingredient analyzing device further comprises an optical rotation measuring system in which:

the second coupler branches the optical signal into two linearly polarized lights, which propagate in both directions through the PMFs that comprise an optical ring path and sandwich the specimen, and the branched optical signal propagates through the optical ring path;

the optical signals propagated through the optical ring path are led to the specimen, which is placed on the optical ring path, from either side of the specimen via the polarized-light converting optical systems, which convert the optical signal to circularly polarized lights orthogonal to each other; the resulting transmitted lights are converted to be in the same mode as that of the linearly polarized lights output to the specimen, coupled to the PMFs which constitute the optical ring path, led to the second coupler and the in-line polarizer again, and led to a photodetector by the first coupler; and

circular birefringence of the specimen is measured based on phase difference- information of the optical signals propagated through the optical ring path clockwise and counter-clockwise.

14. The optically rotational ingredient analyzing device according to claim 10, wherein

either one of the polarized-light converting optical systems, which face each other and sandwich the specimen, is installed on a movable linear guide, and the opposing polarized-light converting optical systems are opposing collimator optical systems, which keep optical coupling between the PMFs even if the distance between both of the opposing polarized-light converting optical systems changes.

15. The optically rotational ingredient analyzing device according to claim 10, wherein

either one of the polarized-light converting optical systems, which face each other and sandwich the specimen, is installed on a fixed base, and the other one is installed on a movable base, and each of the polarized-light converting optical system on the fixed base and the polarized-light converting optical system on the movable base is installed facing a part of the forceps-like tool that pinches the specimen .

16. The optically rotational ingredient analyzing device according to claim 10, wherein

the optical rotation of the specimen is measured while changing the temperature of the specimen or changing the wavelength of the light source, or changing both the temperature and the wavelength at N points, and solving N-dimensional simultaneous linear equations and finding ingredient concentration of N kinds of substances having optical rotatory contained in the specimen is calculated where N denotes an integer .

17. The optically rotational ingredient analyzing device according to claim 10, wherein

the optically rotational ingredient analyzing device determines ingredient concentration of N kinds of substances having optical rotatory contained in the specimen using a corresponding table, which allows identification of a corresponding relationship between information of change in temperature of the specimen, change in wavelength of the light source, or information of both of these changes, and at least one of change in the optical rotation of the specimen, the optically rotational ingredient, and concentration of the optically rotational ingredient.

18. The optically rotational ingredient analyzing device according to claim 10, wherein wavelength of the light source is of a 1300 nm band when the specimen is a light-scattering specimen such as blood serum or a living body.

19. An optically rotational ingredient analyzing method using an optical fiber ring interferometer, comprising the steps of: preparing an optical ring path, which comprises an optical path constituted mainly by polarization maintaining optical fibers (which are referred to as PMFs hereafter) sandwiching a specimen and polarized-light converting optical systems that are inserted facing each other and sandwiching a specimen;

preparing either a means for changing temperature of the specimen or a means for changing wavelength of a light source, or both of these means;

transmitting an optical signal in both directions in the same mode through the PMFs along the optical path, and making circularly polarized lights orthogonal to each other enter the specimen in the either of the directions towards the specimen by polarized-light converting optical systems;

preparing a polarization-rotation linearly polarizing module and a circularly polarizing module as the polarized-light converting optical systems; and

preparing a polarization plane rotary element for the polarization-rotation linearly polarizing module, which rotates the polarization plane of an optical signal by 45 degrees either clockwise or counter-clockwise in the traveling direction of the optical signal when a polarized light beam enters one side of the polarization plane rotary element as the optical signal, and rotates in the reverse direction the polarization plane of an optical signal by 45 degrees in the traveling direction of the optical signal when a polarized light beam enters the other side of the polarization plane rotary element as the optical signal, which is opposite to case where a polarized light beam enters the one side of the polarization plane rotary element; wherein

the interferometer comprises the step of obtaining information of optically rotational ingredients contained in the specimen based on the measurement results of change in phase difference information of the specimen, which is dependent on at least either wavelength change of the optical signal or temperature change of the specimen.

20. An optically rotational ingredient analyzing method, comprising the steps of:

preparing an optically rotational ingredient analyzing system having at least polarization maintaining optical fibers (which are referred to as PMFs hereafter) installed for an optical path for an optical signal, which are used for measurement of optically rotational ingredient of a specimen mounted on a specimen mounting portion and sandwich the specimen mounting portion, so as to form an optical loop path of a ring interferometer (which is referred to as an optical ring path hereafter) for the optical signal; the specimen mounting portion; and polarized-light converting optical systems installed between the PMFs and the specimen mounting portion; and polarized-light converting optical systems installed between the PMFs and the specimen mounting portion;

configuring the optically rotational ingredient analyzing system so as for the optical signal each propagating through the optical ring path clockwise and counter-clockwise, to propagate through the PMFs in the same form of polarized light, and to propagate through the specimen in the forms of mutually orthogonal polarized lights;

preparing a polarization plane rotary element in the polarized-light converting optical systems, which rotates the polarization plane of an optical signal by 45 degrees either clockwise or counter-clockwise in the traveling direction of the optical signal when a polarized light beam enters one side of the polarization plane rotary element as the optical signal, and rotates in the reverse direction the polarization plane of an optical signal by 45 degrees in the traveling direction of the optical signal when a polarized light beam enters the other side of the polarization plane rotary element as the optical signal, which is opposite to the case where a polarized light beam enters the one side of the polarization plane rotary element ;

preparing PMFs where at least one end face of the PMFs is TEC (Thermally diffused Expanded Core) processed on the side of facing the polarized-light converting optical systems, preparing at least either a wavelength changing device for changing wavelength of the optical signal, which is led to the specimen, or a temperature changing device for changing temperature of the specimen; and

obtaining information of optically rotational ingredients contained in the specimen based on the measurement results of change in phase difference information of the specimen, which is dependent on at least either wavelength change of the optical signal or temperature change of the specimen.