WO2002006862A1

WO2002006862A1 - Optical device having wavelength selectivity and its manufacturing method

Info

Publication number: WO2002006862A1
Application number: PCT/JP2001/006012
Authority: WO
Inventors: Toshiaki Anzaki; Takayuki Toyoshima
Original assignee: Nippon Sheet Glass Co., Ltd.
Priority date: 2000-07-13
Filing date: 2001-07-11
Publication date: 2002-01-24
Also published as: JP2002022939A

Abstract

An optical device produced at lowered cost and having a wavelength selectivity and its manufacturing method are disclosed. The optical device has a base (12) having a curved surface and an optical film (13) formed on the base and having a thickness varying from one position to another on the curved surface. The optical film (13) is formed on the base from a predetermined direction.

Description

Optical element having wavelength selectivity and method for manufacturing the same

C technical field]

The present invention relates to an optical element used for optical communication such as wavelength division multiplexing communication, and is particularly suitable for multiplexing (multiplexing) of light having different wavelengths or demultiplexing of multiplexed light for each wavelength. The present invention relates to an optical element having wavelength selectivity and a method for manufacturing the same.

[Background technology]

Conventionally, optical elements such as an optical fiber / collimator lens have been used for optical communication equipment. As optical communication becomes more widespread in the future, it will become increasingly necessary to downsize and integrate optical communication equipment. In addition, optical communication requires a technology for splitting light by selectively transmitting or reflecting light for each wavelength. Therefore, for example, an optical filter such as an edge filter or a narrow-band filter, which is a multilayer filter in which high-refractive-index dielectric layers and low-refractive-index dielectric layers are alternately stacked, has been proposed.

FIG. 9 is a schematic diagram of a conventional optical communication device 100 using an optical filter. The optical communication device 100 demultiplexes a mixed optical signal of optical signals (Chl to 8) having eight different wavelengths and outputs a plurality of optical signals. The optical communication device 100 includes collimator lenses 101, 102, 104 to 119, each of which is a rod lens, an attenuator 103, and optical filters F1 to F9. The attenuator 103 attenuates the light intensity of the incident light to a predetermined value. An optical signal is sent between the lens, the attenuator 103, and the filter via the optical fiber.

First, the mixed optical signal incident on the optical communication device 100 is separated into a transmitted optical signal (optical signal Ch5) and a reflected optical signal (optical signals Ch1 to 4, 6 to 8) by the optical filter F5. The optical intensity of the optical signal Ch5, which is a transmitted optical signal, is attenuated to a predetermined value by the attenuator 103, and the attenuated optical signal Ch5 is emitted from the attenuator 103. The optical signals Ch 1 to 4 and 6 to 8 which are the reflected light signals of the optical filter F 5 are transmitted by the optical filter F 9 to the transmitted light signal (optical signal Ch 6 to 8) and the reflected light signal (optical signal Ch 1 to 4). And divided into Optical signal C that is the transmitted optical signal h 6 to 8 are separated into a transmitted light signal (optical signal Ch 6) and a reflected light signal (optical signals Ch 7 and 8) by the optical filter F 6, and the transmitted optical signal Ch 6 is a collimator The light exits through the lens 107. On the other hand, the optical signals Ch7 and 8, which are the reflected light signals of the optical filter F6, are separated into a transmitted light signal (optical signal Ch7) and a reflected light signal (optical signal Ch8) by the optical filter F7. . The optical signal Ch 7 is emitted through the collimator lens 109, and the optical signal Ch 8 is transmitted through the optical filter F 8 and emitted through the collimator lens 111. The optical signal Ch :! to 4 which is the reflected light signal of the optical filter F 9 is divided into the transmitted light signal (optical signal Ch i) and the reflected light signal (optical signal Ch 2 to 4) by the optical filter F 1. The optical signal Ch1 is emitted through the collimator lens 113. On the other hand, the optical signals Ch2 to Ch4, which are the reflected optical signals of the optical filter F1, are separated by the optical filter F2 into a transmitted optical signal (optical signal Ch2) and a reflected optical signal (optical signals Ch3, 4). The optical signal Ch 2 is emitted through the collimator lens 115. On the other hand, the optical signals Ch3 and Ch4, which are reflected optical signals of the optical filter F2, are separated into a transmitted optical signal (optical signal Ch3) and a reflected optical signal (optical signal Ch4) by the optical filter F3. . The optical signal Ch3, which is the transmitted light signal, is emitted through the collimator lens 117, and the optical signal Ch4, which is the reflected light signal of the optical filter F3, passes through the optical filter F4 and passes through the collimator lens 119. And is emitted. .

By the way, the optical communication device 100 of FIG. 9 has the following problems.

(1) A large number of optical filters are required to divide the mixed optical signal into light having different wavelengths, and it takes time to form these optical filters, and the manufacturing cost of optical communication equipment 100 increases. I do.

(2) If multiple optical filters are used, it is necessary to attenuate or amplify the optical signal to make the optical signal intensities approximately equal, and the use of the attenuator or amplifier increases the cost. I do.

(3) It is necessary to individually assemble a large number of optical filters on the end faces of a plurality of corresponding collimator lenses. In addition, since the collimator lenses are small, the work of assembling the optical filters is very detailed. For this reason, it is difficult to manufacture the optical communication device 100, and the working efficiency is reduced and the manufacturing cost is increased. (4) Alignment work is required to match the optical axes of the collimator lenses before and after each optical filter, and it is necessary to perform these alignment work by the number of optical filters. Therefore, the manufacturing cost of the optical communication device 100 increases.

[Disclosure of the Invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical element having a wavelength selectivity which can be easily manufactured and whose manufacturing cost is reduced, and a method for manufacturing the same.

According to a first aspect of the present invention, there is provided an optical element having wavelength selectivity. The optical element includes a substrate having a curved surface or a plurality of planes, and an optical film formed on a surface of the substrate and having a film thickness varying between different positions on the curved surface or the plurality of planes.

According to a second aspect of the present invention, there is provided a method for manufacturing an optical element having wavelength selectivity. The manufacturing method includes a step of preparing a substrate having a curved surface or a plurality of planes, and changing between different positions on the curved surface or the plurality of planes by forming a film on a surface of the substrate from a predetermined direction. Forming an optical film having a thickness.

According to a third aspect of the present invention, there is provided an optical element disposed at one end of an optical fiber. The optical element has a curved surface or a plurality of planes, and has a light-transmitting substrate, and a film thickness formed on a surface of the substrate and varying between different positions on the curved surface or the plurality of planes. An optical film.

In a fourth aspect of the present invention, a wavelength selection device is provided. The wavelength selecting device includes: an optical fiber; a parallel light emitting element that converts light emitted from the optical fiber into parallel light; and an optical element that receives parallel light emitted from the light emitting element and has wavelength selectivity. And. The optical element includes a substrate having a curved surface or a plurality of planes, and an optical film formed on the surface of the substrate and having a different thickness depending on the position on the curved surface or the plurality of planes. The wavelength of the light to be selected can be changed by rotating or moving the optical element to change the incident position of the parallel light on the optical film. [Brief description of drawings] For a better understanding of the invention, together with objects and features of the invention, reference is made to the following description of exemplary embodiments, taken in conjunction with the accompanying drawings.

FIG. 1 is a schematic front view of an optical element according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an optical element according to a second embodiment of the present invention.

FIG. 3 is a schematic front view of an optical element according to a third embodiment of the present invention.

FIG. 4 is a schematic front view of an optical element according to a fourth embodiment of the present invention.

FIG. 5 is an explanatory view showing how to use the optical element of FIG.

FIG. 6 is a schematic side view of an optical element according to a fifth embodiment of the present invention.

FIG. 5 is a schematic configuration of an optical element according to a sixth embodiment of the present invention.

FIG. 8 is a perspective view of a three-dimensional structure of a modification of the optical element in FIG.

FIG. 9 is a schematic plan view of a conventional optical communication device.

[Best Mode for Carrying Out the Invention]

[First Embodiment]

An optical element 11 according to a first embodiment of the present invention and a method for manufacturing the same will be described with reference to FIG. The optical element 11 is made of a translucent material, preferably transparent glass, and has a spherical base 12, and a multilayer filter 1 as an optical film formed on the surface of the base 12. Including 3. The multilayer filter 13 is formed, for example, by alternately stacking high-refractive-index dielectric layers and low-refractive-index dielectric layers.

The multilayer filter 13 has a different thickness depending on the position on the surface of the substrate 12. Specifically, the multilayer film filter 13 is applied to the surface of the substrate 12 from a predetermined direction indicated by an arrow A in FIG. It is formed using a method. Due to such film formation, the film thickness of the multilayer film finoletor 13 formed on the surface of the substrate 12 is different at each part of the surface of the substrate 12 according to the normal angle に対する to the film formation direction A. That is, the film thickness at the reference position B on the surface of the substrate 12 where the film forming direction A and the normal direction coincide with each other (the film thickness at the time of vertical film formation) is the largest, and the normal line from the reference position B As the angle Θ increases, the film thickness gradually decreases. Substrate 1 2 Multilayer filter at surface position at normal angle Θ on surface The film thickness d of 13 is expressed by the following equation.

d = D c o s Θ

Here, D is the film thickness during vertical film formation (that is, the film thickness at the reference position B).

In this way, the film thickness of the multilayer filter 13 is determined by multiplying the film thickness D at the reference position B by c os 応じ according to the normal angle に対する with respect to the film forming direction (the flying direction of the film-formed particles) A. The selected wavelength that can be extracted at the surface position at the normal angle Θ on the surface of the substrate 12 is expressed by the following equation.

λ = 0 c 0 s Θ

Here, λ 0 is a design wavelength at the time of vertical film formation.

Thus, the selected wavelength extracted from the multilayer filter 13 can be determined based on the position of the incident light with respect to the multilayer filter 13. In order to change the position of the incident light of the filter 13 (to change the selected wavelength), for example, a multilayer filter 13 is formed around an axis passing through the center (spherical center) の of the substrate 12. What is necessary is just to rotate the base 12 within the set area.

The multilayer filter 13 may be formed by a vacuum deposition method, a magnetron sputtering method, an ion beam sputtering method, an ion assist deposition method, or the like, in addition to the sputtering method.

The optical element 11 of the first embodiment has the following advantages.

(A) The multilayer filter 13 has a substrate 1 such that its film thickness d varies according to a normal angle 0 to the film forming direction Α (the film thickness varies according to the position on the surface of the substrate 12). 2 is formed on the surface. Therefore, by rotating the base 12 about the axis, the surface position of the multilayer filter 13 on which light enters is changed, and as a result, the selected wavelength (λ) extracted from the multilayer filter 13 is changed. 1 to λ η) can be easily changed.

(Mouth) Since the selected wavelength is changed only by the multilayer filter 13, it is not necessary to use a large number of optical filters as in the prior art. Therefore, the optical element 11 that can be easily manufactured and has a reduced manufacturing cost can be obtained.

(C) Since the substrate 12 is made of transparent glass, the substrate 12 is rotated to rotate the multilayer film. The wavelength of the light passing through the multilayer filter 13 can be easily changed only by changing the incident position of the light on the filter 13.

(2) Since the substrate 12 is a sphere, a multilayer filter 13 whose film thickness is continuously reduced as the normal angle Θ from the reference position B increases is obtained. Therefore, the selected wavelength extracted from the multilayer filter 13 can be continuously changed by changing the light incident position on the multilayer filter 13.

(E) A multilayer filter 13 is formed on the surface of the substrate 12 from a predetermined direction (film formation direction A). Therefore, the film thickness of the multilayer filter 13 varies depending on the normal angle 0 of each part of the surface of the substrate 12. Therefore, the multilayer filter 13 having a variable thickness can be easily formed on the surface of the substrate 12 without performing a difficult film thickness correction technique using a tool such as a correction plate.

[Second embodiment]

Next, an optical element 20 according to a second embodiment of the present invention will be described with reference to FIG. The optical element 20 includes an optical fiber 21, a base 12 A formed at an end of the optical fiber 21, and a multilayer filter 13 A formed on the surface of the base 12 A. Prepare. The substrate 12A is made of a light-transmitting material, preferably transparent glass, and has a cap-like sphere shape. The multilayer filter 13A is formed in the same manner as the multilayer filter 13 of the first embodiment.

The optical element 20 of the second embodiment has the following advantages.

(F) The film thickness of the multilayer H13 filter 13A differs depending on the position on the surface of the substrate 12A. Therefore, by selecting the transmitted light signal in any direction that passes through the optical fiber 121, the base 12A, and the multilayer filter 13A, the selected wavelength of the light extracted from the multilayer filter 13A can be reduced. Changes are easy. For example, by receiving the transmitted light signal T1 through the optical fiber 22, a transmitted light signal having the wavelength 1 can be selected. By receiving the transmitted light signal T i through the optical fiber 23, a transmitted light signal having a wavelength λ i can be selected. Further, by receiving the transmitted light signal Tn through the optical fiber 24, it is possible to select a transmitted light signal having a wavelength; Lη.

[Third embodiment]

Next, an optical element 30 according to a third embodiment of the present invention will be described with reference to FIG. Optical element The child 30 includes a base 31 having a spheroidal shape, and a multilayer film finoletor 13B formed on the surface of the base 31. The base 31 is made of a translucent material, preferably transparent glass. The surface of the base 31 is formed by rotating the ellipsoid about the major axis of the ellipse. The multilayer filter 13A is formed on a surface (spheroid) of the substrate 31 having a relatively small change in radius of curvature from a predetermined direction by a physical vapor phase method such as a sputtering method.

According to the third embodiment, the following advantages are provided.

The multilayer filter 13A is formed on the surface of the base 31 having a spheroidal shape, where the rate of change of the radius of curvature is relatively small. Accordingly, as compared with the first embodiment, the wavelength change ratio Δλ with respect to the change in the surface position of the multilayer filter 13A is reduced, and the selected wavelength extracted from the multilayer filter 13A is reduced. The selection can be made more finely.

[Fourth embodiment]

An optical element 40 according to a fourth embodiment of the present invention will be described with reference to FIGS. The optical element 40 includes a base 41 having an octahedral shape and a multilayer filter 13 C formed on an outer peripheral surface (surface) having a plurality of contact surfaces (planes) adjacent to each other at a predetermined angle. Prepare. That is, the multilayer filter 13 C is formed on the plane of the base 41. The base 41 is made of a light-transmitting material, preferably transparent glass. The multilayer filter 13 C is formed in the same manner as the multilayer filter 13 in FIG. Of the outer peripheral surface of the base 41, which is an octahedron, the film thickness of the multilayer filter 13C of the first contact surface and the multilayer film finoleta 13C of the second contact surface adjacent to the first contact surface The film thickness is different. That is, as shown in FIG. 5, the film thickness of the multilayer filter 13 C formed on the contact surface (first side surface) 42 whose normal / normal angle is Θi is represented by θ The multilayer filter 13C formed on the contact surface 43 (adjacent second side surface) where η (θ η> θ i) is larger than B in thickness.

The optical element 40 of the fourth embodiment has the following advantages.

Since the thickness of the multilayer filter 13 C at each contact surface (adjacent side surface) on the outer peripheral surface of the polygonal base 41 is different, the optical element 40 is rotated to make the multilayer filter 13 C and light is incident. By changing the surface position, the selected wavelength extracted from the filter 13C can be discontinuously changed. Can be changed to

[Fifth Embodiment]

An optical element 50 according to a fifth embodiment of the present invention will be described with reference to FIG. The optical element 50 has a substrate 52 and a base 51 formed on the substrate 52. The base 51 includes a plurality of prism-shaped inclined protrusions 53-57 each having inclined surfaces having different angles. The substrate 51 is made of a light-transmitting material, preferably transparent glass. A multilayer filter 13D having a film thickness corresponding to each inclination angle is formed on each slope of each of the inclined protrusions 53 to 57. That is, the film thickness of the multilayer filter 13D is different for each inclined surface of the inclined protrusions 53 to 57. That is, the film thickness of the multilayer filter 13D becomes smaller as the inclined surface becomes larger. The optical element 50 of the fifth embodiment has the following advantages.

The film thickness of the multilayer filter 13D differs between adjacent inclined surfaces of the inclined protrusions 53 to 57. Therefore, by sliding the substrate 51 in the direction indicated by the arrow C in FIG. 6 to change one or more inclined surfaces on which the mixed optical signal including a plurality of wavelengths is to be incident, the multilayer filter 1 is formed. The selected wavelength extracted from 3D can be changed discontinuously. For example, as shown in FIG. 6, when a mixed optical signal is incident from below the substrate 52 toward the base 51, one or a plurality of inclined projections to which the mixed optical signal is to be incident are selected. Then, by receiving light that is transmitted in a direction perpendicular to the inclined surface of the selected inclined protrusion, light having a wavelength corresponding to the film thickness of the inclined surface through which the mixed optical signal has passed can be extracted. . Conversely, when a mixed optical signal is incident on the base 51 from above the inclined projections 53 to 57, one or a plurality of inclined projections to which the mixed optical signal is to be incident are selected. You. Then, by receiving light that is transmitted in a direction perpendicular to the inclined surface of the selected inclined protrusion, light having a wavelength corresponding to the film thickness of the inclined surface through which the mixed optical signal has passed can be extracted. .

[Sixth embodiment]

Next, a sixth embodiment of the present invention using one of the optical elements 11 (FIG. 1), 30 (FIG. 3), 40 (FIG. 4) and 50 (FIG. 6). The wavelength selection device 60 will be described with reference to FIG. The wavelength selection device 60 includes a main body 63, and converts the light transmitted through the optical element 61 and the optical fiber 61 into parallel light in the main body 63, and converts the parallel light to the optical element 11 1. A collimator lens (parallel light emitting portion) 62 for emitting light is provided. The optical fiber 61 is supported by the main body 63 via a capillary 64. The wavelength to be selected is changed by rotating the optical element 11 to change the incident position of the parallel light on the multilayer filter 13. The wavelength selection device 60 of the sixth embodiment has the following advantages.

The optical element 11 is arranged in the main body 63, and by rotating the optical element 111 by a movable mechanism or the like, the incident position of the parallel light on the multilayer filter 13 changes, and the optical element 11 is extracted from the optical element 11. The selected wavelength of the light to be emitted is changed. Therefore, a tunable device for extracting the selected wavelength is obtained.

An optical element 30 or 40 may be provided in the main body 63 instead of the optical element 11. In this case, by rotating the optical element 30 or 40, the selected wavelength of light extracted from the optical element is changed.

When the optical element 50 of FIG. 6 is provided in the main body 63, the selected wavelength extracted from the optical element 50 can be changed by horizontally moving the optical element 50.

It will be apparent to one skilled in the art that the present invention may be embodied in other alternatives without departing from the spirit and scope of the invention. In particular, the present invention may be modified as follows. Instead of forming the multilayer filter 13 on the surface of the base 12 having a spherical shape, a multilayer filter is formed on the outer peripheral surface 71 of a cylindrical body 70 made of, for example, transparent glass as shown in FIG. You can.

In the second embodiment, a base 12A made of a hemisphere may be provided at the end of the optical fiber 121. ,

In the fourth embodiment, a base 41 made of a polyhedron other than the octahedron may be formed. In the sixth embodiment, the optical fiber 61, the capillary 64, and the collimator lens 62 may be formed from one element.

In addition, the cavities 64 and the collimator lenses 62 may be arrayed.

Claims

The scope of the claims

1. An optical element (11, 20, 30, 40, 50, 60) having wavelength selectivity,

A curved surface or a layer having a plurality of planes, a substrate (12, 12A, 31, 41, 51), and a film thickness formed on the surface of the substrate and varying according to the position on the curved surface or the plurality of planes An optical element comprising: an optical film (13, 13A, 13B, 13C, 13D) having:

2. The optical element according to claim 1, wherein the optical film has a thickness such that the optical film becomes thinner as a normal angle to a predetermined reference position on the surface of the substrate increases.

3. The optical element according to claim 1, wherein the base has a light transmitting property.

4. The optical element according to any one of claims 1 to 3, wherein the base is a sphere or an ellipsoid.

5. Claim :! In the optical element according to any one of (1) to (3), the base is a polyhedron.

6. The optical element according to any one of claims 1 to 3, wherein the base is a substrate (52);

A plurality of inclined protrusions (53 to 57) each having an inclined surface having a different angle disposed on the substrate.

7. A method for producing an optical element (11, 20, 30, 40, 50, 60) having wavelength selectivity, comprising: 'a substrate having a curved surface or a plurality of flat surfaces (12, 12A, 31, 41, 51, 51); Prepare Process,

An optical film (13, 13A, 13B, 13C, 13D) having a film thickness that changes between different positions on the curved surface or a plurality of planes by forming a film on the surface of the substrate from a predetermined direction. A) forming an optical element.

8. In the method of manufacturing an optical element according to claim 7, the step of forming the optical film is performed such that the film thickness decreases as the normal angle to a predetermined reference position on the surface of the substrate increases. Forming a film.

9. According to the method for manufacturing an optical element according to claim 7 or 8, the base has a light-transmitting property.

10. In the method of manufacturing an optical element according to any one of claims 7 to 9, wherein the base is a sphere or an ellipsoid.

11. The method for manufacturing an optical element according to claim 7, wherein the substrate is a polyhedron.

12. The method for producing an optical element according to any one of claims 7 to 9, wherein the base is:

Substrate (52),

A plurality of inclined projections (53 to 53) each having an inclined surface having a different angle disposed on the substrate;

57)

13. The optical element (11, 20, 30, 40, 50,

60)

A substrate that has a curved surface or a plurality of flat surfaces and is light-transmissive (12, 12A, 31, 4 1, 51)

An optical film (13, 13A, 13B, 13C, 13D) formed on the surface of the substrate and having a film thickness changing between different positions on the curved surface or the plurality of planes. .

14. A wavelength selection device (60),

Optical fiber (61),

A light emitting element (62) for converting light emitted from the optical fiber into parallel light, and an optical element (11, 30, 40, 40) for receiving parallel light emitted from the parallel light emitting element and having wavelength selectivity. 50) and the optical element is

A substrate (12, 31, 41, 51) having a curved surface or a plurality of planes adjacent at a predetermined angle;

An optical film (13, 13B, 13C, 13D) formed on a surface of the substrate, wherein the curved surface or the layer has a film thickness that changes between different positions on a plurality of planes; A wavelength selection device that can change the wavelength of the light to be selected by rotating or moving to change the incident position of the parallel light on the optical film.

15. In the wavelength selection device according to claim 14, the optical film has a film thickness that becomes thinner as the normal angle to a predetermined reference position on the surface of the substrate increases.

16. A wavelength selective device according to claim 14 or 15! / The base has translucency.

17. The wavelength selection device according to any one of claims 14 to 16, wherein the base is a sphere or an ellipsoid.

18. Claim 14-: In the wavelength selection device according to any one of L6, The substrate is a polyhedron.

19. The wavelength selection device according to any one of claims 14 to 16, wherein the substrate comprises:

Substrate (52),

And a plurality of inclined projections (53 to 57) arranged on the substrate, each having an inclined surface having a different angle.