WO2024053467A1 - Optical transmission module - Google Patents

Abstract

The purpose of the present disclosure is to provide an optical transmission module which is small-sized and highly integrated and which can perform demultiplexing and multiplexing across multiple wavelengths.　An optical transmission module (100) according to the present disclosure has: a first lens part (30) which refracts and focuses transmitted light between an optical fiber (90) and the first lens part; a second lens part (60) disposed on the optical axis of the first lens part (30) so as to face the first lens part; a receptacle substrate (51) having a contact plug (52) which positions an end surface of the optical fiber at the focal point of the second lens part (60) and which connects the optical fiber; a first light guide body (11) disposed on a surface, of the first lens part (30), not facing the second lens part; a demultiplexing/multiplexing part (20) which is disposed on a surface, of the first light guide body (11), not having the first lens part disposed therein and which demultiplexes or multiplexes the transmitted light of the first lens part; and a plurality of photoelectric elements (21a, 21b) which are disposed in the demultiplexing/multiplexing part (20) and which performs at least one of light emission to the first lens part and light reception from the first lens part, via the demultiplexing/multiplexing part and the first light guide body.

Description

optical transmission module

The present disclosure relates to an optical transmission module that converts an electrical signal into an optical signal or an optical signal into an electrical signal for high-speed optical communication.

In recent years, digital networking has progressed rapidly, and its importance as a common infrastructure for society is increasing. The central data center will go beyond its role as a mere server and will be equipped with supercomputers and artificial intelligence (AI), contributing to society through the realization of virtual reality called digital twins. It is expected more and more.

However, it is predicted that Moore's law will come to an end due to the limits of miniaturization of semiconductor devices, and further speeding up of computers is reaching its limit. Therefore, the importance of high-speed optical communication that can be multiplexed is increasing in order to increase the speed by parallelizing many computers and to increase the scale of AI networks.

There are many methods for high-speed optical communication, but the cheapest photoelectric device used for this uses a laser called VCSEL (Vertical Cavity Surface Emitting Laser) as the light source and a PD (Photo Diode) as the light receiving part. It is something to do. In the VCSEL method, light is emitted and incident perpendicularly to a substrate on which a light emitting element and a light receiving element are mounted.

Also, like many high-speed optical communication systems, the VCSEL system can multiplex signal lights of multiple wavelengths to increase speed and make it bidirectional.
Conventionally, the following technology has been disclosed as a configuration for performing multi-wavelength demultiplexing and multiplexing in order to multiplex such multi-wavelength signal light.

Patent Document 1 describes one or more transmitting optical elements that transmit optical signals, one or more receiving optical elements that receive optical signals, one or more optical signals emitted from an optical fiber, and An optical transmission module that has an optical member that converts the optical path of one or more optical signals that enter the optical fiber having a different wavelength from the optical signal, and has a fitting part that is mechanically fitted to the optical fiber. has two or more inclined surfaces with respect to the optical axis of the optical fiber, and one of the inclined surfaces is provided with an optical functional member that transmits a part or almost all of each optical signal or reflects a part of each optical signal. , a reflective surface for reflecting an optical signal is formed on the other one of the inclined surfaces, a fiber lens is provided on the end surface of the fiber facing the optical fiber, and the optical functional member is formed of a transmitting optical element and a receiving optical element. An optical transmission module is disclosed in which a demultiplexing characteristic is set so that an optical signal transmitted from a transmitting optical element does not leak into the transmitting optical element of the other party depending on the arrangement.

Normally, when using a general VCSEL as a transmitting optical element in a two-way communication type optical transmission module that simultaneously transmits or receives data using a single optical fiber, crosstalk (for example, if the VCSEL has a wavelength different from the oscillation wavelength) (e.g., an optical signal may be incident). Therefore, in order to prevent the optical transmission module from malfunctioning, it is necessary to appropriately design an optical filter that transmits or reflects a portion or almost all of each optical signal. However, by adopting the configuration as described in Patent Document 1, it is possible to prevent the occurrence of crosstalk as much as possible and provide an optical transmission module and an optical transmission system that do not malfunction.

Patent Document 2 describes the structure of a module used for optical transmission, including a main body substrate having a front surface and a back surface, an optical connector having a resin substrate, and a first transparent substrate disposed between the resin substrate and the main body substrate. a heat source element disposed between the resin substrate and the back surface of the main body substrate and electrically connected to the main body substrate; One or more wirings that propagate heat generated by the substrate to the main substrate, and a first space that is formed between the resin substrate and the first transparent substrate and propagates the heat generated by the heat source element and the first transparent substrate. An optical transmission module is disclosed that includes: a second space that is formed between the heat source element and the back surface of the main body substrate, and that transmits heat generated by the heat source element and the first transparent substrate.

According to the optical transmission module of the present disclosure, since the first space for suppressing heat propagation and the second space for adding a function for heat propagation are formed, the resin substrate and the second space are formed. It is possible to suppress deformation due to heat and deterioration of optical coupling efficiency between the first transparent substrates.

Japanese Patent Application Publication No. 2009-251375 JP 2015-60097 Publication

However, the optical transmission module described in Patent Document 1 performs multiplexing of multiple wavelengths in an optical member, so each of the light sources or light receiving parts that constitute the optical function part has a correspondingly sized lens or This requires a reflecting mirror or filter. Therefore, there is a problem in that there is a limit to reducing the size of the optical transmission module, and high integration is difficult.

In addition, since multiple wavelengths are combined using optical members, the shape and structure of the optical member becomes complex, and it is necessary to change the shape and structure of the optical function part depending on the wavelength, the number of photoelectric elements to be multiplexed, etc. This poses a problem in that it is difficult to standardize and share optical members.

Additionally, the optical transmission module described in Patent Document 1 has problems in its manufacturing method, such as the fact that the optical receptacle must be attached after adjustment by active alignment to attach the optical receptacle.

The optical transmission module described in Patent Document 2 discloses a solution to this problem. However, since the optical transmission module uses an optical receptacle manufactured by the same manufacturing method as the optical transmission module described in Patent Document 1, positional displacement due to heat may become a problem. For this reason, when optical receptacles become larger due to the increase in wavelengths, there is a problem in that the possibility of positional displacement due to heat increases.

The present disclosure has been made in view of such problems, and aims to provide a compact and highly integrated optical transmission module that enables multiple wavelength demultiplexing and multiplexing.

The present disclosure has been made to solve the above-mentioned problems, and a first aspect thereof is:
a first lens portion that refracts and focuses transmitted light between the optical fiber;
a second lens section disposed on the optical axis of the first lens section and facing the first lens section;
a receptacle board having a plug for connecting the optical fiber, which positions the end face of the optical fiber at the focal point of the second lens part;
a first light guide disposed on a surface of the first lens section that does not face the second lens section;
a demultiplexing/combining part disposed on a surface of the first light guide where the first lens part is not disposed, and demultiplexing or combining light transmitted through the first lens part;
A plurality of lights disposed in the demultiplexing/combining section and performing at least one of emitting light to the first lens section and receiving light from the first lens section via the demultiplexing/multiplexing section and the first light guide. a photoelectric element,
This is an optical transmission module with

Further, in the first aspect, the demultiplexing/multiplexing section is laminated into two layers, an upper stage and a lower stage, and the upper division/multiplexing part reflects light in a predetermined wavelength band so that one of the photoelectric elements The light in a predetermined wavelength band is split/combined, and the light of other wavelengths is transmitted from the upper splitting/combining section to the lower splitting/multiplexing section. may be configured to separate and combine light in predetermined wavelength bands for each of the plurality of photoelectric elements.

In the first aspect, the demultiplexing/multiplexing section includes a first reflective/transmissive section having a first wavelength selective film formed on an inclined surface having a predetermined inclination angle on the optical axis of the first lens section. ,
a second reflective/transmissive part or a reflective mirror having a second wavelength selective film formed on an inclined surface having a predetermined inclination angle and arranged in parallel with the first reflective/transmissive part;
a third light guide arranged in parallel between the first reflective transmitting section and the second reflective transmitting section;
A second light guide may be provided in parallel at a position opposite to the third light guide with the first reflective/transmissive portion interposed therebetween.

Furthermore, in the first aspect, the first wavelength selection film may be configured to transmit light in a predetermined wavelength band and reflect light in other wavelengths.

Furthermore, in the first aspect, the second wavelength selective film may be configured to reflect light in a predetermined wavelength band and transmit light in other wavelengths.

Further, in the first aspect, the plurality of photoelectric elements disposed in the demultiplexing/multiplexing section are capable of emitting or receiving light in the same wavelength band, and some of the photoelectric elements among the plurality of photoelectric elements are capable of emitting or receiving light in the same wavelength band. It may be configured such that one photoelectric element is used regularly, and some of the other photoelectric elements are used as a spare, and furthermore, the regular use and the spare can be switched.

Further, in the first aspect, the third light guide is formed of a high refractive index resin, and the second light guide is formed of a low refractive index resin, so that each of the plurality of photoelectric elements is It may be arranged at the focal point of one lens section.

Further, in the first aspect, the first reflective transmitting section is formed in a plane mirror shape with respect to the incident light, and the second reflective transmitting section is formed in a concave mirror shape with respect to the reflected light from the first reflective transmitting section. Each of the plurality of photoelectric elements may be disposed at a focal point of the first lens portion.

Further, in the first aspect, the first reflective transmitting section is formed in a convex mirror shape with respect to the incident light, and the second reflective transmitting section is formed in a concave mirror shape with respect to the reflected light from the first reflective transmitting section. Each of the plurality of photoelectric elements may be disposed at a focal point of the first lens portion.

Furthermore, in the first aspect, the demultiplexing/combining section may have wiring connecting the photoelectric elements.

Furthermore, in the first aspect, the photoelectric element may be soldered to the wiring.

Furthermore, in the first aspect, the wiring may include a solder ball for connection to an external circuit.

Further, in the first aspect, any of the transmitted light between the second lens part and the first lens part disposed on the optical axis to face the second lens part is The light may be configured to be parallel light.

Further, in the first aspect, a plurality of second lens portions are arranged to face each other on the optical axis of each of the plurality of first lens portions, each of which transmits the demultiplexed and multiplexed light;
a reflecting mirror that reflects the transmitted light of each of the plurality of second lens parts,
The receptacle board has a plurality of sockets for connecting a plurality of optical fibers corresponding to a plurality of reflected lights or incident lights on the reflecting mirror, and the optical fibers connected and fixed to the respective sockets. The light may be configured to be focused on the end face of the fiber.

By adopting the above aspect, it is possible to provide a compact and highly integrated optical transmission module that enables multiple wavelength demultiplexing and multiplexing.

FIG. 2 is a front view of the basic form of the first embodiment of the optical transmission module according to the present disclosure. FIG. 2 is a side view of the basic form of the first embodiment of the optical transmission module according to the present disclosure. It is a front view of the 1st modification of 1st Embodiment of the optical transmission module based on this indication. FIG. 7 is a front view of a second modification of the first embodiment of the optical transmission module according to the present disclosure. FIG. 7 is a front view of a third modification of the first embodiment of the optical transmission module according to the present disclosure. FIG. 2 is an explanatory diagram (part 1) of the manufacturing process of the photoelectric conversion unit of the first embodiment of the optical transmission module according to the present disclosure. FIG. 3 is an explanatory diagram (Part 2) of the manufacturing process of the photoelectric conversion unit of the first embodiment of the optical transmission module according to the present disclosure. FIG. 3 is an explanatory diagram (Part 3) of the manufacturing process of the photoelectric conversion unit of the first embodiment of the optical transmission module according to the present disclosure. FIG. 4 is an explanatory diagram (part 4) of the manufacturing process of the photoelectric conversion unit of the first embodiment of the optical transmission module according to the present disclosure. FIG. 5 is an explanatory diagram (part 5) of the manufacturing process of the photoelectric conversion unit of the first embodiment of the optical transmission module according to the present disclosure. FIG. 6 is an explanatory diagram (part 6) of the manufacturing process of the photoelectric conversion unit of the first embodiment of the optical transmission module according to the present disclosure. FIG. 7 is an explanatory diagram (part 7) of the manufacturing process of the photoelectric conversion unit of the first embodiment of the optical transmission module according to the present disclosure. FIG. 8 is an explanatory diagram (Part 8) of the manufacturing process of the photoelectric conversion unit of the first embodiment of the optical transmission module according to the present disclosure. FIG. 3 is a front view of a photoelectric conversion section of a second embodiment of an optical transmission module according to the present disclosure. FIG. 7 is a front view of a photoelectric conversion section of a third embodiment of an optical transmission module according to the present disclosure. FIG. 7 is a front view of a photoelectric conversion section of a fourth embodiment of an optical transmission module according to the present disclosure. FIG. 7 is an explanatory diagram of a difference in refractive index and an optical path in a fourth embodiment of the optical transmission module according to the present disclosure. FIG. 7 is a front view of a photoelectric conversion section of a fifth embodiment of an optical transmission module according to the present disclosure. FIG. 7 is a front view of a photoelectric conversion section of a sixth embodiment of an optical transmission module according to the present disclosure. It is a front view of the photoelectric conversion part of the modification of 6th Embodiment of the optical transmission module based on this indication. It is a top view of the photoelectric conversion part of 7th Embodiment of the optical transmission module based on this indication. It is a side view of the photoelectric conversion part of 7th Embodiment of the optical transmission module based on this indication. FIG. 6 is a plan view and a front view of a comparative example for explaining the effect of the demultiplexing/multiplexing section of the optical transmission module according to the present disclosure. 24 is a side view of the comparative example shown in FIG. 23. FIG. FIG. 6 is a plan view and a front view of a photoelectric conversion section for explaining the effect of the demultiplexing/multiplexing section of the third modification of the first embodiment shown in FIG. 5. FIG. 26 is a side view of the photoelectric conversion section shown in FIG. 25. FIG. FIG. 21 is a plan view and a front view for explaining the effect of the demultiplexing/combining section of the modified example of the sixth embodiment shown in FIG. 20; FIG. 3 is a comparative explanatory diagram summarizing the effects of the demultiplexing/multiplexing section of the optical transmission module according to the present disclosure.

Next, embodiments for implementing the optical transmission module according to the present disclosure (hereinafter referred to as "embodiments") will be described in the following order with reference to the drawings. In the following drawings, the same or similar parts are designated by the same or similar symbols. However, the drawings are schematic and the proportions of dimensions of each part do not necessarily match the actual ones. Furthermore, it goes without saying that the drawings include portions with different dimensional relationships and ratios.
1. First embodiment of optical transmission module according to the present disclosure 2. Manufacturing process of the first embodiment of the optical transmission module according to the present disclosure 3. Second embodiment of optical transmission module according to the present disclosure 4. Third embodiment of optical transmission module according to the present disclosure 5. Fourth embodiment of optical transmission module according to the present disclosure 6. Fifth embodiment of optical transmission module according to the present disclosure 7. Sixth embodiment of optical transmission module according to the present disclosure 8. Seventh embodiment of optical transmission module according to the present disclosure 9. Effects of the demultiplexing/multiplexing section of the optical transmission module according to the present disclosure

<1. First embodiment of optical transmission module according to the present disclosure>
[Configuration of basic form of first embodiment]
FIG. 1 is a front view of a basic form of a first embodiment of an optical transmission module 100 according to the present disclosure. Similarly, FIG. 2 is a side view thereof. As shown in FIGS. 1 and 2, the optical transmission module 100 includes an optical receptacle section 50 having a substantially rectangular receptacle substrate 51 as a base, and an optical receptacle section 50 disposed on the lower surface, which is one surface of the optical receptacle section 50. The photoelectric conversion section 10 is arranged to face the two lens sections 60.
The photoelectric conversion section 10 includes a first light guide 11 formed in a substantially rectangular shape, a first lens section 30 disposed on its upper surface, and photoelectric elements 21a and 21b disposed on its lower surface. It has a multiplexing section 20. The second lens section 60 and the first lens section 30 are generally configured to be disposed facing each other on the same optical axis LA2.

Below, the basic configuration of the first embodiment of the optical transmission module 100 will be described in more detail. In the following description, the optical receptacle section 50 side will be referred to as the upper side, and the photoelectric conversion section 10 side will be referred to as the lower side. Further, the number of optical paths of the photoelectric elements 21a, 21b, etc. that perform photoelectric conversion is assumed to be one circuit, two circuits, etc.

The optical receptacle section 50 is a device for connecting an optical fiber 90 of an optical cable connected to an optical communication line, and for exchanging optical signals with the photoelectric conversion section 10. The optical receptacle section 50 has a plug 52 for connecting an optical fiber 90 to one end of a substantially rectangular receptacle substrate 51 having translucent properties. The optical fiber 90 is then inserted into the connector 52 and fixedly connected thereto.

A reflecting mirror 53 is formed on the upper surface of the optical receptacle portion 50 and is centered on the optical axis LA1 of the optical fiber 90 and is inclined at a predetermined angle with respect to the vertical direction. The reflecting mirror 53 reflects the incident light traveling along the optical axis LA1 from the optical fiber 90 in the direction of the optical axis LA2, and enters the photoelectric conversion unit 10 via the second lens 60. Alternatively, the light beams L1 and L2 traveling along the optical axis LA2 from the photoelectric conversion unit 10 via the second lens 60 are reflected to change the optical path from the optical axis LA2 to the optical axis LA1. The reflected light from the reflecting mirror 53 travels along the optical axis LA1 and is focused on the end face 91 of the optical fiber 90. In this way, the reflecting mirror 53 is a device that changes the direction of light.

Therefore, when changing the direction of the optical axis to a right angle, it is preferable to set the inclination angle of the reflecting mirror 53 to 45 degrees. Note that the light ray L1 here refers to light in a predetermined wavelength band that is received or emitted by the photoelectric element 21a, and the light ray L2 refers to light in a predetermined wavelength band that is received or emitted by the photoelectric element 21b. This also applies to the cases of light rays L3 and L4.

The second lens section 60 disposed on the lower surface of the optical receptacle section 50 is formed of, for example, a convex lens. It is arranged perpendicularly to the optical axis LA2 and with its optical center on the optical axis LA2. The second lens section 60 refracts the reflected light from the reflecting mirror 53 and converts it into parallel light, or refracts the parallel light from the photoelectric conversion section 10 to enter the reflecting mirror 53, and converts the reflected light into parallel light. The light is focused on the end face 91 of the optical fiber 90. Therefore, the end surface 91 of the optical fiber 90 is arranged at the focal point of the second lens section 60. Alternatively, the focal length of the second lens section 60 is set so that it is located at the end surface 91 of the optical fiber 90.

The photoelectric conversion unit 10 has a substantially rectangular transparent first light guide 11 as a base, and has a first lens part 30 on the upper surface of the first light guide 11, that is, the surface facing the second lens part 60. is disposed, and a demultiplexing/multiplexing section 20 is disposed on the lower surface of the first light guide 11, which is the back surface thereof.

The first lens section 30 is disposed on the same optical axis LA2, facing the second lens section 60 of the optical receptacle section 50. The first lens section 30 refracts the parallel light from the second lens section 60 with a predetermined refractive index and enters the first light guide 11, or refracts the parallel light from the second lens section 60 with a predetermined refractive index. The parallel light is refracted by the refractive index and enters the second lens section 60 . That is, the first lens section 30 is an optical element that refracts and focuses the light transmitted between it and the optical fiber 90.

The first lens section 30, like the second lens section 60, is formed of, for example, a convex lens. It is arranged perpendicular to the optical axis LA2 and with its optical center on the optical axis LA2.
The second lens section 60 and the first lens section 30 may both be convex lenses, and are not limited to a biconvex lens, a plano-convex lens, a concave-convex lens, or the like.

The first light guide 11 is an optical element that guides light between the first lens section 30 disposed on its upper surface and the demultiplexing/combining section 20 disposed on its lower surface. Therefore, the first light guide 11 is formed using a light-transmitting material. That is, the first light guide 11 is made of, for example, sapphire, glass, transparent plastic, or the like. Although sapphire is expensive, it has low optical loss over a wide frequency band, so it generates little heat even when light passes through it, making it ideal for use as a light guide.

As shown in FIG. 1, the demultiplexing/combining section 20 includes the fourth light guide 14 and the second reflective/transmissive section 23b (hereinafter referred to as "reflective/transmissive section 23b") at a predetermined interval from the left in this figure. ), the third light guide 13, the first reflective/transmissive section 23a (hereinafter referred to as the "reflective/transmissive section 23a"), and the second light guide 12 are arranged in parallel. That is, the third light guide 13 is arranged in parallel between the reflective/transmissive section 23a and the reflective/transmissive section 23b, and the second light guide 12 is arranged on the opposite side of the third light guide 13 with the reflective/transmissive section 23a in between. They are placed side by side. All of these have translucency and are made of the material forming the first light guide 11 or a material equivalent thereto.

The reflective/ transmissive parts 23a and 23b are formed into substantially inverted right triangles when viewed from the front, and have inclined surfaces 25a and 25b inclined at a predetermined angle on their oblique sides, which are right-angled opposite sides. A first wavelength selective film 24a (hereinafter referred to as "wavelength selective film 24a") is formed on the inclined surface 25a, and a second wavelength selective film 24b (hereinafter referred to as "wavelength selective film 24b") is formed on the inclined surface 25b. ) is formed. That is, the reflective/ transmissive parts 23a and 23b are optical elements in which wavelength selective films 24a and 24b are formed on inclined surfaces 25a and 25b of a predetermined angle.

The wavelength selection film 24a receives incident light from the optical fiber 90 along the optical axis LA2, transmits only the light ray L1 in a predetermined wavelength band in the direction of the optical axis LA2, and reflects light of other wavelengths. do. As a result, the transmitted light through the wavelength selection film 24a continues along the optical axis LA2 and enters the photoelectric element 21a.

Further, the direction of the optical path of the light reflected by the wavelength selection film 24a is changed from the optical axis LA2 to the optical axis LA3. The reflected light then travels along the optical axis LA3 and enters the wavelength selection film 24b. The wavelength selection film 24b reflects only the light beam L2 in a predetermined wavelength band, and transmits the other incident light. The optical path of the light beam L2 reflected by the wavelength selection film 24b is changed from the optical axis LA3 to the optical axis LA4. The light beam L2 whose optical path direction has been changed travels along the optical axis LA4 and enters the photoelectric element 21b.
Incidentally, the inclined surface 25b of the reflective/transmissive part 23b is used for the wavelength selection film 24a when the light traveling along the optical axis LA3 may be totally reflected or when the photoelectric element 21b is the light emitting element 211. There is no need to consider transmitting light like this. Therefore, in such a case, a reflecting mirror may be formed on the inclined surface 25b instead of the wavelength selection film 24b.
Similarly, in each embodiment described below, a reflecting mirror may be formed on the inclined surface 25b instead of the wavelength selection film 24b. Therefore, hereinafter, it will be described as a "wavelength selection film 24b" including the case where a reflecting mirror is formed. However, this applies in cases where there is a special mention in the description of each embodiment or in the case of a modification of the sixth embodiment described later.

Next, the light beam L1 emitted by the photoelectric element 21a travels along the optical axis LA2 in the opposite direction to the incident light, enters the wavelength selection film 24a, and is transmitted as it is. The light then finally enters the end face 91 of the optical fiber 90.

Further, the light ray L2 emitted by the photoelectric element 21b travels along the optical axis LA4 in the opposite direction to the incident light, enters the wavelength selection film 24b and is reflected, and the optical path of the reflected light ray L2 starts from the optical axis LA4. The direction can be changed to optical axis LA3. The light ray L2 continues along the optical axis LA3, enters the wavelength selection film 24a, is reflected there, and the direction of the optical path of the reflected light ray L2 is changed from the optical axis LA3 to the optical axis LA2. Thereafter, the light ray L2 passes through the optical path opposite to that of the incident light and finally enters the end face 91 of the optical fiber 90.

As described above, the wavelength selection films 24a and 24b transmit or reflect light in a predetermined wavelength band, and have the function of a bandpass filter for the predetermined wavelength band. Further, the wavelength selection film 24a sequentially changes the optical path to the optical axes LA2, LA3, and LA4 by transmitting or reflecting incident light in a predetermined wavelength band. However, in order for the wavelength selection film 24b to reflect the incident light, it is necessary to allow at least the reflected light from the inclined surface 24a to travel straight through the third light guide 13 along the optical axis LA3. For this reason, it is preferable to set the inclination angle of the inclined surface 25a having the wavelength selection film 24a to 45 degrees.

The same applies to the inclination angle of the inclined surface 25b having the wavelength selection film 24b. Therefore, it is preferable that the inclination angles of the inclined surfaces 25a, 25b of the reflective/ transmissive parts 23a, 23b are both set to the above-mentioned 45 degrees.

A wiring 41 is formed on the lower surface of the demultiplexing/combining section 20 . The wiring 41 is, for example, an electrical connection formed of a conductive metal such as copper (Cu). As shown in FIG. 1 or 2, photoelectric elements 21a and 21b are soldered to the wiring 41 via solder balls 42. As shown in FIG.
Further, a solder ball 43 for connecting to the circuit board 40 is formed on the predetermined wiring 41 . Therefore, the optical transmission module 100 is connected to the circuit board 40 by soldering with the solder balls 43.

Here, the photoelectric elements 21a and 21b are a general term for the light receiving element 212 that converts an optical signal into an electrical signal, or the light emitting element 211 that converts an electrical signal into an optical signal. The light receiving element 212 is formed of, for example, a photodiode. Further, as the light emitting element 211, for example, a vertical cavity surface emitting laser called a VCSEL (Vertical Cavity Surface Emitting Laser) is used. VCSEL is a type of laser, and unlike a semiconductor laser, which emits light from the end face of an active layer formed on a substrate, it is characterized by resonating light in a direction perpendicular to the substrate surface and emitting light in a direction perpendicular to the substrate surface. It is.

Therefore, the incident light that has been refracted by the first lens section 30 and has traveled straight through the inside of the first light guide 11 along the optical axis LA2 is incident on the wavelength selection film 24a and transmitted through the wavelength selection film 24a. A light beam L1 in a predetermined wavelength band is incident on the photoelectric element 21a. Therefore, in order to collect and receive the incident light from the first lens section 30, the photoelectric element 21a is preferably disposed at the focal point of the first lens section 30.

Furthermore, the light beam L2 that has traveled straight along the optical axis LA4 is incident on the photoelectric element 21b. It is preferable that the photoelectric element 21b is disposed at the focal point of the first lens section 30, similarly to the photoelectric element 21a. However, as shown in FIG. 1, the optical path of the incident light that travels straight on the optical axis LA4 and enters the photoelectric element 21b is smaller than the optical path of the incident light that travels straight on the optical axis LA2 and enters the photoelectric element 21a. , the optical path length is increased by the length of the optical axis LA3.

As described above, since there is a difference in the optical path length of the optical axis LA3, when the photoelectric element 21a is arranged at the focal point position of the first lens section 30, the light condensed onto the photoelectric element 21b may become blurred. become. Similarly, if the photoelectric element 21b is disposed at the focal point of the first lens section 30, the light condensed onto the photoelectric element 21a will be blurred.

However, for convenience of explanation, in the drawings from FIG. 1 onward, the light rays L1, L2, etc. are depicted as traveling while widening or narrowing, but in reality, the light from the VCSEL travels approximately in a straight line. The light rays L1 and L2 do not widen or narrow greatly as shown in this figure. Further, the core diameter of the VCSEL/photodiode and the optical fiber 90 has a tolerance for the size of light condensation. Therefore, in practice, the blurring of light condensation is not a problem. Compensation for the difference in optical path length of the optical axis LA3 will be described in detail in the fourth embodiment, the fifth embodiment, and the sixth embodiment.

Note that unless otherwise mentioned, an example will be described in which the photoelectric element 21a is disposed at a position near the focal point of the first lens section 30, and the photoelectric element 21b is disposed at a position at the focal point of the first lens section 30. do. However, in actual practice, the focal point of the first lens section 30 may be located at the photoelectric element 21a, or at any position between the photoelectric element 21a and the photoelectric element 21b. may be set.

In addition, all of the photoelectric elements 21a and 21b soldered to the demultiplexing/combining section 20 via the wiring 41 may be light receiving elements 212, all of them may be light emitting elements 211, or all of them may be light receiving elements 211, or all of them may be light receiving elements 211, A combination of the element 212 and the light emitting element 211 may be used.
Furthermore, in the basic form of this embodiment, an example of the demultiplexing/combining section 20 having two photoelectric elements 21a and 21b has been described, but the number is not limited to two, and the same configuration as the photoelectric element 21b can be further added. By arranging them in parallel, it is possible to configure the demultiplexing/combining section 20 having a plurality of photoelectric elements 21a, 21b, etc. The same applies to other embodiments and modifications thereof described below.

The basic configuration of the first embodiment according to the present disclosure is as described above. Further, the optical transmission module 100 according to the present disclosure is naturally used while being housed in a predetermined storage case that has a light-shielding property, but the shape and the like are not particularly limited, so a description thereof will be omitted. The same applies to each embodiment below.

[Basic operation of the first embodiment]
Next, the operation of the basic form of the first embodiment will be explained in detail below based on FIG. 1 or FIG. 2.

(1) When both photoelectric elements are light-receiving elements The operation when both photoelectric elements 21a and 21b are light-receiving elements 212 and 212 was briefly explained in the basic configuration of the first embodiment, but it will be explained in detail again. explain.
When the photoelectric elements 21a and 21b are both light receiving elements 212, the optical transmission module 100 becomes a two-circuit reception-only module.

Here, the optical signal emitted from the optical fiber 90 includes all optical signals of various wavelengths transmitted from a communication device (not shown) to which the optical fiber 90 is connected. Therefore, the optical fiber 90 emits all light of these wavelengths from its end face 91. The emitted light travels within the receptacle substrate 51 along the optical axis LA1 and enters the reflecting mirror 53. The reflecting mirror 53 reflects all of these incident lights. Therefore, the optical path of the reflected light is redirected from the optical axis LA1 to the optical axis LA2.

The light traveling within the receptacle substrate 51 along the optical axis LA2 reaches the second lens section 60. An end surface 91 of the optical fiber 90 is arranged at the focal point of the second lens section 60. Therefore, the light emitted from the end face 91 of the optical fiber 90 becomes light having a predetermined solid angle and propagates while spreading. Then, by being refracted at the second lens section 60, the light becomes parallel light when it passes through the second lens section 60. The parallel light transmitted through the second lens section 60 enters the first lens section 30 of the photoelectric conversion section 10, which is disposed opposite to the second lens section 60 and on the same optical axis LA2.

The light incident on the first lens section 30 is refracted, and as shown in FIG. The light then travels inside the reflective/transmissive section 23a and enters the wavelength selection film 24a. Of the light incident on the wavelength selection film 24a, light rays L1 in a predetermined wavelength band are transmitted, and light of other wavelengths is reflected in a direction along the optical axis LA3.

The light beam L1 transmitted through the wavelength selection film 24a continues inside the second light guide 12 along the optical axis LA2 and enters the photoelectric element 21a. The photoelectric element 21a is arranged at a position near the focal point of the first lens section 30. Therefore, the light beam L1 is focused on the photoelectric element 21a. Since the light receiving element 212, which is the photoelectric element 21a, is formed of a photodiode, for example, electrons are excited by the focused light beam L1, and the optical signal is converted into an electrical signal.

This electrical signal is taken out and processed by a signal processing circuit or the like (not shown) formed on the circuit board 40 via the solder ball 42, wiring 41, and solder ball 43 of the demultiplexing/combining section 20.

On the other hand, the optical path of the light reflected by the wavelength selection film 24a is changed from the optical axis LA2 to the optical axis LA3. The reflected light then travels inside the reflective/transmissive section 23a and the third light guide 13 along the optical axis LA3, and is incident on the wavelength selection film 24b. Of the light incident on the wavelength selection film 24b, a light ray L2 in a predetermined wavelength band is reflected in a direction along the optical axis LA4, and incident light with other wavelengths is transmitted through the wavelength selection film 24b.

Since the photoelectric element 21b is located at the focal point of the first lens section 30, the light beam L2 reflected by the wavelength selection film 24b is focused on the photoelectric element 21b. Since the light-receiving element 212, which is the photoelectric element 21b, is formed of, for example, a photodiode, electrons in the light-receiving element 212 are excited by the focused light beam L2 and generate an electric signal.
This electrical signal is subjected to signal processing similarly to the photoelectric element 21a.
In the basic form of the first embodiment, when both the photoelectric elements 21a and 21b are the light receiving elements 212, they operate as described above and convert the received optical signals into electrical signals.

(2) When both photoelectric elements are light emitting elements Next, the case where both photoelectric elements 21a and 21b are light emitting elements 211 and 211 will be described in more detail.

If the photoelectric elements 21a and 21b are both light emitting elements 211 and 211, the optical transmission module 100 becomes a two-circuit transmission-only module. Here, a predetermined transmission signal is input from a signal processing circuit or the like (not shown) formed on the circuit board 40 to the wiring 41 via the solder ball 43, and is sent to the light emitting element which is the photoelectric element 21a via the solder ball 42. 211 is driven. Note that the drive circuit that drives the light emitting element 211 may be placed on either the wiring 41 or the circuit board 40.

The photoelectric element 21a is located near the focal point of the first lens section 30. Therefore, the light beam L1 in the predetermined wavelength band emitted from the photoelectric element 21a is emitted from a position near the focal point of the first lens section 30. The light beam L1 emitted by the photoelectric element 21a travels along the optical axis LA2 and is incident on the wavelength selection film 24a.

The wavelength selection film 24a transmits the light beam L1 in the predetermined wavelength band and reflects light in other wavelengths. However, in the case of a VCSEL, it is monochromatic light having a peak at a specific wavelength, and by setting it to emit light ray L1 in a predetermined wavelength band, only the light ray L1 is transmitted through the wavelength selection film 24a.

The light ray L1 that has passed through the wavelength selection film 24a continues along the optical axis LA2 through the reflection-transmission section 23a and the first light guide 11, and enters the first lens section 30. The light beam L1 in the predetermined wavelength band is refracted by the first lens section 30, and becomes substantially parallel light when transmitted through the first lens section 30. The substantially parallel light that has passed through the first lens section 30 enters the second lens section 60 as it is.

The parallel light incident on the second lens section 60 is refracted by the second lens section 60, travels within the receptacle substrate 51 along the optical axis LA2 while being focused, and enters the reflecting mirror 53. The reflecting mirror 53 reflects all of these light rays L1. Therefore, the optical path of the light beam L1 is changed from the optical axis LA2 to the optical axis LA1. The light beam L1 then travels along the optical axis LA1 and enters the end surface 91 of the optical fiber 90.

Here, the end face 91 of the optical fiber 90 is arranged at the focal point of the second lens section 60 as described above. Therefore, the light from the second lens section 60 is focused on the end surface 91 of the optical fiber 90. The light beam L1 of a predetermined wavelength band focused on the end face 91 of the optical fiber 90 enters the optical fiber 90 as it is and propagates.

Next, the photoelectric element 21b will be explained. The photoelectric element 21b is located at the focal point of the first lens section 30. Therefore, the light beam L2 emitted from the photoelectric element 21b is emitted from the focal point of the first lens section 30.

The light beam L2 in a predetermined wavelength band emitted by the photoelectric element 21b travels along the optical axis LA4 and is incident on the wavelength selection film 24b. The wavelength selection film 24b reflects the light beam L2 and transmits light of other wavelengths. However, in the case of VCSEL, as in the case of the photoelectric element 21a, the light is monochromatic light having a peak at a specific wavelength, and by setting it to emit light ray L2 in a predetermined wavelength band, the reflection of the wavelength selection film 24b The light becomes only the light ray L2.
The optical path of the light ray L2 reflected by the wavelength selection film 24b is changed from the optical axis LA4 to the optical axis LA3, travels inside the third light guide 13 along the optical axis LA3, and enters the wavelength selection film 24a. do.

As described above, the wavelength selection film 24a reflects light having a wavelength other than the light ray L1 of the emission wavelength of the photoelectric element 21a, so the light ray L2 from the photoelectric element 21b is reflected. Then, the optical path of the light beam L2 is changed from the optical axis LA3 to the optical axis LA2, travels along the optical axis LA2 through the reflective/transmissive part 23a and the first light guide 11, and enters the first lens part 30. incident. The light ray L2 is refracted by the first lens section 30, and becomes parallel light when it passes through the first lens section 30. Thereafter, the light beam is focused and incident on the end surface 91 of the optical fiber 90 via the same optical path as the light beam L1 of the photoelectric element 21a described above.
Note that the wavelength of the light beam L1 emitted from the photoelectric element 21a and the wavelength of the light beam L2 emitted from the photoelectric element 21b are different from each other, but may be the same wavelength.

(3) Case in which one of the photoelectric elements is a light emitting element and the other is a light receiving element Next, a case in which one of the photoelectric elements 21a, 21b is a light emitting element 211 and the other is a light receiving element 212 will be further described.

When one of the photoelectric elements 21a and 21b is a light emitting element 211 and the other is a light receiving element 212, the optical transmission module 100 becomes a two-circuit transmission/reception-only module. Here, either of the photoelectric elements 21a and 21b may be the light receiving element 212 or the light emitting element 211.
That is, when either the photoelectric element 21a or the photoelectric element 21b is the light receiving element 212, either the photoelectric element 21a or 21b described in "(1) When both photoelectric elements are light receiving elements" It operates in the same way as the light receiving element 212.

In addition, when either the photoelectric element 21a or the photoelectric element 21b is a light emitting element 211, the light emitting element 211 of the photoelectric elements 21a and 21b explained in "(2) When both photoelectric elements are light emitting elements" mentioned above It works the same way. That is, it is a combination of the operations of the light receiving element 212 and the light emitting element 211 described above. Therefore, the explanation will be omitted below.
In this way, the photoelectric elements 21a and 21b emit light to or receive light from the first lens section 30 via the demultiplexing/combining section 20 and the first light guide 11.

[Configuration of first modification of first embodiment]
Next, a first modification of the first embodiment of the optical transmission module 100 according to the present disclosure will be described. In the first modification of the first embodiment, as shown in FIG. 3, the optical fiber 90 is pulled out in the front direction. That is, in the basic form of the first embodiment, the drawing direction of the optical fiber 90 is directed toward the right side, but in the first modification, it is different from the basic form of the first embodiment in that it is configured to face the front. differ. Since the configuration other than the above is the same as the basic form of the first embodiment, the explanation will be omitted.

Note that the direction in which the optical fiber 90 is drawn out in the first modification is not limited to the front direction, and may be, for example, the back direction, the left side direction, the right direction at 45 degrees, or the like. In short, the direction in which the optical fiber 90 is drawn out may be any direction on the horizontal plane.

[Configuration of second modification of first embodiment]
Next, a second modification of the first embodiment of the optical transmission module 100 according to the present disclosure will be described. In the second modification of the first embodiment, as shown in FIG. 4, the optical fiber 90 is drawn out in the upward direction. That is, the second modification differs from the basic form of the first embodiment in that the optical fiber 90 is configured to be led out from above. Since the configuration other than the above is the same as the basic form of the first embodiment, the explanation will be omitted.
Note that the upward direction in this modification is not limited to the strict vertical direction.

[Configuration of third modification of first embodiment]
Next, a third modification of the first embodiment of the optical transmission module 100 according to the present disclosure will be described. As shown in FIG. 5, the third modification of the first embodiment is configured by arranging two optical transmission modules 100 shown in the first modification in parallel. That is, the third modification is different from the first modification in that it is configured to support multi-wavelength or multi-channel optical communication by configuring two optical transmission modules 100 shown in the first modification in parallel. This is different from the basic form, the first modification, or the second modification of the embodiment.

Note that since two optical transmission modules 100 are arranged in parallel, the portion corresponding to the fourth light guide 14 becomes the second light guide 12 of the photoelectric conversion section 10 of the adjacent optical transmission module 100. In addition, in order to prevent malfunction due to light leakage to the adjacent second light guide 12, a light shielding film 28 is provided at the boundary between the adjacent second light guide 12 and the reflective/transmissive part 23b, as shown in FIG. is forming. Since the configuration other than the above is the same as the basic form of the first embodiment, the explanation will be omitted.

Furthermore, although this modification shows an example in which two optical transmission modules 100 are arranged in parallel, the number is not limited to two, and any number of optical transmission modules 100 may be arranged in parallel. An example of multiple wavelengths exceeding two will be described later. In addition, in the description of each embodiment below, an example in which two optical transmission modules 100 are arranged in parallel will be explained in principle, but the number is not limited to two, and when two or more are arranged in parallel, is also applicable.

<2. Manufacturing process of the first embodiment of the optical transmission module according to the present disclosure>
Next, an example of the manufacturing process of the first embodiment of the optical transmission module 100 according to the present disclosure will be described.
First, as shown in FIG. 6, for example, a glass substrate 11A, which will become the first light guide 11, is prepared.

Next, as shown in FIG. 7, reflective/ transmissive parts 23a and 23b having a substantially right triangular shape with inclined sides 25a and 25b are provided on the upper surface of the glass substrate 11A, and a first lens part is provided on the lower surface of the glass substrate 11A. 30 are each molded by double-sided imprint. Imprint is a molding method in which resin or the like is pressed onto the glass substrate 11A using a so-called pressing die. The resin used for this is a translucent resin.

Next, as shown in FIG. 8, a resist 81 is applied to the upper surface of the glass substrate 11A except for the inclined surfaces 25a and 25b of the reflective and transmissive parts 23a and 23b. Then, wavelength selective films 24a and 24b are formed on the inclined surfaces 25a and 25b by vapor deposition. Furthermore, a reflecting mirror may be formed on the inclined surface 25b by vapor deposition instead of the wavelength selection film 24b.

Next, as shown in FIG. 9, the resist 81 is removed, and the third light guide 13 is placed between the reflective and transparent parts 23a and 23b, and the second light guide 12 and A fourth light guide 14 is formed. The second light guide 12, the third light guide 13, and the fourth light guide 14 are all made of a translucent resin. In addition, when compensating for the difference in the optical path length of the optical axis LA3, which is the difference in the optical path length between the photoelectric elements 21a and 21b, the third light guide 13 is raised to a height as described in the fourth embodiment below. It may be formed from a refractive index resin, and the second light guide 12 may be formed from a low refractive index resin.

Next, as shown in FIG. 10, wiring 41 having a predetermined pattern is formed on the surface on which the second light guide 12, third light guide 13, and fourth light guide 14 are formed. The wiring 41 is for joining the photoelectric elements 21a and 21b and the solder ball 43. Further, a signal processing circuit for the light receiving element 212, which is the photoelectric element 21a, 21b, a driving circuit for the light emitting element 211, etc. may be formed.

Next, as shown in FIG. 11, the photoelectric elements 21a and 21b are soldered to the wiring 41 using solder balls 42. Then, as shown in FIG. Solder bonding is performed by reflow. By performing reflow soldering, the photoelectric elements 21a and 21b can be automatically and accurately aligned by self-alignment due to the surface tension of the molten solder. Therefore, the photoelectric elements 21a and 21b can be arranged accurately and with high precision on the optical axes LA2 and LA4, respectively.
Next, a solder ball 43 for connecting the photoelectric conversion unit 10 to the circuit board 40 is bonded to a predetermined land of the wiring 41.

Next, as shown in FIG. 12, the glass substrate 11A is separated into individual pieces. As a result, the photoelectric conversion section 10 of the optical transmission module 100 is completed. Although this figure shows an example of the photoelectric conversion section 10 used in the basic form, the first modification, and the second modification of the first embodiment, the photoelectric conversion section 10 used in the third modification shown in FIG. It is also possible to separate the parts 10 into two pieces arranged side by side. Alternatively, two or more pieces may be placed side by side and then separated into pieces.

Next, as shown in FIG. 13, the photoelectric conversion section 10 is turned upside down and soldered to the circuit board 40 using the solder balls 43. Solder bonding is performed by reflow. Furthermore, the optical transmission module 100 of the first embodiment can be formed by combining it with the optical receptacle section 50 manufactured in a separate process. Note that the combination with the optical receptacle portion 50 may be performed before or after soldering to the circuit board 40.

Note that since the transmitted light between the second lens section 60 of the optical receptacle section 50 and the first lens section 30 of the photoelectric conversion section 10 is basically parallel light, the second lens section 60 and the first lens section The distance from the portion 30 is independent of the focal length of both. Therefore, the arrangement interval between the second lens section 60 and the first lens section 30 may be arbitrary. Therefore, as long as the optical axes LA2 of the two coincide with each other, there is no need to strictly align the distance between the two. Specifically, the incident light from the second lens section 60 to the first lens section 30 and the output light from either of the photoelectric elements 21a and 21b disposed at the focal point position of the first lens section 30, or as will be described later. The light emitted from the photoelectric elements 21a and 21b according to the fourth embodiment and the like becomes parallel light.

<3. Second embodiment of optical transmission module according to the present disclosure>
Next, a second embodiment of the optical transmission module 100 according to the present disclosure will be described. In this embodiment, as shown in FIG. 14, three photoelectric elements 21a, 21b, and 21c are arranged to configure an optical transmission module 100 including a three-circuit photoelectric conversion section 10.
That is, another demultiplexing/multiplexing section 70 is formed between the first light guide 11 and the demultiplexing/multiplexing section 20 described in the first embodiment, and three circuits of photoelectric elements 21a, 21b, and 21c are formed. This enables the demultiplexing and multiplexing of light.

Specifically, another demultiplexing/multiplexing section 70 is laminated between the first light guide 11 and the demultiplexing/multiplexing section 20 . The demultiplexing/multiplexing section 70 is provided with a reflective/transmissive section 73a on the optical axis LA2, which is a substantially right-angled triangle whose hypotenuse forms an inclined surface 75a, and which has a similar shape on the right side. A reflective/transmissive section 73b is provided. A second light guide 71 is disposed on the left side of the reflective/transmissive section 73a, and a third light guide 72 is disposed between the reflective/ transmissive sections 73a and 73b. In addition, wavelength selection films 74a and 74b are formed on the inclined surfaces 75a and 75b of the reflective and transmissive parts 73a and 73b, respectively. The wavelength selection film 74a reflects the light beam L3 having a predetermined emission wavelength or reception wavelength of the photoelectric element 21c, and transmits light having other wavelengths.

Here, a case where the photoelectric element 21c is the light receiving element 212 will be explained. Of the incident light traveling along the optical axis LA2, a light ray L3 in a predetermined wavelength band is reflected by the wavelength selection film 74a. The optical path of the light ray L3 reflected by the wavelength selection film 74a is changed from the optical axis LA2 to the optical axis LA5, and the light ray L3 travels along the optical axis LA5 and enters the wavelength selection film 74b. The wavelength selection film 74b reflects the light beam L3 in a predetermined wavelength band. However, since the wavelength selection film 74a reflects only the light ray L3 of the wavelength, a reflecting mirror that totally reflects the light ray L3 may be provided on the inclined surface 75b instead of the wavelength selection film 74b.

The optical path of the light ray L3 reflected by the wavelength selection film 74b is changed from the optical axis LA5 to the optical axis LA6, and the light ray L3 travels along the optical axis LA6 and passes through the second light guide of the demultiplexing/combining section 20. The light passes through the body 12 and enters the photoelectric element 21c. The photoelectric element 21c is arranged at a position near the focal point of the first lens section 30, as described in the basic form of the first embodiment. Therefore, the light beam L3 is focused on the light receiving element 212, which is the photoelectric element 21c, and is converted into an electrical signal.
If the photoelectric element 21c is the light emitting element 211, the optical path will simply be the opposite, so the explanation will be omitted.

On the other hand, the light transmitted through the wavelength selection film 74a enters the demultiplexing/combining section 20. The optical path after entering the demultiplexing/multiplexing unit 20 is the same as that described in the basic form of the first embodiment, and therefore the description thereof will be omitted. The same applies to the case of outputting from the demultiplexing/combining section 20. Further, the configuration other than the above is the same as that described in the basic form of the first embodiment, so the description will be omitted.

Since the second embodiment is configured as described above, it is possible to perform demultiplexing and multiplexing of light from three circuits. In addition, in FIG. 14, it has been explained that the optical transmission module 100 having three circuits of photoelectric elements 21a, 21b, and 21c can be formed. An optical transmission module 100 can also be formed.

That is, the upper division/multiplexing section 70 is further laminated on the upper surface of the division/multiplexing section 70 of the photoelectric conversion section 10 in FIG. 14 . The upper-stage demultiplexing/combining section 70 reflects the light rays in a predetermined wavelength band and performs demultiplexing/combining so as to extract the light rays in the predetermined wavelength band corresponding to the upper-stage photoelectric element. Light of other wavelengths is transmitted to the lower division/multiplexing section 70.
The lower splitting/combining unit 70 reflects the transmitted light from the upper splitting/combining unit 70 in a predetermined wavelength band and extracts the light ray in a predetermined wavelength band corresponding to the lower photoelectric element. Combine waves. Light of other wavelengths is transmitted to the lowermost stage demultiplexing/combining section 20.
The lowermost division/multiplexing section 20 is configured to split the transmitted light from the lower division/multiplexing section 70 into two photoelectric elements 21a, 21b as described above, thereby creating a four-circuit optical transmission module. 100 can be formed.
Similarly, by sequentially stacking further demultiplexing/combining sections 70 on the upper surface of the upper demultiplexing/multiplexing section 70, an optical transmission module 100 having five or more circuits can be formed.

<4. Third embodiment of optical transmission module according to the present disclosure>
Next, a third embodiment of the optical transmission module 100 according to the present disclosure will be described. In the third embodiment, as shown in FIG. 15, two light emitting elements 211 of the same wavelength band or two light receiving elements 212 of the same wavelength band are arranged as photoelectric elements 21a and 21b, and in actual use, Only one of them is used. That is, one of the two light emitting elements 211 or the light receiving elements 212 is used for "regular use" and the other is used for "spare", and both are not used at the same time.

In the third embodiment, for this purpose, the wavelength selection films 24a and 24b are not provided on the inclined surfaces 25a and 25b of the reflection and transmission parts 23a and 23b in the demultiplexing and multiplexing part 20, but only one of the wavelength selection films 24a and 24b is provided. The photoelectric elements 21a and 21b are configured to receive incident light, or to transmit or reflect light emitted from one of the photoelectric elements 21a and 21b.

Specifically, an example will be described in which the photoelectric elements 21a and 21b are both light receiving elements 212 and 212.
In FIG. 15, part of the incident light that passes through the first lens section 30 and travels along the optical axis LA2 passes through the inclined surface 25a, and the other part is reflected. That is, the light is divided into transmitted light and reflected light. The light transmitted through the inclined surface 25a continues along the optical axis LA2 and enters the light receiving element 212, which is the photoelectric element 21a.

On the other hand, the optical path of the reflected light on the inclined surface 25a is changed from the optical axis LA2 to the optical axis LA3. The reflected light then travels along the optical axis LA3 and enters the inclined surface 25b. The light incident on the inclined surface 25b is separated into transmitted light and reflected light.
The optical path of the reflected light on the inclined surface 25b is changed from the optical axis LA3 to the optical axis LA4. The reflected light then travels along the optical axis LA4 and enters the light receiving element 212, which is the photoelectric element 21b. In this way, when the photoelectric elements 21a and 21b are both light receiving elements 212 and 212, both light receiving elements 212 and 212 simultaneously receive light of all wavelengths passing through the optical fiber 90.

On the other hand, the light transmitted through the inclined surface 25b continues along the optical axis LA3, but is blocked by the light shielding film 28 formed at the boundary between the reflective and transmitting portion 23b and the adjacent second light guide 12. Therefore, no light leaks to other adjacent photoelectric elements 21a, 21b. Further, since the inclined surface 25b of the reflective/transmissive portion 23b only needs to totally reflect the light traveling along the optical axis LA3, there is no need to consider transmitted light. Therefore, a reflecting mirror may be formed on the inclined surface 25b instead of the wavelength selection film 24b.

In this way, since the wavelength selection films 24a and 24b are not provided on the inclined surfaces 25a and 25b, when both the photoelectric elements 21a and 21b are light receiving elements 212 and 212, they receive light of all wavelengths. Discrimination of the received optical signals may be performed using a signal processing circuit, signal processing software, or the like. Furthermore, when it is desired to perform demultiplexing of a predetermined wavelength band in the photoelectric conversion section 10, a wavelength selection film 24k is formed at the boundary between the first light guide 11 and the reflective/transmissive section 23a, as shown in FIG. , it may be configured to transmit only the light beams L1 and L2 in a predetermined wavelength band.

Next, a case where the photoelectric elements 21a and 21b are both light emitting elements 211 and 211 will be described. In this case, the optical paths of the respective light rays L1 and L2 emitted by the light emitting elements 211 and 211 are in the opposite direction to those in the case where the photoelectric elements 21a and 21b are both the light receiving elements 212 and 212, so a description thereof will be omitted.
Note that when both the photoelectric elements 21a and 21b are light emitting elements 211 and 211, it is only necessary for either one of the light emitting elements 211 and 211 to emit light when communication is required. It is not necessary to provide the selective films 24a and 24b to combine the respective light beams L1 and L2.

With the above configuration, in actual use, one of the photoelectric elements 21a and 21b is used regularly and the other is used as a spare. Alternatively, the photoelectric elements 21a and 21b may be used alternately for regular use and for backup. Furthermore, if either one of the photoelectric elements 21a, 21b is out of order, the failed photoelectric element 21a, 21b may be separated and operated. In other words, the communication system can be duplicated. Even if one of the photoelectric elements 21a, 21b breaks down, the optical receptacle unit 50 can be continuously operated until the next periodic inspection without removing it.
In addition, in the above, although the case of two photoelectric elements 21a and 21b was demonstrated, it is not limited to two and may be three or more. In this case, some of the photoelectric elements among the plurality of photoelectric elements may be used regularly, some of the other photoelectric elements may be used as spares, and furthermore, the regular use and the spares may be rotated. Specifically, for example, in the case of a configuration including three photoelectric elements 21a, 21b, and 21c (not shown), one photoelectric element 21a is used as a regular photoelectric element, and the remaining two photoelectric elements 21b, 21c is a spare photoelectric element.
Everything other than the above is the same as the third modified example of the first embodiment, so the explanation will be omitted.

<5. Fourth embodiment of optical transmission module according to the present disclosure>
[Configuration of fourth embodiment]
Next, a fourth embodiment of the optical transmission module 100 according to the present disclosure will be described. In this embodiment, as shown in FIG. 16, the second light guide 12 in the demultiplexing/combining section 20 is made of a low refractive index resin, and the third light guide 13 is made of a high refractive index resin. be.

That is, by forming the second light guide 12 with a low refractive index resin, the light ray L1 that passes through the reflection/transmission part 23a, passes through the wavelength selection film 24a, and enters the second light guide 12 is refracted, resulting in a short optical path length. It is configured so that the light is focused and incident on the photoelectric element 21a.

Furthermore, by forming the third light guide 13 with a high refractive index resin, the reflected light on the wavelength selection film 24a of the reflective/transmissive part 23a is refracted so that the optical path is widened when it enters the third light guide 13. , the light is condensed with a long optical path length and is incident on the photoelectric element 21b.
In this case, the refractive index and optical path length of each of the second light guide 12 and the third light guide 13 may be determined based on the external dimensions of the photoelectric conversion section 10, the photoelectric elements 21a, 21b, etc., and their arrangement.

Thereby, each of the photoelectric elements 21a and 21b can be arranged at the focal point of the first lens section 30 with a simple configuration.
The configuration other than the above is the same as that described in the basic form of the first embodiment, so the description will be omitted.

[Difference in refractive index and optical path in the fourth embodiment]
Next, an optical path when light is transmitted or reflected from the inclined surface 25a of the reflective/transmissive section 23a to the second light guide 12 having a different refractive index in the fourth embodiment will be described. When the reflective/transmissive portion 23a and the second light guide 12 have the same refractive index, the incident light travels straight along the optical axis LA2, so bending of the optical path does not pose a problem. However, if the refractive index of the second light guide 12 is made smaller than the refractive index of the reflective/transmissive part 23a, the refractive index of the two will be different and the incident light will be obliquely incident on the joint surface of the two. A problem arises in that the optical axis LA2 and the optical path are bent due to the refraction at the cemented surface.

Specifically, as shown in FIG. 17, if the refractive index of the reflective/transmissive portion 23a is n1, the refractive index of the second light guide 12 is n2, and the slope of the slope 25a is 45 degrees, then the slope Since the incident angle θ1 to 25a is θ1=45 degrees, the refraction angle θ2 of the transmitted light is as follows from Snell's law:
sin θ1/sin θ2=n2/n1 holds true.
Therefore, sin θ2=(n1/n2) sin θ1=(n1/n2)2 ^-1/2 . Therefore, θ2=sin ⁻¹ {(n1/n2)2 ^−1/2 }.
However, sin45°=2-1 ^/ 2.

Here, when the optical axis LA2 of the transmitted light on the inclined surface 25a is a straight line, in order for the transmitted light to travel straight along the optical axis LA2, the refraction angle θ2 must be 45 degrees. Therefore, in this case, it is necessary that (n1/n2)=1, that is, n2=n1.
However, as in this embodiment, when n1≠n2, the incident angle θ1 and the refraction angle θ2 are not the same angle (θ1≠θ2).
That is, the incident light when the refractive indexes of both are n1>n2 is refracted at the interface between the inclined surface 25a of the reflective-transmissive portion 23a and the second light guide 12. Then, as shown in FIG. 17, the optical path of the refracted light deviates from the straight optical path and travels while being bent at the second light guide 12.

Furthermore, when the refracted light passes through the second light guide 12 and exits into the air, it is refracted again at the interface with the air. Specifically, the incident angle from the second light guide 12 to the air is θ3, the refraction angle is θ4, the refractive index of the second light guide 12 is n2, the refractive index of the air is n0, and the refractive index of both is If the magnitude relationship of is n2>n0,
sin θ3/sin θ4=n0/n2 holds true.
Here, if the refractive index n0 of air is set to 1 (n0=1),
sin θ4=(n2/n0) sin θ3=n2 sin θ3.
That is, the value of the sine of the refraction angle θ4 of the optical path into the air is n2 times the value of the sine of the incident angle θ3 of the optical path into the second light guide 12. Therefore, as shown in FIG. 17, the optical axis LA2 of the incident light on the inclined surface 25a is bent by an angle θ3 at the interface between the reflective and transmitting portion 23a and the second light guide 12, and bends at the interface between air and air. As a result, the optical axis LA2 is bent by an angle θ4 compared to the original straight line.

Therefore, in the case where n2≠n1 is set in order to compensate for the difference in the optical path length of the optical axis LA3, the distance by which the optical axis LA2 of the transmitted light deviates from the straight optical path is calculated and the position of the photoelectric element 21a is determined. Just adjust it. Alternatively, adjustment may be made by setting the inclination of the inclined surface 25a to a value different from 45 degrees.

As described above, when the second light guide 12 is formed of a low refractive index resin, it is necessary to take into account that the optical axis LA2 is bent. Thereby, the light beam L1 that passes through the reflection-transmission part 23a and the wavelength selection film 24a and enters the second light guide 12 can be refracted and focused on the photoelectric element 21a with a short optical path length. Furthermore, the photoelectric element 21a can be disposed at the focal point of the first lens section 30.

Note that when the inclination of the inclined surface 25a is 45 degrees, the incident angle θ1 to the inclined surface 25a is 45 degrees (θ1=45°). Further, since the incident angle θ1 and the reflection angle are equal, the reflection angle is also θ1, which is also 45 degrees. Therefore, the incident light other than the light beam L1 to the wavelength selection film 24a is reflected in the direction of the optical axis LA3. In this embodiment, since the third light guide 13 is made of a high refractive index resin, its refractive index is different from the refractive index n1 of the reflective/transmissive portion 23a. However, since the optical axis LA3 is perpendicular to the third light guide 13, the optical axis LA3 is not bent due to refraction. That is, as shown in FIG. 17, the reflected light takes an optical path along the optical axis LA3 direction without being affected by the difference in the refractive indexes n1 and n2 and the refractive index of the third light guide 13. Can be done.

<6. Fifth embodiment of optical transmission module according to the present disclosure>
Next, a fifth embodiment of the optical transmission module 100 according to the present disclosure will be described. In this embodiment, as shown in FIG. 18, the photoelectric element 21a is disposed at the focal point of the first lens section 30, and the reflective/transmissive section 23b has a concave mirror-like inclined surface having a predetermined center of curvature and radius of curvature. A surface 25b and a wavelength selection film 24b are formed. The structure is such that the light incident on the concave mirror of the inclined surface 25b is reflected and focused, so that the light can be focused on the photoelectric element 21b.

Specifically, from the incident light that has been refracted by the first lens section 30 and has traveled along the optical axis LA2, the light ray L1 in a predetermined wavelength band is transmitted through the wavelength selection film 24a, and the light of other wavelengths is transmitted. reflected. The optical path of the reflected light is changed from the optical axis LA2 to the optical axis LA3, and travels along the optical axis LA3.

Here, the reflected light traveling along the optical axis LA3 is once condensed at the focal point of the first lens section 30 located on the optical axis LA3, and then spreads out to the wavelength selection film 24b of the concave mirror-like inclined surface 25b. incident on . The concave mirror-shaped wavelength selection film 24b reflects the light beam L2 in a predetermined wavelength band. The optical path of the reflected light beam L2 is changed from the optical axis LA3 to the optical axis LA4, and travels along the optical axis LA4 while condensing. Therefore, by arranging the photoelectric element 21b at a position where the light beam L2 is focused, the light beam L2 can be focused and received. As a result, the difference in the optical path length of the optical axis LA3 can be compensated for.

Furthermore, with this configuration, the second light guide 12 and the third light guide 13 can be made of a transparent material having the same refractive index as the reflective/ transmissive parts 23a and 23b. Furthermore, each of the photoelectric elements 21a and 21b can be arranged at the focal point of the first lens section 30 with a simple configuration.
The optical path when the photoelectric element 21b is the light emitting element 211 is simply the opposite of the optical path when receiving light, so the explanation will be omitted.
Further, the configuration other than the above is the same as that described in the basic form of the first embodiment, so the description will be omitted.

<7. Sixth embodiment of optical transmission module according to the present disclosure>
[Basic form of sixth embodiment]
Next, the basic form of the sixth embodiment of the optical transmission module 100 according to the present disclosure will be described. In the basic form of this embodiment, as shown in FIG. Concave mirror-like inclined surfaces 25a and 25b having a predetermined center of curvature and radius of curvature and wavelength selection films 24a and 24b are formed. The configuration is such that the light incident on the concave mirrors of both the inclined surfaces 25a and 25b and the wavelength selection films 24a and 24b is reflected and focused, so that the light can be focused on the photoelectric element 21b. This is what I did.

With this configuration, in the incident light that has been refracted by the first lens section 30 and has proceeded along the optical axis LA2, the light ray L1 in a predetermined wavelength band is transmitted through the light wavelength selection film 24a, and the other light rays are transmitted along the optical axis LA2. Light of wavelength is reflected. The optical path of the reflected wave is changed in direction from the optical axis LA2 to the optical axis LA3, and becomes parallel light along the optical axis LA3. Then, the light beam L2 in a predetermined wavelength band is reflected by the wavelength selection film 24b formed in the shape of a concave mirror on the inclined surface 25b, and is focused on the photoelectric element 21b. Thereby, the difference in optical path length between the photoelectric elements 21a and 21b can be compensated for, and the photoelectric element 21b can be arranged at the focal point position of the first lens section 30 to condense light.

Here, since the inclined surface 25a formed in the shape of a concave mirror forms a convex mirror when viewed from the first lens section 30 side, when light traveling along the optical axis LA2 enters the wavelength selection film 24a, Light other than the light beam L1 in the predetermined wavelength band that passes through the wavelength selection film 24a is reflected in the spreading direction. Therefore, by appropriately setting the center of curvature and the radius of curvature of the concave mirror, as shown in FIG. 19, it is possible to reflect the incident light that has traveled while condensing to form parallel light.
The optical path when the photoelectric element 21b is the light emitting element 211 is simply the opposite of the optical path when receiving light, so the explanation will be omitted.

Further, as shown in FIG. 19, by forming parallel light in the third light guide 13 via the wavelength selection film 24a, the optical path length is increased by the length of the optical axis LA3. The difference can be compensated for. Thereby, the distance between the reflection- transmission parts 23a and 23b can be set to an arbitrary length. In other words, they can be arranged at arbitrary intervals. Furthermore, the second light guide 12, the third light guide 13, and the reflective/ transmissive parts 23a and 23b can be formed of materials having the same refractive index. Therefore, there are fewer manufacturing restrictions when performing double-sided imprinting, etc., the process can be simplified, and equipment investment can be reduced.
The configuration other than the above is the same as that of the third modification of the first embodiment, so the explanation will be omitted.

[Modification of the sixth embodiment]
Next, a modification of the sixth embodiment of the optical transmission module 100 according to the present disclosure will be described. As shown in FIG. 20, a modification of this embodiment forms reflection- transmission parts 23a and 23b similar to those in FIG. It differs from the basic shape in that reflective/ transmissive parts 23c and 23d are provided, and the respective inclined surfaces 25c and 25d and wavelength selection films 24c and 24d are formed in a concave mirror shape.

That is, the incident light from the optical fiber 90 travels along the optical axis LA2, the reflected light on the inclined surface 25a and the wavelength selection film 24a becomes parallel light along the optical axis LA3, and then the concave mirror-like inclined surface 25b, 25c, 25d and the wavelength selection films 24b, 24c, 24d, each reflects light rays L2, L3, L4 in a predetermined wavelength band, and each of the photoelectric elements 21b, 21c, 21d receives the respective reflected light. It consists of Thereby, the difference in optical path length between the photoelectric elements 21a to 21d can be compensated for, and each of the photoelectric elements 21b, 21c, and 21d can be arranged at the focal point of the first lens section 30.
Incidentally, when the light traveling along the optical axis LA3 may be totally reflected, or when the photoelectric element 21d is the light emitting element 211, the inclined surface 25d of the reflective/transmissive part 23d has a wavelength selective film 24a, There is no need to consider transmitting light like 24b and 24c. Therefore, in such a case, a reflecting mirror may be formed on the inclined surface 25d instead of the wavelength selection film 24d.

Since the inclined surface 25a and the wavelength selection film 24a form a convex mirror when viewed from the first lens section 30 side, when light traveling along the optical axis LA2 enters the wavelength selection film 24a, it falls into a predetermined wavelength band. Light other than the light ray L1 is reflected in the spreading direction. Therefore, by appropriately setting the center of curvature and the radius of curvature of the wavelength selection film 24a, as shown in FIG. 20, it is possible to refract the incident light at the first lens portion and reflect the traveling incident light to form parallel light. Can be done.
In FIG. 20, a description has been given of the branching and multiplexing of light using four circuits, but by adding a similar configuration, it is possible to perform branching and multiplexing using more than four circuits.

Furthermore, if any of the photoelectric elements 21b, 21c, and 21d is the light emitting element 211, the optical path is simply the opposite of that for light reception, so the explanation will be omitted.
The configuration other than the above is the same as that of the basic form of the sixth embodiment and the third modification of the first embodiment, so a description thereof will be omitted.

<8. Seventh embodiment of optical transmission module according to the present disclosure>
Next, a seventh embodiment of the optical transmission module 100 according to the present disclosure will be described. As shown in the plan view of the photoelectric conversion unit 10 in FIG. 21 and the side view in FIG. The sets of 30 and 30 are arranged in two horizontal rows, the front row and the back row, with four pairs in the front row of the horizontal row (referring to the lower row in Figure 21), and four pairs in the rear row of the horizontal row (referring to the upper row in Figure 21). Four sets were arranged.

As shown in FIG. 22, the optical receptacle section 50 has two circuits of optical fibers 90 in each of the front and rear rows arranged in two stacks, one above the other. For this purpose, a large reflecting mirror 53 is formed in the optical receptacle section 50 so as to reflect the light from the optical path of the second lens section 60 in each of the front and rear rows.

That is, the optical receptacle section 50 includes a plurality of second lens sections 60, which are disposed facing each other on the optical axis LA2 of each of the plurality of first lens sections 30, which respectively transmit the demultiplexed and multiplexed light; It has a reflecting mirror 53 that reflects each transmitted light of the second lens part 60, and a plurality of connectors 52 that connect a plurality of optical fibers 90 corresponding to the plurality of reflected lights or incident lights on the reflecting mirror 53. and a receptacle substrate 51 configured to condense light onto an end surface 91 of an optical fiber 90 connected and fixed to each plug 52.
The configuration other than the above is the same as that of the basic form and the first modification of the first embodiment, so the explanation will be omitted.

<9. Effects of the demultiplexing and multiplexing section of the optical transmission module according to the present disclosure>
[Comparison with the third modification of the first embodiment]
Next, the effects of the demultiplexing/combining section 20 provided in the photoelectric conversion section 10 of the optical transmission module 100 according to the present disclosure will be explained. FIG. 23 is a plan view and a front view of the photoelectric conversion unit 10 of a comparative example for explaining the effect of the demultiplexing/combining unit 20 of the optical transmission module 100 according to the present disclosure. Further, FIG. 24 is a side view thereof. That is, FIGS. 23 and 24 are diagrams showing an example in which the photoelectric conversion section 10 is not provided with the demultiplexing/multiplexing section 20.

In the photoelectric conversion unit 10 of the comparative example, as shown in FIG. 23B, first lens units 30 and 30 are provided for each of the photoelectric elements 21a and 21b. In the plan view of FIG. 23A, four first lens sections 30 are arranged corresponding to the four photoelectric elements 21a and 21b. Since the photoelectric conversion section 10 of the comparative example does not include the demultiplexing/multiplexing section 20, the optical function corresponding to the demultiplexing/multiplexing section 20 is provided in the optical receptacle section 50.

FIG. 25 is a plan view and a front view of a portion of the photoelectric conversion unit 10 of the third modification of the first embodiment in which the photoelectric conversion unit 10 of the optical transmission module 100 according to the present disclosure is provided with the demultiplexing/multiplexing unit 20. . The front view shown in FIG. 25B corresponds to the third modification of the first embodiment shown in FIG. 5 with the optical receptacle part 50 removed. Further, a side view thereof is shown in FIG. 26.

As shown in the front view of FIG. 25B, the photoelectric conversion section 10 is provided with one first lens section 30 corresponding to the two photoelectric elements 21a and 21b. That is, in the plan view of FIG. 23A, four first lens sections 30 are arranged corresponding to each of the four photoelectric elements 21a and 21b. In contrast, in FIG. 25A, two first lens sections 30 are provided for four photoelectric elements 21a and 21b. Therefore, it can be seen that in the third modified example of the first embodiment shown in this figure, the number of required first lens sections 30 is only half that of the comparative example shown in FIGS. 23 and 24.

[Comparison with modification of the sixth embodiment]
FIG. 27 is a plan view and a front view of a portion of the photoelectric conversion unit 10 of a modification of the sixth embodiment in which the photoelectric conversion unit 10 of the optical transmission module 100 according to the present disclosure is provided with the demultiplexing/multiplexing unit 20. The front view shown in FIG. 27B corresponds to FIG. 20 of the modification of the sixth embodiment.

As shown in FIG. 27B, in the demultiplexing/combining section 20, one first lens section 30 is provided corresponding to the four photoelectric elements 21a, 21b, 21c, and 21d. That is, in the plan view of FIG. 27A, there are a total of four photoelectric elements 21a, 21b, 21c, and 21d, whereas one fourth of the first lens parts 30 is disposed. Therefore, it can be seen that in the modified example of the sixth embodiment, the required number of first lens sections 30 is one-fourth of that of the comparative example shown in FIG. 23.

[Summary of the effects of the demultiplexing and multiplexing section]
FIG. 28 is a comparative diagram summarizing the effects of the demultiplexing/combining section 20 described above. The upper column of the figure is a column of a plan view when the photoelectric conversion section 10 is provided with the demultiplexing/multiplexing section 20. The lower column of the figure is a column of a plan view when the photoelectric conversion section 10 is not provided with the demultiplexing/multiplexing section 20.
The column of two wavelengths in the upper column of this figure indicates that the photoelectric conversion section 10 corresponding to FIG. FIG. 6 is a plan view of a photoelectric conversion unit 10 of a third modified example (corresponding to FIG. 5).
In addition, the 4-wavelength column in the upper column indicates that the photoelectric conversion unit 10 corresponding to FIG. FIG. 22 is a plan view of the photoelectric conversion unit 10 of an example (corresponding to FIG. 20).

Each column in the lower column of FIG. 28 shows, in order from the left, the case of 1 wavelength (corresponding to FIG. 23A), the case of 2 wavelengths (an example in which 2 sets of FIG. 23A are arranged side by side), and the case of 4 wavelengths. 23A is a plan view of each photoelectric conversion unit 10 in the case (an example in which four sets of FIG. 23A are arranged in parallel). FIG. In the comparative example in the lower column, the demultiplexing and multiplexing is performed in the optical receptacle section 50, so the number of second lens sections 60 corresponding to the number of circuits is required. Furthermore, within the optical receptacle section 50, it is necessary to provide optical elements for demultiplexing and multiplexing corresponding to the number of circuits. For this reason, the structure of the optical receptacle section 50 becomes complicated, and moreover, the number of types thereof increases in order to accommodate various numbers of circuits. On the other hand, when the optical receptacle section 50 is not provided with a demultiplexing/multiplexing function (that is, when the photoelectric conversion section 10 is provided with the demultiplexing/multiplexing section 20), an increase in the number of second lens sections 60 can be suppressed. The number of optical fibers 90 can be reduced, and the number of man-hours for wiring the optical fibers 90 can be reduced.

As shown in FIG. 28, by providing the demultiplexing/combining section 20 in the photoelectric conversion section 10, the following effects can be achieved.
(1) Since the configuration is such that light is split and multiplexed in the splitting/combining unit 20 of the photoelectric conversion unit 10, the required number of first lens units 30 is significantly reduced relative to the number of photoelectric elements 21a, 21b, etc. can be reduced. Thereby, the optical transmission module 100 can be miniaturized or highly integrated.
(2) By stacking multiple layers of the demultiplexing/multiplexing section 20, it is possible to perform demultiplexing and multiplexing of three or more circuits. This allows the optical transmission module 100 to be made smaller or more highly integrated.
(3) Two light-emitting elements 211 or light-receiving elements 212 with the same wavelength band are arranged as the photoelectric elements 21a and 21b, and one of them is used as "regular use" and the other is used as "spare", and furthermore, the regular use and the reserve are used. It can be configured to be switchable. As a result, optical communication can be duplicated, and even if a failure occurs in either one of the photoelectric elements 21a, 21b, continuous operation can be performed without removing the optical receptacle part 50 until the next periodic inspection. can.
(4) By forming the third light guide 13 with a high refractive index resin and the second light guide 12 with a low refractive index resin, the difference in optical path length between the photoelectric elements 21a and 21b can be compensated for. , each can be arranged at the focal point of the first lens section 30. Thereby, light emission and light reception can be performed reliably.
(5) A concave mirror-shaped wavelength selection film 24b may be formed on the inclined surface 25b of the reflection/transmission section 23b in the demultiplexing/multiplexing section 20. As a result, the reflected light from the wavelength selection film 24a is once condensed at the focal point of the first lens section 30 on the optical axis LA3, and then is reflected by the concave mirror-shaped wavelength selection film 24b while spreading, and reaches the focal point of the concave mirror. The photoelectric element 21b is arranged at a position where the light is focused again. With this configuration, the second light guide 12 and the third light guide 13 can be made of a transparent material having the same refractive index as the reflective/ transmissive parts 23a and 23b. Further, with a simple configuration, the difference in optical path length between the photoelectric elements 21a and 21b can be compensated for, and each of the photoelectric elements 21a and 21b can be arranged at the focal point of the first lens section 30 to condense light.
(6) By arranging, for example, the inclined surfaces 25a to 25d of the reflection/transmission parts 23a to 23d and the wavelength selection films 24a to 24d in a concave mirror shape in the demultiplexing/multiplexing part 20, three or more circuits can be divided. Waves and wave combinations may be possible. Moreover, the difference in optical path length between the photoelectric elements 21a to 21d can be compensated for, and each of them can be arranged at the focal point of the first lens section 30 to condense light. As a result, the optical transmission module 100 can be made smaller or more highly integrated.
(7) A plurality of combinations of the photoelectric elements 21a, 21b of the plurality of circuits and the first lens section 30 are arranged, for example, in the front row and the rear row of the horizontal rows, and the optical receptacle section 50 is arranged, for example, in each of the front row and the rear row. By arranging the optical fibers 90 of the circuit in two layers, one above the other, the optical transmission module 100 can be miniaturized or highly integrated.
(8) The second lens section 60 of the optical receptacle section 50 and the first lens section 30 of the photoelectric conversion section 10 can be configured to couple with parallel light. Therefore, the mutual spacing may be arbitrary. Furthermore, there are no restrictions on positioning, making implementation easier. Moreover, coupling efficiency can be improved.
(9) Since the photoelectric elements 21a, 21b, etc. are joined to the demultiplexing/combining section 20 by soldering, positional deviation is less likely to occur due to the self-alignment effect, and it is easy to position and join them accurately and with high precision. can do.
(10) By providing the demultiplexing/multiplexing section 20 in the photoelectric conversion section 10, the optical receptacle section 50 does not need to provide the demultiplexing/multiplexing section 20 in accordance with the number of circuits, and the number of the second lens sections 60 can be reduced. can be reduced. Therefore, the structure of the optical receptacle section 50 can be simplified and standardized.
(11) As described above, it is possible to suppress an increase in the number of second lens sections 60 or reduce the number of second lens sections 60 to achieve high integration. Therefore, the number of optical fibers 90 can be reduced, and the number of man-hours for wiring the optical fibers 90 can be reduced.

Finally, the description of each embodiment described above is an example of the present disclosure, and the present disclosure is not limited to the embodiments described above. Therefore, it goes without saying that various changes can be made to the embodiments other than those described above, depending on the design, etc., as long as they do not depart from the technical idea of the present disclosure. Further, the effects described in this specification are merely examples and are not limited, and other effects may also exist.

Note that the present technology can also have the following configuration.
(1)
a first lens portion that refracts and focuses transmitted light between the optical fiber;
a second lens section disposed on the optical axis of the first lens section and facing the first lens section;
a receptacle board having a plug for connecting the optical fiber, which positions the end face of the optical fiber at the focal point of the second lens part;
a first light guide disposed on a surface of the first lens section that does not face the second lens section;
a demultiplexing/combining part disposed on a surface of the first light guide where the first lens part is not disposed, and demultiplexing or combining light transmitted through the first lens part;
A plurality of lights disposed in the demultiplexing/combining section and performing at least one of emitting light to the first lens section and receiving light from the first lens section via the demultiplexing/multiplexing section and the first light guide. photoelectric element,
An optical transmission module with
(2)
The demultiplexing/combining section is laminated into two layers, an upper stage and a lower stage, and the upper stage demultiplexing/multiplexing part reflects light in a predetermined wavelength band and transmits the light in a predetermined wavelength band to one of the photoelectric elements. The light of other wavelengths is transmitted from the upper division/multiplexing section to the lower division/multiplexing section. The optical transmission module according to (1) above, which is configured to separate and combine light in respective predetermined wavelength bands.
(3)
The demultiplexing/multiplexing section includes a first reflective/transmissive section having a first wavelength selection film formed on an inclined surface having a predetermined inclination angle on the optical axis of the first lens section;
a second reflective/transmissive part or a reflective mirror having a second wavelength selective film formed on an inclined surface having a predetermined inclination angle and arranged in parallel with the first reflective/transmissive part;
a third light guide arranged in parallel between the first reflective transmitting section and the second reflective transmitting section;
a second light guide arranged in parallel at a position opposite to the third light guide with the first reflective/transmissive part in between;
The optical transmission module according to (1) or (2) above.
(4)
The optical transmission module according to (3), wherein the first wavelength selection film is configured to transmit light in a predetermined wavelength band and reflect light in other wavelengths.
(5)
The optical transmission module according to (3) or (4), wherein the second wavelength selection film is configured to reflect light in a predetermined wavelength band and transmit light in other wavelengths.
(6)
The plurality of photoelectric elements disposed in the demultiplexing/combining section are capable of emitting or receiving light in the same wavelength band, and among the plurality of photoelectric elements, some of the photoelectric elements are used regularly and others are used. The optical transmission module according to (1) or (2), wherein the photoelectric element in the section is a spare, and further configured to be switchable between regular use and standby.
(7)
By forming the third light guide with a high refractive index resin and forming the second light guide with a low refractive index resin, each of the plurality of photoelectric elements is positioned at the focal point of the first lens portion. The optical transmission module according to any one of (1) to (6) above.
(8)
The first reflective transmitting section is formed in a plane mirror shape with respect to the incident light, and the second reflective transmitting section is formed in a concave mirror shape with respect to the reflected light from the first reflective transmitting section. The optical transmission module according to any one of (1) to (6), wherein each of the plurality of photoelectric elements is disposed at a focal point of the first lens section.
(9)
The first reflective transmitting section is formed in a convex mirror shape with respect to the incident light, and the second reflective transmitting section is formed in a concave mirror shape with respect to the reflected light from the first reflective transmitting section. The optical transmission module according to any one of (1) to (6), wherein each of the plurality of photoelectric elements is disposed at a focal point of the first lens section.
(10)
The optical transmission module according to any one of (1) to (9), wherein the demultiplexing/multiplexing section is provided with wiring connecting the photoelectric elements.
(11)
The optical transmission module according to (10), wherein the photoelectric element is soldered to the wiring.
(12)
The optical transmission module according to (10) or (11), wherein the wiring has a solder ball for connection to an external circuit.
(13)
Any of the transmitted light between the second lens part and the first lens part disposed on the optical axis opposite to the second lens part is configured to become parallel light. The optical transmission module according to any one of (1) to (12) above.
(14)
a plurality of second lens parts disposed opposite to each other on the optical axis of each of the plurality of first lens parts, each of which transmits the demultiplexed and multiplexed light;
a reflecting mirror that reflects the transmitted light of each of the plurality of second lens parts,
The receptacle board has a plurality of connectors that connect a plurality of optical fibers corresponding to a plurality of reflected lights or incident lights on the reflecting mirror, and the optical fibers connected and fixed to each of the connectors. The optical transmission module according to (1) above, configured to condense light onto the end face of the fiber.

10 Photoelectric conversion unit 11 First light guide 11A Glass substrate 12 Second light guide 13 Third light guide 14 Fourth light guide 20 Demultiplexing unit 21a, 21b, 21c, 21d Photoelectric element 211 Light emitting element 212 Light receiving Elements 23a, 23b First and second reflective/ transmissive sections 23c, 23d Reflective/transmissive sections 24a First wavelength selective film 24b Second wavelength selective film or reflective mirror 24c, 24k Wavelength selective film 24d Wavelength selective film or reflective mirror 25a, 25b Inclined Surface 28 Light shielding film 30 First lens part 40 Circuit board 41 Wiring 42 Solder ball 43 Solder ball 50 Optical receptacle part 51 Receptacle board 52 Junction 53 Reflector 60 Second lens part 70 Demultiplexing part 71 Second light guide 72 Third light guide 73a, 73b Reflective/ transmissive part 74a, 74b Wavelength selection film 75a, 75b Inclined surface 81 Resist 90 Optical fiber 91 End surface 100 Optical transmission module LA1 to LA6 Optical axis L1 to L4 Ray

Claims (14)

1. a first lens portion that refracts and focuses transmitted light between the optical fiber;
   a second lens section disposed on the optical axis of the first lens section and facing the first lens section;
   a receptacle board having a plug for connecting the optical fiber, which positions the end face of the optical fiber at the focal point of the second lens part;
   a first light guide disposed on a surface of the first lens section that does not face the second lens section;
   a demultiplexing/combining part disposed on a surface of the first light guide where the first lens part is not disposed, and demultiplexing or combining light transmitted through the first lens part;
   A plurality of lights disposed in the demultiplexing/combining section and performing at least one of emitting light to the first lens section and receiving light from the first lens section via the demultiplexing/multiplexing section and the first light guide. a photoelectric element,
   An optical transmission module with
2. The demultiplexing/combining section is laminated into two layers, an upper stage and a lower stage, and the upper stage demultiplexing/multiplexing part reflects light in a predetermined wavelength band and transmits the light in a predetermined wavelength band to one of the photoelectric elements. The light of other wavelengths is transmitted from the upper division/multiplexing section to the lower division/multiplexing section. 2. The optical transmission module according to claim 1, wherein the optical transmission module is configured to separate and combine light in respective predetermined wavelength bands.
3. The demultiplexing/multiplexing section includes a first reflective/transmissive section having a first wavelength selection film formed on an inclined surface having a predetermined inclination angle on the optical axis of the first lens section;
   a second reflective/transmissive part or a reflective mirror having a second wavelength selective film formed on an inclined surface having a predetermined inclination angle and arranged in parallel with the first reflective/transmissive part;
   a third light guide arranged in parallel between the first reflective transmitting section and the second reflective transmitting section;
   a second light guide arranged in parallel at a position opposite to the third light guide with the first reflective/transmissive part in between;
   The optical transmission module according to claim 1, comprising:
4. 4. The optical transmission module according to claim 3, wherein the first wavelength selective film is configured to transmit light in a predetermined wavelength band and reflect light in other wavelengths.
5. 4. The optical transmission module according to claim 3, wherein the second wavelength selective film is configured to reflect light in a predetermined wavelength band and transmit light in other wavelengths.
6. The plurality of photoelectric elements disposed in the demultiplexing/combining section are capable of emitting or receiving light in the same wavelength band, and among the plurality of photoelectric elements, some of the photoelectric elements are used regularly and others are used. 2. The optical transmission module according to claim 1, wherein said photoelectric element in said section is a spare, and further configured to be switchable between regular use and standby.
7. By forming the third light guide with a high refractive index resin and forming the second light guide with a low refractive index resin, each of the plurality of photoelectric elements is positioned at the focal point of the first lens portion. The optical transmission module according to claim 1, wherein the optical transmission module is provided with an optical transmission module according to claim 1.
8. The first reflective transmitting section is formed in a plane mirror shape with respect to the incident light, and the second reflective transmitting section is formed in a concave mirror shape with respect to the reflected light from the first reflective transmitting section. The optical transmission module according to claim 1, wherein each of the plurality of photoelectric elements is disposed at a focal point of the first lens section.
9. The first reflective transmitting section is formed in a convex mirror shape with respect to the incident light, and the second reflective transmitting section is formed in a concave mirror shape with respect to the reflected light from the first reflective transmitting section. The optical transmission module according to claim 1, wherein each of the plurality of photoelectric elements is disposed at a focal point of the first lens section.
10. The optical transmission module according to claim 1, wherein the demultiplexing/multiplexing section is formed with wiring connecting the photoelectric elements.
11. The optical transmission module according to claim 10, wherein the photoelectric element is soldered to the wiring.
12. The optical transmission module according to claim 10, wherein the wiring has a solder ball for connection to an external circuit.
13. Any of the transmitted light between the second lens part and the first lens part disposed on the optical axis opposite to the second lens part is configured to become parallel light. The optical transmission module according to claim 1.
14. a plurality of second lens parts disposed opposite to each other on the optical axis of each of the plurality of first lens parts, each of which transmits the demultiplexed and multiplexed light;
    a reflecting mirror that reflects the transmitted light of each of the plurality of second lens parts,
    The receptacle board has a plurality of sockets for connecting a plurality of optical fibers corresponding to a plurality of reflected lights or incident lights on the reflecting mirror, and the optical fibers connected and fixed to the respective sockets. The optical transmission module according to claim 1, wherein the optical transmission module is configured to condense light onto the end face of the fiber.

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