JP5672923B2 - Optical module - Google Patents

Description

The present invention transmits an optical signal using an optical fiber, received relates to an optical module for transmitting and receiving.

  An optical module for transmission used in optical communication uses light from a laser diode (LD) as signal light, and the signal light is collected by a lens and coupled to a communication optical fiber. . The receiving optical module collects the signal light transmitted through the optical fiber with a lens and receives it with a receiving photodiode (PD). There is also a single-fiber bidirectional transmission / reception optical module that performs both transmission and reception using a single optical fiber.

  In the optical module for optical communication described above, when a plurality of signal lights having different wavelengths are multiplexed and transmitted / received using a plurality of transmission LDs and reception PDs, an optical path between an optical element such as an LD or PD and an optical fiber In the system, an optical isolator, a prism, a wavelength demultiplexing filter (hereinafter referred to as a WDM filter), or the like is arranged. In such an optical module, the optical path length becomes long, and it is difficult to adjust and set the focal position and the working distance using one lens.

  For this reason, two optical lenses are used, and a collimating lens is used for one of them and optically coupled with a parallel beam so that a predetermined optical path length can be secured. In addition, two condensing lenses are used, and the imaging positions (condensing positions) of both lenses are matched and optically coupled to obtain a predetermined optical path length (see, for example, Patent Document 1).

JP 9-2111258 A

  FIG. 13 shows two optical signals for transmission / reception that transmit two types of signal light having different wavelengths using two LDs and receive signal light of a predetermined wavelength using one PD. This is an example in which the optical path system is configured as a parallel beam. In this optical module 100, a sleeve 106 that accommodates and holds an optical fiber 102 is fixed to one end of a housing 101, and a first transmission unit 107 that has a first LD 103 mounted is fixed to an opposite end. The second transmission unit 108 in which the second LD 104 is mounted is fixed to the side surface of the housing 101, and the reception unit 109 in which the PD 105 is mounted is fixed to the opposite side surface of the housing 101.

  A first lens (for example, a collimating lens) 111 having a condensing position is fixedly arranged in the housing 101 at the fiber end 102 a of the optical fiber 102, and is condensed on the LD 103 in the first transmission unit 107. A second lens 112a having a position is disposed, and the first lens 111 and the second lens 112a are optically coupled by a parallel beam. Then, the signal light (wavelength λ1) from the LD 103 passes through the second WDM filter 114, the optical isolator 115, and the first WDM filter 113 disposed between the lens 111 and the lens 112a, and enters the fiber end 102a. Incident.

  Further, the LD 104 in the second transmission unit 108 is optically coupled with a second lens (condensing lens) 112b disposed in the second transmission unit 108 by a parallel beam. The signal light (wavelength λ2) from the LD 104 is reflected by the second WDM filter 114, passes through the optical isolator 115 and the first WDM filter 113, and enters the fiber end 102a. Further, the PD 105 in the receiving unit 109 is optically coupled with a second lens (condensing lens) 112 c disposed in the receiving unit 109 by a parallel beam. Then, the signal light (wavelength λ 3) from the fiber end 102 a is reflected by the first WDM filter 115 and enters the PD 105.

  The second lenses 112a to 112c are held and fixed in the respective units, and are aligned by adjusting the mounting position with respect to the mounting surface of the housing 101 when each unit is mounted, so that the optical axis is fixed. First, the position of the first lens 111 and the sleeve 106 that accommodates and holds the optical fiber 102 is adjusted, and the fiber end 102a is positioned. The alignment between the fiber end 102a and the first LD 103 is performed by position adjustment (x, y) of the first transmission unit 107. The alignment between the fiber end 102 a and the second LD 104 is performed by adjusting the position (x, y) of the second transmission unit 108. The alignment between the fiber end 102a and the PD 105 is performed by position adjustment (x, y) of the receiving unit 109.

  However, the optical coupling between the fiber end and each lens by the parallel beam described above has a large coupling loss due to a lateral displacement (x, y) orthogonal to the optical axis, and the coupling loss can be suppressed to 0.2 dB or less. , High-precision alignment with a positional deviation of ± 3 μm or less is required, making adjustment difficult and labor intensive. Then, the following examination about the method of comprising two sets of lenses indicated by patent documents 1 with a condensing lens was performed.

  FIG. 11 shows a test result of coupling loss of optical coupling due to misalignment between the optical fiber and the lens during assembly (position misalignment in x and y directions perpendicular to the optical axis) when two condenser lenses are used. FIG. In the test, as shown in FIG. 11A, the separation distance between the first condenser lens and the second condenser lens is 5.13 mm, and the work distance between the first condenser lens and the fiber end is two. The work distance between the second condenser lens and the LD was 0.84 mm and 0.27 mm. Then, the first condenser lens was displaced in the x and y directions perpendicular to the optical axis, and the coupling loss at each position was measured. As a result, as shown in FIG. 11B, the positional deviation was ± 50 μm or less, the coupling loss was 0.6 dB or less, the positional deviation was ± 30 μm or less, and the coupling loss was 0.2 dB or less.

  On the other hand, FIG. 12 is a diagram showing a test result of coupling loss of optical coupling due to positional deviation between the optical fiber and the lens (positional deviation in the x and y directions perpendicular to the optical axis) during assembly by the parallel beam described in FIG. It is. In the test, as shown in FIG. 12A, the separation distance between the collimating lens and the objective lens is 5.0 mm, the work distance between the collimating lens and the fiber end is 1.762 mm, and the work distance between the objective lens and the LD is It was set to 0.297 mm. Then, the collimating lens was displaced in the x and y directions orthogonal to the optical axis, and the coupling loss at each position was measured. As a result, as shown in FIG. 12B, the positional deviation was ± 5 μm or less, the coupling loss was 0.5 dB or less, the positional deviation was ± 3 μm or less, and the coupling loss was 0.2 dB or less.

  From the above results, the optical fiber and the optical element are optically coupled using two condensing lenses, so that the coupling loss is comparable to that in the case of using two lenses optically coupled by parallel beams. , That tolerance can be increased by an order of magnitude. For this reason, adjustment is facilitated for coupling and fixing the units, and the workability of manufacturing can be improved.

  However, the beam waist position for optically coupling the two condensing lenses is in the casing constituting the optical module main body. This makes it difficult to adjust the optical axis direction in the Z direction, even though it is easy to adjust the axial displacement of the transmission / reception unit. In the receiving unit equipped with the PD, adjustment in the Z direction can be omitted, but in the transmitting unit equipped with the LD, adjustment in the Z direction is indispensable for efficiently transmitting the signal light to the optical fiber.

  The present invention has been made in view of the above-described circumstances. An optical module that enables adjustment of an axis deviation with an appropriate adjustment allowance and can easily adjust the optical axis direction, and an optical module using the optical module. The purpose is to provide a data link.

An optical module according to the present invention is an optical module in which an optical fiber held by a sleeve and an optical element mounted on at least one transmission unit are optically coupled via a first condenser lens and a second condenser lens. The first condenser lens is mounted on the condenser unit, and the sleeve is fixed to one surface of the condenser unit. The transmission unit is equipped with a second condensing lens, and is fixed to a joint fixing surface of the condensing unit different from the one surface of the condensing unit via a joint sleeve. One of the beam waist position of the first focusing lens is located on the end face of the optical fiber, the other beam waist position of the first focusing lens is on the junction fixing surface, light of the second focusing lens Adjustment of the optical axis direction by the joint sleeve and adjustment of the optical axis on the joint fixing surface so that the beam waist position opposite to the element coincides with the beam waist position on the joint fixing surface of the first condenser lens. It is adjusted and fixed in the orthogonal direction .

Further, the image magnification of the previous SL first focusing lens, for example, it is a magnification. Then, an optical isolator may be disposed in the optical path between the second condensing lens and the optical fiber in the transmission unit, and a wavelength demultiplexing filter may be disposed in the condensing unit .

  According to the present invention, in order to suppress the coupling loss due to the lateral displacement of the optical fiber and the condensing lens to 0.2 dB or less, the accuracy is ± 30 μm or less, which is compared with the case of optical coupling with a parallel beam. The center accuracy is low and the adjustment work becomes easy. Further, since the beam waist position of the first condenser lens is the joint fixing surface of the transmission unit, the optical coupling position is clear and the adjustment in the optical axis direction can be easily performed.

It is a figure explaining embodiment of the optical module by this invention, and is an example provided with one transmission unit. FIG. 6 is a view showing another embodiment of the optical module according to the present invention. It is a figure which shows other embodiment with the optical module by this invention. It is a figure which shows other embodiment with the optical module by this invention. It is a figure which shows other embodiment with the optical module by this invention. It is a figure which shows other embodiment with the optical module by this invention. It is a figure which shows other embodiment with the optical module by this invention. It is a figure which shows other embodiment with the optical module by this invention. It is a figure which shows other embodiment with the optical module by this invention. It is a figure which shows other embodiment with the optical module by this invention. It is a figure which shows the coupling loss by the position shift by the optical coupling of a condensing lens. It is a figure which shows the coupling loss by the position shift by the optical coupling of a parallel beam. It is a figure explaining an example of the optical module by a parallel beam of a prior art.

  An outline of an optical module according to the present invention will be described. 1 to 5 are diagrams showing examples of an optical module for transmission provided with only one or more transmission units. In the figure, 10a to 10e are optical modules, 11 is a housing, 11a to 11e are light transmission holes, 12a to 12d are joint fixing surfaces, 13 is an optical fiber, 13a is an optical fiber end, and 14a to 14d are LDs (wavelength λa). ~ Λd), 16 is a sleeve, 17a to 17d are transmission units, 18 is a joint sleeve, 21 is a first condenser lens, 22a to 22d are second condenser lenses, 23 is an optical isolator, and 24a to 24c are wavelengths. A demultiplexing filter (WDM filter) is shown.

FIG. 1 is a diagram showing the simplest basic form of an optical module according to the present invention, which is an example of an optical module for transmission comprising one optical fiber and one transmission unit.
In this optical module 10a, a sleeve 16 that accommodates and holds an optical fiber 13 is bonded and fixed to one end of a casing 11 that constitutes a condensing unit, and signal light having a wavelength λa is emitted to the opposite end. The transmission unit 17a on which the LD 14a is mounted is joined and fixed. In the housing 11, a first condenser lens 21 having one beam waist position is disposed on an optical fiber end (end surface) 13a of the optical fiber 13, and is optically coupled through a light transmission hole 11e. The other beam waist position of the first condenser lens 21 is set so as to be on the joint fixing surface 12a to which the transmission unit 17a is joined and fixed.

  A second condensing lens 22a is arranged in the transmission unit 17a, and one beam waist position is located at the light emitting portion of the LD 14a, and the transmission unit 17a is fixed to the joint fixing surface 12a at the other beam waist position. In this state, it is set so as to be positioned in the vicinity of the bonding fixing surface 12a. The second condensing lens 22a is optically coupled to the first condensing lens 21 having a beam waist position on the cemented fixing surface 12a and the light transmitting hole 11a provided so as to include the cemented fixing surface 12a.

  It is desirable that an optical isolator 23 be disposed in the optical path between the optical fiber end 13a and the LD 14a. The optical isolator 23 may be disposed at any position in the optical path between the optical fiber end 13a and the LD 14a. For example, in addition to the space between the first condenser lens 21 and the transmission unit 17a in the housing 11, as shown by the chain line, the optical fiber end 13a and the first condenser lens 21 in the optical path in the transmission unit 17a. It can be arranged in the optical path between.

The housing 11 is made of metal, and the first condenser lens 21 is physically fixed by fitting into a predetermined position in the housing 11. The first condenser lens 21 is, for example, installed near the center of the housing 11 with an image magnification of “1”, and a sleeve 16 that houses and holds the optical fiber 13 at one end that is one surface of the housing 11. Is fixed. The sleeve 16 is adjusted (or physically positioned without adjustment) and fixed (adhered or welded) in the (x, y) direction on the attachment end surface of the end portion of the housing 11. The optical axis of the optical fiber 13 may be set to be offset by a predetermined amount with respect to the lens center.

After the sleeve 16, the first condenser lens 21, the optical isolator and the like are attached to the housing 11 as described above to form a light collecting unit, the housing 11 is attached to the other end different from the attachment end surface of the sleeve. The transmission unit 17a is joined and fixed. For example, the second condenser lens 22a mounted in the transmission unit 17a is formed of an aspherical lens having an image magnification of “6” and has a work distance (WD) of about 0.25 mm with the LD 14a. Used. The transmission unit 17a uses the joint sleeve 18 to adjust in the z direction in the optical axis direction, and adjusts in the (x, y) direction in the direction perpendicular to the optical axis on the joint fixing surface 12a of the housing 11. Align. This alignment can be performed by causing the LD 14a to emit light and detecting the output from the optical fiber 13.

In this case, the beam waist position of the first condenser lens 21 is set so as to be the joint fixing surface 12a when the first condenser lens 21 is mounted. Therefore, the beam waist position of the second condenser lens 22a mounted in the transmission unit 17a matches the beam waist position of the first condenser lens 21 with reference to the joint fixing surface 12a . Adjustment by the joint sleeve may be performed, and the above-described alignment in the x, y, and z directions can be accurately and easily performed because the position of the counterpart side to be aligned is determined. Note that the casing 11 and the transmission unit 17a are bonded and fixed by resin after alignment, or are welded and fixed by YAG laser or resistance welding.

In the optical module 10a configured as described above, the signal light (wavelength λa) from the LD 14a passes through the optical isolator 23 disposed in the optical path and is incident on the optical fiber end 13a.
According to the optical module of this example, the increase in coupling loss can be reduced by the positional deviation between the optical fiber 13 and the transmission unit 17a (second condenser lens 22a). If the positional deviation is within ± 30 μm, the coupling loss can be suppressed to within 0.2 dB. In the case of the parallel lens shown in FIG. 13, in order to keep the coupling loss within 0.2 dB, the positional deviation needs to be ± 3 μm or less.

  FIG. 2 shows an example of an optical module for transmission composed of one optical fiber and two transmission units for generating signal lights having different wavelengths. The optical module 10a in FIG. 1 is different from the transmission unit 17a. The transmission unit 17b having a different transmission wavelength is bonded and fixed to the side surface of the housing 11. In the optical module 10b of this example, as in the example of FIG. 1, a sleeve 16 that accommodates and holds the optical fiber 13 is bonded and fixed to one end of the housing 11, and the signal light having the wavelength λa is fixed to the opposite end. The transmission unit 17a mounted with the LD 14a that emits light is joined and fixed. Then, the transmission unit 17b on which the LD 14b that emits the signal light having the wavelength λb is mounted on the side surface of the housing 11 is bonded and fixed. An optical isolator 23 and a WDM filter 24a are arranged in the optical path in the housing 11.

  Also in this example, the optical isolator 23 may be disposed at any position in the optical path between the optical fiber end 13a and the LD 14a and LD 14b. For example, in addition to between the first condenser lens 21 and the WDM filter 24a, it can be arranged in the optical path between the optical fiber end 12a and the first condenser lens 21, as indicated by a chain line. Moreover, you may make it arrange | position separately in the transmission unit 17a and the transmission unit 17b, respectively.

  The optical path of the first condenser lens 21 is branched into a beam that passes through the WDM filter 24a and travels in the direction of the transmission unit 17a, and a beam that is bent 90 ° by the WDM filter 24a and travels in the direction of the transmission unit 17b. The waist positions are set on the respective joint fixing surfaces 12a and 12b. In the transmission unit 17b, the second condenser lens 22b is arranged in the same manner as the transmission unit 17a described in FIG. 1. One beam waist position is located at the light emitting portion of the LD 14b, and the other beam waist position is The transmission unit 17b is set so as to be positioned in the vicinity of the joint fixing surface 12b in a state where the transmission unit 17b is jointly fixed to the joint fixing surface 12b of the housing 11.

  The condensing lens 22b disposed in the transmission unit 17b is, for example, an aspherical lens having an image magnification of “3” and a work distance (WD) with the LD 14b of about 0.45 mm. The transmission unit 17b uses the joint sleeve 18 in the same manner as the transmission unit 17a to adjust in the z direction in the optical axis direction, and is made (x, y) by the flat joint fixing surface 12b on the side surface of the housing 11. Adjust to the direction, align and fix by adhesion or welding. This alignment can be performed by causing the LD 14b to emit light and detecting the output from the optical fiber 13.

  The transmission unit 17a is optically coupled through the light transmission hole 11a at the beam beam waist position of the first condenser lens 21 and the second condenser lens 22a as described with reference to FIG. 1, and the transmission unit 17b is similarly configured. The first condenser lens 21 and the second condenser lens 22b are optically coupled through the light transmission hole 11b at the mutual beam beam waist position. Then, the signal light (wavelength λa) from the LD 14a passes through the WDM filter 24a and the optical isolator 23 arranged in the optical path and enters the optical fiber end 13a, and the signal light (wavelength λb) from the LD 14b passes through the optical path. The light is reflected by the WDM filter 24a disposed therein, passes through the optical isolator 23, and enters the optical fiber end 13a.

  FIG. 3 is an example of a transmission optical module including one optical fiber and two LDs that generate signal lights having different wavelengths, as in the example of FIG. In this example, the transmission units 17b and 17c are arranged opposite to the side surface of the casing 11, and the optical module 10c for transmission in which the axial length of the casing 11 is shortened is configured. As in the example of FIG. 2, the optical module 10 c of this example has a sleeve 16 for housing and holding the optical fiber 13 bonded and fixed to one end of the housing 11, and a wavelength λb on one side of the housing 11. A transmission unit 17b mounted with an LD 14b that emits signal light is bonded and fixed.

  A transmission unit 17c mounted with an LD 14c that emits signal light having a wavelength λc is bonded and fixed to the opposite side surface. An optical isolator 23 and two WDM filters 24a and 24b are arranged in the optical path in the housing 11. Also in this example, the optical isolator 23 may be arranged at any position as long as it is in the optical path between the optical fiber end 13a and the LD 14b and LD 14c, as in the example of FIG.

  The optical path of the first condenser lens 21 is transmitted through the WDM filter 24b and bent by 90 ° by the WDM filter 24a and directed toward the transmission unit 17b, and bent by 90 ° by the WDM filter 24b and directed toward the transmission unit 17c. The beam waist position is set on each of the joint fixing surfaces 12b and 12c. In the transmission unit 17c, the second condenser lens 22c is arranged similarly to the transmission unit 17b described in FIG. 2, and one beam waist position is located at the light emitting portion of the LD 14c, and the other beam waist position is The transmission unit 17c is set so as to be positioned in the vicinity of the joint fixing surface 12c in a state where the transmission unit 17c is jointly fixed to the joint fixing surface 12c of the housing 11.

  Similarly to the transmission unit 17b, the transmission unit 17c uses the joint sleeve 18 to adjust in the z direction in the optical axis direction, and in the (x, y) direction at the flat joint fixing surface 12c on the side surface of the housing 11. Adjust to, and fix by adhesion or welding. This alignment can be performed by causing the LD 14c to emit light and detecting the output from the optical fiber 13.

  As described with reference to FIG. 2, the transmission unit 17b is optically coupled through the light transmission hole 11b at the beam beam waist positions of the first condenser lens 21 and the second condenser lens 22b, and the transmission unit 17c is similarly configured. The first condenser lens 21 and the second condenser lens 22c are optically coupled through the light transmission hole 11c at the mutual beam beam waist position. The signal light (wavelength λb) from the LD 14b is reflected by the WDM filter 24a disposed in the optical path, passes through the WDM filter 24b and the optical isolator 23, and enters the optical fiber end 13a. The signal light (wavelength λc) from the LD 14c is reflected by the WDM filter 24b disposed in the optical path, passes through the optical isolator 23, and enters the optical fiber end 13a.

  FIG. 4 is an example of a transmission optical module composed of one optical fiber and three LDs that generate signal light having different wavelengths. The optical module 10a in FIG. 1 and the optical module c in FIG. 3 are combined. is there. In the optical module 10d of this example, a sleeve 16 that accommodates and holds an optical fiber 13 is bonded and fixed to one end of a housing 11, and an LD 14a that emits signal light having a wavelength λa is mounted on the opposite end. The unit 17a is joined and fixed. Then, a transmission unit 17b mounted with an LD 14b that emits signal light having a wavelength λb and a transmission unit 17c mounted with an LD 14c that emits signal light having a wavelength λc are arranged oppositely on the side surface of the housing 11 and fixed by bonding. The

  In the optical path in the housing 11, an optical isolator 23 and two WDM filters 24a and 24b are arranged as in the example of FIG. Also in this example, the optical isolator 23 may be disposed at any position in the optical path between the optical fiber end 13a and the LDs 14a, LD14c, and LD14c as in the example of FIG.

  The optical path of the first condenser lens 21 passes through the WDM filters 24a and 24b toward the transmission unit 17a, and passes through the WDM filter 24b and is bent by 90 ° by the WDM filter 24a toward the transmission unit 17b. The beam waist position is set on each of the joint fixing surfaces 12a, 12b, and 12c. The beam waist position is set to each of the joint fixing surfaces 12a, 12b, and 12c. As described above, the second condensing lenses 22a, 22b, and 22c are arranged in the transmission units 17a, 17b, and 17c, and light is transmitted at the beam waist position between the first condensing lens 21 and the respective joint fixing surfaces. The light is coupled through the transmission holes 11a, 11b, and 11c.

  Each transmission unit is aligned in the x, y, and z directions and fixed by bonding or welding. The signal light (wavelength λa) from the LD 14a passes through the WDM filters 24a and 24b and the optical isolator 23 arranged in the optical path and enters the optical fiber end 13a. The signal light (wavelength λb) from the LD 14b is reflected by the WDM filter 24a, passes through the WDM filter 24b and the optical isolator 23, and enters the optical fiber end 13a. The signal light (wavelength λc) from the LD 14c is reflected by the WDM filter 24b, passes through the optical isolator 23, and enters the optical fiber end 13a.

  FIG. 5 shows an example of a transmission optical module composed of one optical fiber and four LDs that generate signal lights having different wavelengths. In this example, a transmission unit 17d is further added to the optical module 10d of FIG. In the optical module 10e of this example, in addition to the transmission units 17a, 17b, and 17c, a joint fixing surface 12d that joins and fixes the transmission unit 17d on which the LD 14d that emits the signal light having the wavelength λd is mounted is formed. The bonding fixing surface 12d is shown in a form in which the wall surface position of the housing 11 is changed so that the beam waist position of the first condenser lens 21 becomes the bonding fixing surface 12d.

  The optical path of the first condenser lens 21 is branched in four directions by adding a WDM filter 24c in addition to the three directions in FIG. The beam waist position is set on each of the joint fixing surfaces 12a, 12b, 12c, and 12d. In the transmission units 17a, 17b, 17c, and 17d, second condensing lenses 22a, 22b, 22c, and 22d are arranged, and light is transmitted at the beam waist position between the first condensing lens 21 and the above-described joint fixing surfaces. It is optically coupled through the transmission holes 11a, 11b, 11c, and 11d.

  Each transmission unit is aligned in the x, y, and z directions and fixed by bonding or welding. Then, the signal light (wavelength λa) from the LD 14a passes through the WDM filters 24a, 24b, 24c and the optical isolator 23 arranged in the optical path, and enters the optical fiber end 13a. The signal light (wavelength λb) from the LD 14b is reflected by the WDM filter 24a, passes through the WDM filter 24b and the optical isolator 23, and enters the optical fiber end 13a. The signal light (wavelength λc) from the LD 14c is reflected by the WDM filter 24b, passes through the optical isolator 23, and enters the optical fiber end 13a. The signal light (wavelength λd) from the LD 14d is reflected by the WDM filter 24c, passes through the WDM filters 24a and 24b and the optical isolator 23, and enters the optical fiber end 13a.

  FIGS. 6 to 10 are examples of a single-fiber bidirectional optical module in which a receiving unit on which a PD is mounted is added to the above-described optical module for transmission to perform transmission and reception using a single optical fiber. In the figure, 10f to 10j are optical modules, 15a to 15c are PDs (wavelengths λe to λg), 19a to 19c are receiving units, 22f and 22g are second condenser lenses, and 24d to 24f are wavelength demultiplexing filters (WDM). Filter). Description of other reference numerals is omitted by using the same reference numerals as those used in FIGS.

  Unlike the transmission unit, the receiving unit does not require strict alignment in the optical axis direction. Usually, the optical axis direction in the z direction is physically positioned in advance, and only the axial deviation in the x and y directions is performed. Is adjusted. For this reason, it is not necessary to set the beam waist position of the first condenser lens 21 to be the joint fixing surface of the unit in the above-described joint fixing of the transmission unit. However, in the reception unit as well as the transmission unit, the beam waist position of the first condenser lens 21 may be on the joint fixing surface, and the adjustment in the optical axis direction may be performed.

  The optical modules 10f and 10g shown in FIGS. 6 and 7 correspond to a form in which the transmission unit 17c of the transmission optical module 10d described in FIG. 4 is replaced with a reception unit 19a. The transmission units 17a and 17b and their optical path systems have already been described with reference to FIGS.

  The optical module 10 f shown in FIG. 6 is formed by bonding and fixing a receiving unit 19 a on which a PD 15 a that receives signal light having a wavelength λe is mounted to the side surface of the housing 11. This receiving unit 19a does not have a condensing lens in the unit, but directly receives signal light by the first condensing lens 21 installed in the housing 11 of the condensing unit. The receiving unit 19a is adjusted and aligned in the (x, y) direction with a flat joint fixing surface 12c on the side surface of the housing 11, and is fixed by adhesion or welding. This alignment can be performed by sending monitor light from the optical fiber 13 and detecting the output by the PD 15a.

  In the optical path of the first condenser lens 21, a WDM filter 24d for bending the received light by 90 ° and reflecting it to the receiving unit 19a is disposed. Further, in the optical path between the transmission units 17 a and 17 b, the optical isolator 23 is individually mounted on each unit, and the WDM filter 24 a is mounted in the housing 11. In the receiving unit 19a, the signal light (wavelength λe) from the optical fiber end 13a passes through the first condenser lens 21 and is reflected and received by the WDM filter 24d arranged in the optical path. The signal light (wavelength λa) from the LD 14a passes through the optical isolator 23 and the WDM filters 24a and 24d arranged in the optical path and enters the optical fiber end 13a. The signal light (wavelength λb) from the LD 14b is reflected by the optical isolator 23 and the WDM filter 24a, passes through the WDM filter 24d, and enters the optical fiber end 13a.

  The optical module 10g shown in FIG. 7 is an example in which the installation position of the optical isolator 23 is different from that of the optical module 10f shown in FIG. In this example, the optical isolators 23 are arranged between the WDM filters 24a and 24d, and the number of optical isolators 23 can be reduced compared to the example of FIG. The signal light (wavelength λa) from the LD 14a is transmitted in the order of the WDM filter 24a, the optical isolator 23, and the WDM filter 24d arranged in the optical path, and enters the optical fiber end 13a. Similarly, the signal light (wavelength λb) from the LD 14b is reflected by the WDM filter 24a, then passes through the optical isolator 23 and the WDM filter 24d, and enters the optical fiber end 13a.

  The optical module 10h shown in FIG. 8 differs from the optical module 10g in FIG. 7 in the configuration of the receiving unit. The receiving unit 19a shown in FIGS. 6 and 7 is a unit that does not have a condensing lens in the unit. However, the receiving unit 19b of this example is mounted with a PD 15b that receives signal light having a wavelength λf. Has a second condenser lens 22f. One beam waist position of the second condenser lens 22 f is set at the light receiving portion of the PD 15 b, and the other beam waist position is set so as to match the beam waist position of the first condenser lens 21.

  For example, the second condenser lens 22f arranged in the receiving unit 19b is formed of an aspherical lens having an image magnification of “2” and has a work distance (WD) of about 1 mm with respect to the PD 15b. . Similar to the receiving unit 19a of FIGS. 6 and 7, this receiving unit 19b also does not require adjustment in the optical axis direction, and is made in the (x, y) direction by the flat joint fixing surface 12c on the side surface of the housing 11. Adjust and align, and fix by bonding or welding. This alignment can be performed by sending monitor light from the optical fiber 13 and detecting the output by the PD 15b. In the receiving unit 19b, the signal light (wavelength λf) from the optical fiber end 13a is reflected by the WDM filter 24e disposed in the optical path, and is collected and received by the second condenser lens 22e. The

9 and 10 show transmission / reception light having one optical fiber, one transmission LD that generates signal light, and two reception PDs that respectively receive signal light having different wavelengths from the outside. It is an example of a module.
The optical module 10i shown in FIG. 9 corresponds to a configuration in which the transmission unit 17b is replaced with a reception unit 19c with respect to the optical module 10h of FIG. However, the optical isolator 23 is arranged between the transmission unit 17a and the WDM filter 24a so as not to enter the optical path of the reception unit 19c.

  The receiving unit 19c is mounted with a PD 15c that receives the signal light having the wavelength λg, and has a second condenser lens 22g in the unit as in the receiving unit 19b. One beam waist position of the second condenser lens 22g is positioned at the light receiving portion of the PD 15c, and the other beam waist position is aligned with the beam waist position (bonding fixing surface 12b) of the first condenser lens 21. Is set as follows.

  As the second condenser lens 22g arranged in the reception unit 19c, a lens having a different image magnification or the like can be used from the second condenser lens 22f of the reception unit 19b. Further, this receiving unit 19c is also adjusted in the (x, y) direction with the joint fixing surface 12b flattened on the side surface of the casing 11, and is adjusted and bonded or welded without adjusting in the optical axis direction. To fix. This alignment can be performed by sending monitor light from the optical fiber 13 and detecting the output by the PD 15c. For this receiving unit 19c, the signal light (wavelength λg) from the optical fiber end 13a passes through the WDM filter 24e disposed in the optical path, is reflected by the WDM filter 24f, and is reflected by the second condensing. The light is condensed and received by the lens 22g.

  An optical module 10j illustrated in FIG. 10 corresponds to a configuration in which the transmission unit 17a is replaced with a reception unit 19c with respect to the optical module 10h illustrated in FIG. However, the optical isolator 23 is arranged in the transmission unit 17b so as not to enter the optical path of the reception unit 19c. The receiving unit 19c is the same as that described with reference to FIG. 9, and is used to receive signal light having a wavelength λg different from that of the receiving unit 19b. The receiving unit 19c is an extension of the first condenser lens 21 in the housing 11. Fixed to the joint.

  In this example, the signal light (wavelength λg) from the optical fiber end 13a passes through the WDM filter 24e and the WDM filter 24a disposed in the optical path, and is collected by the second condenser lens 22g, and is collected by the PD 15c. Received light. The transmission unit 17b transmits the signal light (wavelength λb) from the LD 14b through the optical isolator 23, is reflected by the WDM filter 24a, passes through the WDM filter 24e, and is incident on the optical fiber end 13a.

  When the above-described optical module is mounted on an optical data link such as an optical transceiver, signal light can be stably transmitted and received, and a highly reliable optical data link can be provided.

DESCRIPTION OF SYMBOLS 10a-10j ... Optical module, 11 ... Housing | casing, 11a-11d ... Light transmission hole, 12a-12d ... Bonding fixing surface, 13 ... Optical fiber, 13a ... Optical fiber end, 14a-14d ... LD (wavelength (lambda) a- (lambda) d) 15 ... PD (λe to λg), 16 ... Sleeve, 17a to 17d ... Transmission unit, 18 ... Joint sleeve, 19a-19c ... Reception unit, 21 ... First condenser lens, 22a-22g ... Second collection Optical lenses, 23... Optical isolators, 24a to 24f, wavelength demultiplexing filters (WDM filters).

Claims (4)

An optical module in which an optical fiber held by a sleeve and an optical element mounted on at least one transmission unit are optically coupled via a first condenser lens and a second condenser lens ,
The first condenser lens is mounted on a condenser unit, and the sleeve is fixed to one surface of the condenser unit;
The transmission unit is mounted with the second condensing lens, and is fixed to a joint fixing surface of the condensing unit different from the one surface of the condensing unit via a joint sleeve,
There one of the beam waist position of the first focusing lens on the end face of the optical fiber, the other beam waist position of the first focusing lens is located in front Kise' engagement fixing surface,
The optical axis direction by the joint sleeve is such that the beam waist position of the second condenser lens opposite to the optical element coincides with the beam waist position on the joint fixing surface of the first condenser lens. And an optical module that is adjusted and fixed in a direction orthogonal to the optical axis on the joint fixing surface . The optical module according to claim 1 , wherein an image magnification of the first condenser lens is equal. The optical module according to claim 1 or 2 in an optical path, wherein the optical isolator is disposed between the second condenser lens and the optical fiber in the transmission unit. The optical module according to any one of claims 1 to 3 , wherein a wavelength demultiplexing filter is disposed in the condensing unit.

Images