JP2005183519A - Optical communication module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical communication module which can reduce both electrical and optical crosstalk between an optical element and a photodetector even if these two elements are stored in one and the same package in order to reduce the size. <P>SOLUTION: The optical communication module has such a structure that the photodetector 13 upon which the light from an optical fiber terminal 2 is incident and a light emitting element 14 for emitting the light which will be entered into the optical fiber terminal are stored in one and the same can 18, that the can is located in a housing 10 in such a manner that the photodetector and the light emitting element may face the optical fiber terminal, and that the photodetector and the light emitting element are optically shielded and electrically insulated from each other by an optical shield wall 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical communication module disposed in a terminal for transmitting and receiving optical signals in an optical communication system.

  2. Description of the Related Art Conventionally, in an optical communication system based on bidirectional transmission using light of different wavelengths, an optical module composed of a light receiving element, a light emitting element, or the like is disposed at an optical signal transmission / reception terminal, and each light transmitted and received is separated by a filter. An example of such a conventional optical module is shown in FIG. In the illustrated optical module, the light from the optical fiber 100 is collected by the lens 101, reflected by the beam splitter 102, and incident on the light receiving element 103 to demultiplex and monitor the received optical signal. The light from 104 passes through the beam splitter 102, is collected by the lens 101, and enters the optical fiber 100.

  In the conventional method described above, separation by a filter (beam splitter) is performed when transmitting and receiving light having different wavelengths. However, Patent Document 1 described below provides light that separates transmitted and received light by providing a diffraction grating on a lens. Disclose the module. That is, as shown in FIG. 5, the hologram optical element 111 is disposed between the support base 130 on which the semiconductor laser 110 and the photodiode 120 are mounted and the terminal 140 of the optical fiber 340, and the hologram optical element 111 is placed on one of the substrates. A diffraction grating 160 is formed on the surface, and a lens 170 is formed on the other surface of the substrate. According to the optical module as shown in FIG. 5, the size can be reduced and the cost can be reduced.

  However, when a filter is used as shown in FIG. 4, the transmitted light can be separated from the reflected light by 90 °, whereas in the case of a grating as shown in FIG. Since it is necessary to be in a state where there is no polarization dependency, it is possible to separate only within an angle of 0.05 radians in the spectrum of the different-order light, for example, the zero-order light and the first-order light. This separation angle corresponds to 1.5 mm when the distance from the diffraction grating is 30 mm. Thus, in the optical module using the grating as shown in FIG. 5, it is difficult to ensure a large separation angle. For this reason, in order to avoid an increase in the size of the optical module package, light emission from a semiconductor laser or the like is required. It is necessary to dispose the element and a light receiving element such as a photodiode at a spatially close distance.

Then, electrical and optical crosstalk between the light emitting element and the light receiving element becomes a problem. Generally, in order to prevent electrical and optical crosstalk (40 dB is required), the light emitting element and the light receiving element are usually housed in a can (CAN) type package. Yes, it is possible to use this can type light emitting element and light receiving element in the case of a filter type, but in the case of a type in which a grating is provided on the lens, it is possible to use a can type light emitting element and a light receiving element. It was difficult.
Japanese Patent Laid-Open No. 5-241049

  In view of the above-described problems of the prior art, the present invention provides an electrical and optical cross between a light emitting element and a light receiving element even when the light emitting element and the light receiving element are housed in the same package for miniaturization. An object of the present invention is to provide an optical communication module capable of reducing talk.

  In order to achieve the above object, a first optical communication module according to the present invention includes a light receiving element that receives light from an optical fiber terminal and a light emitting element that emits light incident on the optical fiber terminal. Accommodated in a can, the can is disposed in a housing such that the light receiving element and the light emitting element face the optical fiber terminal, and optically shields between the light receiving element and the light emitting element; It is electrically insulated.

  According to this optical communication module, the light receiving element and the light emitting element are disposed in the same can, and the light shielding element and the light receiving element are optically shielded and electrically insulated from each other. Thus, it is possible to reduce the electrical and optical crosstalk between the light emitting element and the light receiving element that emit and enter the optical fiber terminal.

  In the optical communication module, the light receiving element and the light emitting element are disposed on the same substrate, and an electrical insulating portion is provided between the light receiving element and the light emitting element, thereby providing an electrical connection between the light emitting element and the light receiving element. Crosstalk can be reduced.

  Further, by providing a light shielding wall for separating incident light and outgoing light between the light receiving element and the light emitting element, optical crosstalk between the light emitting element and the light receiving element can be reduced.

  In a second optical communication module according to the present invention, a light receiving element on which light from an optical fiber terminal is incident and a light emitting element that emits light incident on the optical fiber terminal are separately provided on a first substrate and a second substrate. And the light receiving element and the light emitting element are opposed to the optical fiber terminal, and the first substrate and the second substrate are disposed in the housing while being shifted in the optical axis direction of the optical fiber terminal. It is characterized by that.

  According to this optical communication module, since the first substrate on which the light receiving element is disposed and the second substrate on which the light emitting element is disposed are different substrates, electrical crosstalk between the light emitting element and the light receiving element is reduced. Can be reduced. In addition, since the first substrate and the second substrate are shifted in the optical axis direction of the optical fiber terminal, optical crosstalk between the light emitting element and the light receiving element can be reduced.

  In the optical communication module, by providing a light shielding member for separating incident light and outgoing light between the light receiving element and the light emitting element and the optical fiber terminal, the optical communication between the light emitting element and the light receiving element is achieved. Crosstalk can be effectively reduced.

  Further, the first substrate or the second substrate disposed on the side closer to the optical fiber terminal is provided with a light transmission portion, and the second substrate or the first substrate disposed on the far side An optical path can be formed between the optical fiber terminal and the optical transmission terminal via the light transmission part.

  In the first and second optical communication modules, by arranging a diffraction grating and a condenser lens between the optical fiber terminal and the light receiving element and the light emitting element, incident light to the light receiving element and Can be separated from the outgoing light.

  In this case, by forming the diffraction grating on the condensing lens, the number of components is reduced, and the alignment of the diffraction grating and the condensing lens becomes unnecessary, and the assembling property of the optical communication module is improved. The diffraction grating may be formed on one surface or both surfaces of the condenser lens. By forming the diffraction gratings on both sides of the condenser lens, it is possible to increase the diffraction angle without significantly reducing the diffraction efficiency in a region where the diffraction pitch is narrow.

  Further, it is preferable that the diffracted light diffracted by the diffraction grating is incident on the light receiving element and the zero-order light of the diffraction grating from the light emitting element is incident on the optical fiber terminal. Thereby, the axis alignment of a light emitting element and an optical fiber terminal becomes easy, and the assembly property of an optical communication module improves.

  In addition, the light receiving element includes a plurality of light receiving portions, and is configured such that diffracted light having different diffraction angles by the diffraction grating is incident on each light receiving portion according to the diffraction angles, whereby a plurality of light having different wavelengths is formed. The signal can be received.

  According to the optical communication module of the present invention, it is possible to reduce electrical and optical crosstalk between the light emitting element and the light receiving element even when the light emitting element and the light receiving element are housed in the same package for miniaturization. Can do.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  <First Embodiment>

  FIG. 1 is a perspective view showing the inside of the optical communication module according to the first embodiment in a vertically divided state. FIG. 2 is a perspective view (a) showing a specific configuration in which the light receiving element and the light emitting element of FIG. 1 are accommodated in the same can, and a perspective view (b) showing a half state.

  As shown in FIG. 1, the optical communication module according to the first embodiment includes a condensing lens 11 that is disposed in the vicinity of the end 2 of the optical fiber 1 and has a diffraction grating 16 formed on the lens surface on the end 2 side. The light receiving element 13 on which the light flux from the condenser lens 11 is incident, the light emitting element 14 that emits the light flux so as to be incident on the condenser lens 11, and the light receiving element 13 and the light emitting element 14 are arranged on the same plane. A casing 10 includes a disk-shaped substrate 15, a light shielding wall 12 provided so as to isolate and optically shield the light receiving element 13 and the light emitting element 14 and to extend toward the condenser lens 11 on the substrate 15. It is provided in a cavity 17 formed inside. An electric insulating portion is provided between the light receiving element 13 and the light emitting element 14 in the disk-shaped substrate 15 as shown in FIG.

  The optical communication module of FIG. 1 is configured to be elongated as a whole in the optical axis direction P in which the optical fiber 1 extends. The optical fiber 1 can be connected to an optical cable network of an optical communication system, is held through the cylindrical holding body 3, and its end 2 is exposed at the end face of the holding body 3. The holding body 3 is partially held so as to be inserted into a cavity in the housing 10.

  The diffraction grating 16 of the condensing lens 11 is close to the end 2 of the optical fiber 1, the light beam from the end 2 of the optical fiber 1 is diffracted by the diffraction grating 16, and the first-order diffracted light is reflected by the condensing lens 11. It is condensed on the light receiving element 13. Further, a light beam emitted from the light emitting element 14 at a wavelength different from the wavelength of the light beam condensed on the light receiving element 13 is transmitted through the diffraction grating 16 through the condensing lens 11 and becomes the zero-order light at the end 2 of the optical fiber 1. It is focused on. As described above, the incident light is diffracted primary light and the outgoing light is zero-order light, so that the axis alignment between the light emitting element 14 and the end 2 of the optical fiber 1 is facilitated, and the assembly of the optical communication module is facilitated. improves.

  The substrate 15 and the light shielding wall 12 are disposed in a cylindrical can 18, and the light receiving element 13 and the light emitting element 14 on the substrate 15 are accommodated in the can 18. The light receiving element 13 is made of, for example, a photodiode, and the light emitting element 14 is made of, for example, a laser diode. Both of them are formed on the substrate 15 at a predetermined distance away from the central axis of the optical fiber 1.

  The light receiving element 13 and the light emitting element 14 are electrically connected to a plurality of terminals 19 provided so as to protrude from the substrate 15 to the outside of the can 18. The can 18 is fixed to the end of the housing 10 so that the light receiving element 13 and the light emitting element 14 accommodated are opposed to the end 2 of the optical fiber 1.

  Further, the light shielding wall 12 formed between the light receiving element 13 and the light emitting element 14 in the can 18 can reliably separate the incident light to the light receiving element 13 and the emitted light from the light emitting element 14, It is possible to reliably prevent the light emitted from the light emitting element 14 from entering the light receiving element 13.

  The optical communication module shown in FIG. 1 can be applied to an optical communication system that transmits optical signals having different wavelengths according to the wavelength division multiplexing method. For example, the optical communication module is used in a device terminal such as a user's personal computer. On the other hand, a plurality of terminals 19 are inserted into an insertion port of a connection device such as a router and connected to a personal computer or the like.

  According to the optical communication module of FIG. 1, when the input optical signal transmitted in the optical fiber 1 is emitted from the end portion 2, the first-order diffracted light diffracted and refracted by the diffraction grating 16 at a predetermined diffraction angle is collected. An electric signal which is condensed on the light receiving element 13 by the lens 11 and converted by the light receiving element 13 is output from the terminal 19.

  On the other hand, light emitted from the light emitting element 14 at a wavelength different from the wavelength of the light incident on the light receiving element 13 is incident on the condenser lens 11, passes through the diffraction grating 16, and is collected at the end 2 of the optical fiber 1 as zero order light. The light is transmitted and transmitted as an output optical signal in the optical fiber 1.

  As described above, optical signals having different wavelengths are transmitted in both the upstream and downstream directions within the same optical fiber 1 by the optical communication module of FIG. Is possible.

  As described above, the optical communication module of FIG. 1 can accommodate the light receiving element 13 and the light emitting element 14 in the same can 18 to be compact, and the can 18 and the condensing lens 11 on which the diffraction grating 16 is formed. By disposing in the housing 10 away from the end portion 2 of the optical fiber 1 in the optical axis direction P, it is possible to separate the incident light and the emitted light, and achieve miniaturization and cost reduction. .

  Even if the distance between the light receiving element 13 and the light emitting element 14 on the substrate 15 is relatively short due to the above-described miniaturization, the light shielding wall 12 on the substrate 15 is incident when an optical signal is transmitted / received. Since the light and the emitted light are reliably separated and the light from the light emitting element 14 is prevented from entering the light receiving element 13, the electrical and optical crosstalk between the light emitting element and the light receiving element is reduced. be able to. For this reason, stable optical communication is possible.

  Further, by forming the diffraction grating 16 on the condensing lens 11 and integrating the two, the number of parts is reduced, the alignment of both is not required, and the assembly of the optical communication module is improved. The diffraction grating 16 may be formed on the lens surface of the condenser lens 11 opposite to the end 2 of the optical fiber 1. Further, by forming diffraction gratings on both lens surfaces of the condenser lens 11, the diffraction angle can be increased. Further, by forming a spectral diffraction grating on one of the lens surfaces of the condenser lens 11 and forming an elliptical pattern diffraction grating on the other, the coupling efficiency in the optical communication module can be improved.

  Next, a specific configuration of the light emitting element and the light receiving element in FIG. 1 will be described with reference to FIG. As shown in FIGS. 2A and 2B, the light receiving element 13 and the light emitting element 14 are accommodated in a can 18 and blocked by a light shielding wall 12 provided upright from a substrate 15 in the can 18. Yes.

  As shown in FIG. 2A, the light receiving element 13 includes a plurality of light receiving portions 13a, 13b, and 13c arranged in an array, and diffracted light beams having different diffraction angles by the diffraction grating 16 are arranged in accordance with the diffraction angles. The light is incident on the light receiving portions 13a, 13b, and 13c.

  2B, the light receiving element 13 is formed on the light receiving element region 15a provided on the substrate 15, and an electrically insulating resin is provided between the light receiving element region 15a and the substrate 15 inside the substrate 15. An electrically insulating portion 15b made of a material is provided.

  The light emitting element 14 is provided at the bottom of a hole 12 a formed in a substantially semicircular mortar shape on the wall surface of the light shielding wall 12. For this reason, even if the light emitting element 14 is arrange | positioned at the bottom part of the hole 12a, there is no possibility that the light from the light emitting element 14 may be scattered.

  On the substrate 15, a monitor light-receiving element 14 a made of a photodiode or the like is disposed for receiving light from the light-emitting element 14. By feeding back the light reception signal of the monitor light receiving element 14a, the light emission amount of the light emitting element 14 is controlled to be constant.

  As described above, the light receiving element 13 is provided by the light shielding wall 12 that shields the light receiving element 13 and the light emitting element 14 within the can 18 and the electrical insulating portion 15b that electrically isolates the light receiving element 13 and the light emitting element 14 within the substrate 15. The optical and electrical crosstalk between the LED and the light emitting element 14 can be effectively reduced.

  In addition, light having different wavelengths from the end portion 2 of the optical fiber 1 in FIG. 1 changes in diffraction angle in accordance with each wavelength at the diffraction grating 16 and enters each of the light receiving portions 13a to 13c. For this reason, the wavelengths of the optical multiplexed signal are, for example, 1.31 μm for the emission light wavelength λ 0 from the light emitting element 14, and λ 1 = 1.47 μm for the light incident from the end 2 of the optical fiber 1, λ 2 = 1. .49 μm and λ3 = 1.51 μm (see FIG. 6A described later), a plurality of optical signals having different wavelengths can be received separately by the light receiving units 13a to 13c. By performing downstream wavelength division multiplexing (WDM) communication in this way, various data, such as digital television broadcasts, moving images, still images, audio, digital data communications, etc., carried on the optical signal of each wavelength can be converted into a single optical signal. Can be received through fiber.

  <Second Embodiment>

  FIG. 3 is a perspective view showing the inside of the optical communication module according to the second embodiment in a vertically divided manner.

  As shown in FIG. 3, the optical communication module according to the second embodiment includes a condensing lens 31 that is disposed near the end 2 of the optical fiber 1 and has a diffraction grating 36 formed on the lens surface on the end 2 side. And the light receiving element 33 on which the light flux from the condensing lens 31 is incident, and the light flux is emitted so as to be incident on the condensing lens 31, and is disposed farther away than the light receiving element 33 with respect to the end 2 of the optical fiber 1. The light shielding member disposed between the light receiving element 33 and the condensing lens 31 so as to optically separate and shield the incident light to the light emitting element 34 and the light incident on the light receiving element 13 and the light emitted from the light emitting element 14. 32 in a cavity 37 formed inside the housing 30.

  The optical communication module of FIG. 3 is configured to be elongated as a whole in the optical axis direction P in which the optical fiber 1 extends. The optical fiber 1 can be connected to an optical cable network of an optical communication system, is held through the cylindrical holding body 3, and its end 2 is exposed at the end face of the holding body 3. The holding body 3 is partially held so as to be inserted into the cavity 37 in the housing 30.

  The light shielding member 32 is configured in a cylindrical shape (barrel shape) with a partition wall portion 32 a provided in the middle. The partition wall portion 32 a includes a through hole 32 b through which incident light to the light receiving element 33 passes and a light emitting element 34. Through-hole 32c through which the emitted light passes.

  The light receiving element 33 is made of, for example, a photodiode, and is disposed on the first substrate 35 at a position that is decentered from the central axis of the optical fiber 1 while facing the end 2 of the optical fiber 1. The first substrate 35 is formed in a disc shape and integrally with the light shielding member 32, and is disposed so as to be inserted into the cavity 37. Further, the first substrate 35 is formed such that the transmitted light 40 passes through the light beam emitted from the light emitting element 34 at a position deviated from the central axis of the optical fiber 1 opposite to the light receiving element 33.

  The light emitting element 34 is made of, for example, a laser diode, and is disposed on a disc-shaped second substrate 38 facing the end 2 of the optical fiber 1 and decentered from the central axis of the optical fiber 1. The light receiving element 33 and the light emitting element 34 are electrically connected to a plurality of terminals 39 provided so as to protrude from the second substrate 38 to the outside.

  The second substrate 38 on which the light emitting element 34 is arranged is formed integrally with a cylindrical can 42. The can 42 is fixed so as to be inserted into the cavity 37 of the housing 30, and a plurality of terminals 39 protrude from the second substrate 38 to the outside. A disc 41 is provided at the tip of the cavity 37 of the can 42, and a lens 43 is disposed on the disc 41 at a position that is eccentric from the optical axis of the optical fiber 1 and through which light emitted from the light emitting element 34 passes. Has been. Light emitted from the light emitting element 34 is condensed by the lens 43 so as to pass through the transmission hole 40 of the first substrate 35.

  The transmission hole 40 of the first substrate 35 is configured to have a relatively small diameter so that the emitted light is collected by the lens 43 into the transmission hole 40, so that the emitted light is difficult to enter the light receiving element 33. Become.

  The diffraction grating 36 of the condensing lens 31 is close to the end 2 of the optical fiber 1, the light beam from the end 2 of the fiber 1 is diffracted by the diffraction grating 36, and the first-order diffracted light is received by the condensing lens 31. It is condensed on the element 13. Further, a light beam emitted from the light emitting element 34 at a wavelength different from the wavelength of the light beam condensed on the light receiving element 33 is transmitted through the diffraction grating 36 via the lens 43 and the condensing lens 31, and is optical fiber as 0th order light. 1 is focused on the end 2 of the first. As described above, the incident light is diffracted primary light and the outgoing light is zero-order light, which facilitates the axis alignment between the light emitting element 34 and the end 2 of the optical fiber 1 and facilitates the assembly of the optical communication module. improves.

  In addition, the first substrate 35 provided with the light receiving element 33 is disposed close to the end 2 of the optical fiber 1 in the optical axis direction P, and the second substrate 38 provided with the light emitting element 34 is disposed on the optical fiber 1. Since the light-receiving element 33 and the light-emitting element 34 are separated in the optical axis direction P because they are arranged far away from the end 2 in the optical axis direction P, optical crosstalk between them can be reduced. Further, the second substrate 38 provided with the light emitting element 34 is covered with the disc 41, and no light is emitted from other than the lens 43, and the light receiving element 33 does not face the light emitting element 34. Light emitted from 34 hardly enters the light receiving element 33, and optical crosstalk between the light emitting element 34 and the light receiving element 33 can be reduced. Furthermore, the light shielding member 32 can reliably separate the light incident on the light receiving element 13 and the light emitted from the light emitting element 14, so that optical crosstalk can be further reduced.

  Since the first substrate 35 and the second substrate 38 are different members and are spaced apart from each other, electrical crosstalk between the light emitting element 34 and the light receiving element 33 can be reduced.

  The optical communication module of FIG. 3 can be applied to an optical communication system that transmits optical signals with different wavelengths by the wavelength division multiplexing method, as in FIG. While the fiber 1 is connected to an optical cable network of an optical communication system, a plurality of terminals 39 are inserted into an insertion port of a connection device such as a router and connected to a personal computer or the like.

  According to the optical communication module of FIG. 3, when the input optical signal transmitted in the optical fiber 1 is emitted from the end 2, the first-order diffracted light diffracted and refracted by the diffraction grating 36 at a predetermined diffraction angle is collected. The lens 31 passes through the through hole 32 b of the light shielding member 32 and is condensed on the light receiving element 33, and an electric signal converted by the light receiving element 13 is output from the terminal 19.

  On the other hand, the light emitted from the light emitting element 34 at a wavelength different from the wavelength of the light incident on the light receiving element 33 passes through the transmission hole 40 of the first substrate 35 and the through hole 32c of the light shielding member 32 by the lens 43 and is condensed. The light enters the lens 31, passes through the diffraction grating 36, is condensed on the end 2 of the optical fiber 1 as zero-order light, and is transmitted as an output optical signal in the optical fiber 1.

  As described above, optical signals having different wavelengths are transmitted in both the upstream and downstream directions in the same optical fiber 1 by the optical communication module of FIG. Is possible.

  As described above, in the optical communication module of FIG. 3, the light receiving element 33 and the light emitting element 34 are arranged apart from each other in the optical axis direction P. And the emitted light can be separated, and miniaturization and cost reduction are achieved.

  Further, for the downsizing described above, the distance in the direction orthogonal to the central axis of the optical fiber between the optical path of the incident light to the light receiving element 33 and the optical path of the outgoing light from the light emitting element 34 is relatively short. Even when the optical signal is transmitted / received, the light shielding member 32 reliably separates the incident light and the emitted light, and reliably prevents the light from the light emitting element 34 from entering the light receiving element 33, Since the light receiving element 33 and the light emitting element 34 can be electrically and reliably insulated, electrical and optical crosstalk between the light emitting element 34 and the light receiving element 33 can be reduced. For this reason, stable optical communication is possible.

  Further, by forming the diffraction grating 36 on the condensing lens 31 and integrating them, the number of parts is reduced, and the alignment of both is not required, and the assembling property of the optical communication module is improved. The diffraction grating 36 may be formed on the lens surface of the condenser lens 31 opposite to the end 2 of the optical fiber 1. Further, by forming diffraction gratings on both lens surfaces of the condenser lens 31, the diffraction angle can be increased. Further, by forming the spectral diffraction grating on one of the lens surfaces of the condenser lens 31 and forming the elliptical diffraction grating on the other, the coupling efficiency in the optical communication module can be improved.

  As described above, the best mode for carrying out the present invention has been described. However, the present invention is not limited to these, and various modifications are possible within the scope of the technical idea of the present invention. For example, in FIGS. 1 and 2 (a) and 2 (b), the light shielding wall 12 may protrude from the can 18 and be configured to be longer, which increases the light shielding effect.

  In FIG. 3, a light emitting element may be disposed on the first substrate 35 and a light receiving element may be disposed on the second substrate 38.

  6A and 6B show a modification of the optical communication module shown in FIG. 3. The light receiving element 33 includes a plurality of light receiving portions 33a arranged in an array as shown in FIG. 6B. , 33b, 33c, and diffracted light beams having different diffraction angles by the diffraction grating 36 are incident on the light receiving portions 33a, 33b, 33c according to the diffraction angles.

  Further, the light receiving element 33 is accommodated in a relatively small first can 49 provided in the cylindrical lens barrel 32 ′, and the condenser lens is passed through a light transmission hole 49 a provided on the upper surface of the first can 49. Light from 31 enters the light receiving element 33. In FIG. 6B, a light shielding member is constituted by the partition wall portion 32a, the through hole 32b, the through hole 32c, the first can 49, and the light transmitting hole 49a, and the incident light to the light receiving element 33 and the light emitting element 34 are used. It is possible to optically separate the light emitted from the light and shield it more effectively.

  In FIG. 6, the transmission hole 40 through which the light emitted from the light emitting element of FIG. 3 passes is omitted. Further, a terminal 35 a for taking out an electric signal of the light receiving element 33 from the substrate 35 of the first can 49 extends.

  As shown in FIGS. 6A and 6B, light having different wavelengths from the end portion 2 of the optical fiber 1 is changed in diffraction angle in accordance with each wavelength by the diffraction grating 36, and the light receiving portions 33 a to 33 c respectively. Incident. Therefore, each wavelength of the optical multiplexed signal is, for example, 1.31 μm at the emission light wavelength λ 0 from the light emitting element 34, and the wavelengths of light incident from the end 2 of the optical fiber 1 are λ 1 = 1.47 μm, λ 2 = 1.49 μm and λ3 = 1.51 μm, but a plurality of optical signals having different wavelengths can be separately received by the light receiving units 33a to 33c. By performing downstream wavelength division multiplexing (WDM) communication in this way, various data, such as digital television broadcasts, moving images, still images, audio, digital data communications, etc., carried on the optical signal of each wavelength can be converted into a single optical signal. Can be received through fiber.

It is a perspective view which shows the inside of the optical communication module by 1st Embodiment vertically. FIG. 2 is a perspective view (a) showing a specific configuration in which the light receiving element and the light emitting element of FIG. 1 are accommodated in the same can, and a perspective view (b) showing a half state. FIG. 3 is a perspective view showing the inside of the optical communication module according to the second embodiment in a vertically divided manner. It is sectional drawing which shows the conventional optical module which isolate | separates each light of transmission and reception with a filter. It is sectional drawing which shows another conventional optical module which provides a diffraction grating on a lens, and isolate | separates each light of transmission and reception. It is a figure which shows the modification of the optical communication module of FIG. 3, and is a perspective view (a) which shows the inside of an optical communication module vertically, and a perspective view (b) which expands and shows the principal part.

Explanation of symbols

1 optical fiber 2 end (optical fiber terminal)
DESCRIPTION OF SYMBOLS 10 Case 11 Condensing lens 12 Light shielding wall 13 Light receiving element 13a, 13b, 13c Multiple light-receiving part 14 Light emitting element 15 Substrate 15b Electrical insulation part 16 Diffraction grating 18 Can 19 Terminal 30 Case 31 Condensing lens 32 Light shielding member 32a Partition part 32b Through hole 32c Through hole 33 Light receiving element 33a, 33b, 33c Multiple light receiving part 34 Light emitting element 35 First substrate 36 Diffraction grating 37 Cavity 38 Second substrate 39 Terminal 40 Through hole 40 Transmission hole (light transmission) Part)
41 disc 42 can 43 lens 49 first can P optical axis direction

Claims (11)

A light receiving element on which light from an optical fiber terminal enters and a light emitting element that emits light incident on the optical fiber terminal are housed in the same can,
The can is disposed in a housing such that the light receiving element and the light emitting element face the optical fiber terminal,
An optical communication module, wherein the light receiving element and the light emitting element are optically shielded and electrically insulated. The optical communication module according to claim 1, wherein the light receiving element and the light emitting element are disposed on the same substrate, and an electrical insulating portion is provided between the light receiving element and the light emitting element. The optical communication module according to claim 1, wherein a light shielding wall for separating incident light and outgoing light is provided between the light receiving element and the light emitting element. A light receiving element on which light from an optical fiber terminal is incident and a light emitting element that emits light incident on the optical fiber terminal are separately disposed on the first substrate and the second substrate,
The light receiving element and the light emitting element are opposed to the optical fiber terminal, and the first substrate and the second substrate are arranged in the housing while being shifted in the optical axis direction of the optical fiber terminal. Optical communication module. The optical communication module according to claim 4, wherein a light shielding member that separates incident light and outgoing light is provided between the light receiving element and the light emitting element and the optical fiber terminal. The first substrate or the second substrate disposed on the side closer to the optical fiber terminal is provided with a light transmission portion, and the second substrate or the first substrate disposed on the far side and the light 6. The optical communication module according to claim 4, wherein an optical path is formed between the optical fiber terminal and a transmission part. The optical communication module according to claim 1, wherein a diffraction grating and a condenser lens are disposed between the optical fiber terminal, the light receiving element, and the light emitting element. The optical communication module according to claim 7, wherein the diffraction grating is formed on the condenser lens. 9. The optical communication module according to claim 8, wherein the diffraction grating is formed on one surface or both surfaces of the condenser lens. The diffracted light diffracted by the diffraction grating is incident on the light receiving element, and zero-order light of the diffraction grating from the light emitting element is incident on the optical fiber terminal. The optical communication module according to 8 or 9. 11. The light receiving element according to claim 7, wherein the light receiving element includes a plurality of light receiving portions, and diffracted lights having different diffraction angles by the diffraction grating are incident on the light receiving portions according to the diffraction angles. The optical communication module according to claim 1.

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