CN114624828B

CN114624828B - Optical module

Info

Publication number: CN114624828B
Application number: CN202011475053.0A
Authority: CN
Inventors: 张洪浩; 谢一帆; 傅钦豪; 李丹; 王腾飞; 刘凯
Original assignee: Hisense Broadband Multimedia Technology Co Ltd
Current assignee: Hisense Broadband Multimedia Technology Co Ltd
Priority date: 2020-12-14
Filing date: 2020-12-14
Publication date: 2023-04-14
Anticipated expiration: 2040-12-14
Also published as: CN114624828A

Abstract

The application discloses an optical module, which comprises a tube shell, a circuit board inserted into the tube shell, an optical receiving assembly, an optical fiber adapter and an optical transmitting assembly, wherein two opposite side surfaces of the tube shell are provided with openings to form a light receiving part and a light transmitting cavity which are arranged back to back respectively, and the light receiving part comprises a plurality of light through holes; the light receiving component is arranged in the light receiving part; the optical fiber adapter is arranged on one side of the tube shell, which is far away from the circuit board, and is communicated with the light emission cavity; the light emission component is arranged in the light emission cavity and is electrically connected with the circuit board, and the light emission component comprises a laser component, a lens array and a wavelength division multiplexing component which are sequentially arranged along a light emission light path, wherein the laser component is positioned below the light through holes and used for emitting a plurality of light beams with different wavelengths and conducting heat generated by the laser component to the surface of the tube shell by avoiding the light through holes. This application adopts a tube to arrange light emission subassembly and light receiving element, has solved and has adopted the not enough problem of discrete structure overall space, is favorable to the miniaturized development of optical module.

Description

Optical module

Technical Field

The application relates to the technical field of optical communication, in particular to an optical module.

Background

With the development of new services and application modes such as cloud computing, mobile internet, video and the like, the development and progress of the optical communication technology become increasingly important. In the optical communication technology, an optical module is a tool for realizing the interconversion of optical signals and is one of key devices in optical communication equipment, and the transmission rate of the optical module is continuously increased along with the development requirement of the optical communication technology.

Generally, to increase the transmission rate of an optical module, increasing the transmission channel in the optical module may be used, such as modifying the conventional optical module comprising one set of tosa (emitting light of one wavelength) and one set of rosa (receiving light of one wavelength) to comprise two sets of tosa (each set emitting light of one wavelength) and two sets of rosa (each set receiving light of one wavelength). Therefore, the occupied volumes of the optical transmitting sub-module and the optical receiving sub-module in the optical module are continuously increased, and further the further development of the optical module is not facilitated.

Disclosure of Invention

The application provides an optical module to it is great to solve the occupation volume of emission of light submodule and optical receiver submodule in the optical module, is unfavorable for the miniaturized problem of developing of optical module.

In order to solve the technical problem, the embodiment of the application discloses the following technical scheme:

the embodiment of the application discloses an optical module, includes:

a circuit board;

the light-emitting diode comprises a tube shell, a light-emitting cavity and a light-receiving cavity, wherein two opposite side surfaces of the tube shell are respectively provided with an opening, the light-receiving cavity and the light-emitting cavity are arranged back to back, and the light-receiving cavity comprises a plurality of light-transmitting holes; the circuit board is inserted into the tube shell;

a light receiving assembly disposed within the light receiving portion and electrically connected to the circuit board;

the optical fiber adapter is arranged on one side of the tube shell, which is far away from the circuit board, and is communicated with the light emission cavity;

the light emitting assembly is arranged in the light emitting cavity and is electrically connected with the circuit board; the laser assembly, the lens array and the wavelength division multiplexing assembly are sequentially arranged along a light emission light path, and the laser assembly is positioned below the light through hole and used for emitting a plurality of light beams with different wavelengths and conducting heat generated by the laser assembly to the surface of the tube shell by avoiding the light through hole; the lens array is used for converting the multiple beams of light beams into multiple collimated beams of light; the wavelength division multiplexing component is used for multiplexing a plurality of collimated light beams into a composite light beam and coupling the composite light beam to the optical fiber adapter.

The optical module comprises a circuit board, a tube shell, an optical receiving assembly, an optical fiber adapter and an optical transmitting assembly, wherein two opposite side surfaces of the tube shell are provided with openings respectively to form a light receiving part and a light transmitting cavity which are arranged back to back, and the light receiving part comprises a plurality of light through holes; the circuit board is inserted into the tube shell; the light receiving component is arranged in the light receiving part and is electrically connected with the circuit board; the optical fiber adapter is arranged on one side of the tube shell, which is far away from the circuit board, and is communicated with the light emission cavity; the light emitting component is arranged in the light emitting cavity and is electrically connected with the circuit board; the laser assembly is positioned below the light through holes and used for emitting a plurality of light beams with different wavelengths and conducting heat generated by the laser assembly to the surface of the tube shell by avoiding the light through holes; the lens array is used for converting the multiple collimated light beams into collimated light beams, and the wavelength division multiplexing assembly is used for multiplexing the multiple collimated light beams into a composite light beam and coupling the composite light beam to the optical fiber adapter. The application provides an optical module adopts a tube to come integrated light receiving component and optical transmission subassembly, and optical reception component and optical transmission subassembly adopt back-to-back setting, can solve the problem that the whole space of the optical module that adopts discrete optical transmission subassembly and optical reception subassembly is not enough, are favorable to the miniaturized development of optical module.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic diagram of connection relationship of an optical communication terminal;

fig. 2 is a schematic structural diagram of an optical network terminal;

fig. 3 is a schematic structural diagram of an optical module according to an embodiment of the present application;

fig. 4 is an exploded schematic view of an optical module according to an embodiment of the present disclosure;

fig. 5 is a schematic view illustrating an assembly of a circuit board and an optical sub-assembly in an optical module according to an embodiment of the present disclosure;

fig. 6 is an exploded schematic view of a circuit board and an optical sub-assembly in an optical module according to an embodiment of the present disclosure;

fig. 7 is a schematic partial structure diagram of an optical sub-module in an optical module according to an embodiment of the present disclosure;

fig. 8 is a schematic diagram of a DeMUX operation according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of a tube shell in an optical module according to an embodiment of the present disclosure;

fig. 10 is a schematic view of another angle structure of a tube shell in an optical module according to an embodiment of the present application;

fig. 11 is a partial cross-sectional view of a tube shell in an optical module according to an embodiment of the present disclosure;

fig. 12 is a schematic structural diagram of a light receiving module in an optical module according to an embodiment of the present disclosure;

fig. 13 is a schematic optical path diagram of a light receiving assembly in an optical module according to an embodiment of the present disclosure;

fig. 14 is a cross-sectional view of a light receiving module in an optical module according to an embodiment of the present disclosure;

fig. 15 is an assembly cross-sectional view of a light receiving module and a circuit board in an optical module according to an embodiment of the present disclosure;

fig. 16 is a schematic view illustrating assembly of a circuit board and an optical sub-assembly at another angle in an optical module according to an embodiment of the present disclosure;

fig. 17 is a schematic view illustrating a further angle assembly of a circuit board and an optical sub-assembly in an optical module according to an embodiment of the present disclosure;

fig. 18 is another exploded view of the circuit board and the optical sub-assembly in an optical module according to an embodiment of the present disclosure;

fig. 19 is a schematic view of another angle partial structure of an optical sub-assembly in an optical module according to an embodiment of the present application;

fig. 20 is a schematic structural diagram of a light emitting assembly in a light module according to an embodiment of the present disclosure;

fig. 21 is a schematic optical path diagram of a light emitting assembly in an optical module according to an embodiment of the present disclosure;

fig. 22 is another schematic angular structure diagram of a tube shell in an optical module according to an embodiment of the present disclosure;

fig. 23 is an assembly cross-sectional view of a light emitting module and a tube shell in an optical module according to an embodiment of the present disclosure.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

One of the core links of optical fiber communication is the interconversion of optical and electrical signals. The optical fiber communication uses optical signals carrying information to transmit in information transmission equipment such as optical fibers/optical waveguides and the like, and the information transmission with low cost and low loss can be realized by using the passive transmission characteristic of the light in the optical fibers/optical waveguides; meanwhile, the information processing device such as a computer uses an electric signal, and in order to establish information connection between the information transmission device such as an optical fiber or an optical waveguide and the information processing device such as a computer, it is necessary to perform interconversion between the electric signal and the optical signal.

The optical module realizes the function of interconversion of optical signals and electrical signals in the technical field of optical fiber communication, and the interconversion of the optical signals and the electrical signals is the core function of the optical module. The optical module is electrically connected with an external upper computer through a golden finger on an internal circuit board, and the main electrical connection comprises power supply, I2C signals, data information, grounding and the like; the electrical connection mode realized by the gold finger has become the mainstream connection mode of the optical module industry, and on the basis of the mainstream connection mode, the definition of the pin on the gold finger forms various industry protocols/specifications.

Fig. 1 is a schematic diagram of connection relationship of an optical communication terminal. As shown in fig. 1, the connection of the optical communication terminal mainly includes the interconnection among the optical network terminal 100, the optical module 200, the optical fiber 101, and the network cable 103.

One end of the optical fiber 101 is connected with a far-end server, one end of the network cable 103 is connected with local information processing equipment, and the connection between the local information processing equipment and the far-end server is completed by the connection between the optical fiber 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is made by the optical network terminal 100 having the optical module 200.

An optical port of the optical module 200 is externally connected to the optical fiber 101, and establishes bidirectional optical signal connection with the optical fiber 101; an electrical port of the optical module 200 is externally connected to the optical network terminal 100, and establishes bidirectional electrical signal connection with the optical network terminal 100; the optical module realizes the mutual conversion of optical signals and electric signals, thereby realizing the establishment of information connection between the optical fiber and the optical network terminal. Specifically, the optical signal from the optical fiber is converted into an electrical signal by the optical module and then input to the optical network terminal 100, and the electrical signal from the optical network terminal 100 is converted into an optical signal by the optical module and input to the optical fiber.

The optical network terminal is provided with an optical module interface 102, which is used for accessing an optical module 200 and establishing bidirectional electric signal connection with the optical module 200; the optical network terminal is provided with a network cable interface 104, which is used for accessing the network cable 103 and establishing bidirectional electric signal connection with the network cable 103; the optical module 200 is connected to the network cable 103 via the optical network terminal 100. Specifically, the optical network terminal transmits a signal from the optical module to the network cable and transmits the signal from the network cable to the optical module, and the optical network terminal serves as an upper computer of the optical module to monitor the operation of the optical module.

Thus, a bidirectional signal transmission channel is established between the remote server and the local information processing equipment through the optical fiber, the optical module, the optical network terminal and the network cable.

Common information processing apparatuses include routers, switches, electronic computers, and the like; the optical network terminal is an upper computer of the optical module, provides data signals for the optical module, and receives the data signals from the optical module, and the common upper computer of the optical module also comprises an optical line terminal and the like.

Fig. 2 is a schematic diagram of an optical network terminal structure. As shown in fig. 2, the optical network terminal 100 includes a circuit board 105, and a cage 106 is disposed on a surface of the circuit board 105; an electric connector is arranged in the cage 106 and used for connecting optical module electric ports such as golden fingers; the cage 106 is provided with a heat sink 107, and the heat sink 107 has a first boss portion such as a fin that increases a heat radiation area.

The optical module 200 is inserted into the onu 100, specifically, the electrical port of the optical module is inserted into the electrical connector inside the cage 106, and the optical port of the optical module is connected to the optical fiber 101.

The cage 106 is positioned on the circuit board, and the electrical connector on the circuit board is wrapped in the cage, so that the electrical connector is arranged in the cage; the optical module is inserted into the cage, the optical module is held by the cage, and heat generated by the optical module is conducted to the cage 106 and then diffused by the heat sink 107 on the cage.

Fig. 3 is a schematic diagram of an optical module structure provided in the embodiment of the present application, and fig. 4 is an exploded schematic diagram of an optical module provided in the embodiment of the present application. As shown in fig. 3 and 4, an optical module 200 provided in the embodiment of the present application includes an upper housing 201, a lower housing 202, an unlocking member 203, a circuit board 300, and an optical sub-module 400.

The upper shell 201 is covered on the lower shell 202 to form a wrapping cavity with two openings; the outer contour of the packaging cavity generally presents a square body. Specifically, the lower housing 202 includes a main board and two side boards located at two sides of the main board and arranged perpendicular to the main board; the upper shell comprises a cover plate, and the cover plate covers two side plates of the upper shell to form a wrapping cavity; the upper case may further include two side walls disposed at two sides of the cover plate and perpendicular to the cover plate, and the two side walls are combined with the two side plates to cover the upper case 201 on the lower case 202.

The two openings can be two end openings (204, 205) located at the same end of the optical module, or two openings located at different ends of the optical module; one opening is an electric port 204, and a gold finger of the circuit board extends out of the electric port 204 and is inserted into an upper computer such as an optical network terminal; the other opening is an optical port 205 for external optical fiber access to connect with the optical sub-module 400 inside the optical module; the optoelectronic devices such as the circuit board 300 and the optical sub-assembly 400 are located in the package cavity.

The assembly mode of combining the upper shell and the lower shell is adopted, so that the circuit board 300, the optical sub-module 400 and other devices can be conveniently installed in the tube shell, and the upper shell and the lower shell form the packaging protection tube shell at the outermost layer of the module; the upper shell and the lower shell are made of metal materials generally, electromagnetic shielding and heat dissipation are achieved, the tube shell of the optical module cannot be made into an integral component generally, and therefore when devices such as a circuit board are assembled, the positioning component, the heat dissipation component and the electromagnetic shielding component cannot be installed, and production automation is not facilitated.

The unlocking component 203 is located on the outer wall of the wrapping cavity/lower shell 202, and is used for realizing the fixed connection between the optical module and the upper computer or releasing the fixed connection between the optical module and the upper computer.

The unlocking component 203 is provided with a clamping component matched with the upper computer cage; the end of the unlocking member 203 is pulled to make the unlocking member 203 relatively move on the surface of the outer wall; the optical module is inserted into a cage of the upper computer, and the optical module is fixed in the cage of the upper computer by the clamping component of the unlocking component 203; by pulling the unlocking member 203, the engaging member of the unlocking member 203 moves along with the unlocking member, and further, the connection relationship between the engaging member and the upper computer is changed, so that the engagement relationship between the optical module and the upper computer is released, and the optical module can be drawn out from the cage of the upper computer.

The circuit board 300 is provided with circuit traces, electronic components (such as capacitors, resistors, triodes, and MOS transistors), and chips (such as an MCU, a laser driver chip, a limiting amplifier chip, a clock data recovery CDR, a power management chip, and a data processing chip DSP).

The circuit board 300 is used to provide signal circuits for signal electrical connections, which can provide signals. The circuit board 300 connects the electrical devices in the optical module together according to circuit design through circuit wiring to realize power supply, electrical signal transmission, grounding and other electrical functions.

The circuit board is generally a rigid circuit board, and the rigid circuit board can also realize a bearing effect due to relatively hard materials of the rigid circuit board, for example, the rigid circuit board can stably bear a chip; when the optical transceiver component is positioned on the circuit board, the rigid circuit board can also provide stable bearing; the hard circuit board can also be inserted into an electric connector in the upper computer cage, and specifically, a metal pin/gold finger is formed on the surface of the tail end of one side of the hard circuit board and is used for being connected with the electric connector; these are not easily implemented with flexible circuit boards.

A flexible circuit board is also used in a part of the optical module to supplement a rigid circuit board; the flexible circuit board is generally used in combination with a rigid circuit board, for example, the rigid circuit board may be connected to the optical transceiver module by using the flexible circuit board.

As shown in fig. 4, the optical module provided in the embodiment of the present application includes a tosa and a rosa, which are integrated into one optical subassembly, that is, the optical subassembly 400 integrates a light emitting element and a light receiving element therein. Alternatively, the light emitting element is closer to the lower case 202 than the light receiving element, but not limited thereto, and the light receiving element may be closer to the lower case 202 than the light emitting element.

Alternatively, the circuit board 300 may be directly inserted into the optical sub-assembly 400 and directly electrically connected to the light emitting and receiving components in the optical sub-assembly 400; the optical sub-assembly 400 may also be physically separated from the circuit board 300, and the circuit board may be connected through a flexible circuit board.

When the light emitting element is closer to the lower housing 202 than the light receiving element, the light emitting element and the light receiving element are integrated in the inner cavity of the optical subassembly 400, and the light emitting element and the light receiving element are separated by a partition, and the optical subassembly 400 is disposed in the package cavity formed by the upper housing 201 and the lower housing 202.

Fig. 5 is an assembly diagram of an optical sub-assembly 400 and a circuit board 300 in an optical module according to an embodiment of the present disclosure, and fig. 6 is an exploded diagram of the optical sub-assembly 400 and the circuit board 300 in the optical module according to the embodiment of the present disclosure. As shown in fig. 5 and 6, the optical subassembly 400 includes a package 410, a light emitting element disposed at a light emitting portion of the package 410, a light receiving element disposed at a light receiving portion of the package 410, the light receiving element and the light emitting element being stacked one on top of the other and separated by a partition in the package 410, the light receiving element being disposed above the partition, and the light emitting element being disposed below the partition. One end of the circuit board 300 is inserted into the package 410, and the light emitting module and the light receiving module are electrically connected to the circuit board, respectively, so that the light emitting module realizes electro-optical conversion, emits signal light, and the light receiving module receives the signal light, thereby realizing photoelectric conversion.

In the embodiment of the present application, the upper direction refers to the direction of the upper case 201 with respect to the circuit board 300, and the lower direction refers to the direction of the lower case 202 with respect to the circuit board 300. The cavity of the optical subassembly 400 is divided into a light receiving portion and a light emitting portion by a partition, a light receiving assembly is disposed in the light receiving portion, and a light emitting assembly is disposed in the lower light emitting portion; a plurality of optical fiber adapters are arranged on the left side of the optical sub-assembly 400, the optical transmission assembly is connected with one optical fiber adapter, and the optical fiber adapters are used for transmitting the signal light emitted by the optical transmission assembly to an external optical fiber to realize the emission of the signal light; the optical receiving assembly is connected with another optical fiber adapter, and the optical fiber adapter is used for transmitting the signal light transmitted by the external optical fiber into the optical receiving assembly to realize the receiving of the signal light.

Because the overall external dimension of the optical module conforms to the interface dimension of the upper computer and is limited by the industry standard, and the optical subassembly 400 has a large volume and cannot be arranged on the circuit board 300, one end of the circuit board 300 is inserted into the tube shell 410 to realize the electrical connection between the optical subassembly 400 and the circuit board 300; the circuit board 300 may be separated from the optical sub-assembly 400, and the electrical connection transfer may be implemented by a flexible circuit board.

A light receiving cavity and a light receiving cover plate are arranged on the upper part of the tube shell 410, and the light receiving cover plate covers the light receiving cavity from the upper part; the light receiving cavity is internally provided with devices related to light receiving, such as a lens, a light multiplexing component and the like. The optical fiber adapter is disposed on the left side of the case 410, one end of the light receiving cavity is connected to the optical fiber adapter, the optical fiber adapter receives signal light from the outside of the optical module, and the received signal light is transmitted to the light receiving chip via optical devices such as a lens disposed in the light receiving cavity. A notch is formed in one side of the package 410 facing the circuit board 300, the circuit board 300 is inserted into the package 410 through the notch, an end of the circuit board 300 inserted into the package 410 is provided with an optical receiving chip, a transimpedance amplifier and other electrical devices, a light beam transmitted through an optical lens such as a lens in the optical receiving cavity is emitted into the optical receiving chip on the circuit board 300, and photoelectric conversion is realized through the optical receiving chip.

In the optical module provided in the embodiment of the present application, the light receiving component in the optical sub-module 400 is configured to receive multiple signal lights with different wavelengths, the signal lights with different wavelengths are transmitted into the light receiving cavity through the optical fiber adapter, the splitting according to the wavelength is implemented by optical devices such as a wavelength division demultiplexing component (DeMUX) in the light receiving cavity, the signal lights split according to the wavelength are finally transmitted to the photosensitive surface of the corresponding light receiving chip, and the light receiving chip receives the signal lights through the photosensitive surface thereof. Generally, one light receiving chip is used for receiving signal light of one wavelength, and the light receiving module provided by the embodiment of the present application includes a plurality of light receiving chips. For example, when the light receiving module is used for receiving signal lights with 4 different wavelengths, the light receiving module includes 4 light receiving chips for correspondingly receiving the signal lights with 4 wavelengths; when the light receiving module is used for receiving the signal light with 8 different wavelengths, the light receiving module comprises 8 light receiving chips for correspondingly receiving the signal light with 8 wavelengths.

Fig. 7 is a schematic structural diagram of an optical subassembly 400 in an optical module according to an embodiment of the present disclosure. As shown in fig. 7, the optical sub-module 400 provided in the embodiment of the present application has 2 sets of light receiving elements integrated therein, the upper portion of the package 410 is provided with a first light receiving cavity 4101 and a second light receiving cavity 4102, the first light receiving cavity 4101 and the second light receiving cavity 4102 are arranged side by side, that is, the first light receiving cavity 4101 and the second light receiving cavity 4102 are arranged in front of and behind the width direction of the package 410, the first light receiving cavity 4101 is located at the front side of the package 410, and the second light receiving cavity 4102 is located at the rear side of the package 410. A first collimating lens and a first wavelength demultiplexing assembly 4201 are arranged in the first light receiving cavity 4101, a first optical fiber adapter 601 is arranged on the left side of the package 410, signal light transmitted by the first optical fiber adapter 601 is converted into a collimated light beam through the first collimating lens, the collimated light beam is transmitted into the first wavelength demultiplexing assembly 4201, and one collimated light beam is divided into a plurality of signal lights with different wavelengths by the first wavelength demultiplexing assembly 4201; a second collimating lens and a second wavelength demultiplexing assembly 4202 are disposed in the second light receiving cavity 4102, a second fiber adapter 602 is disposed on the left side of the package 410, signal light transmitted by the second fiber adapter 602 is converted into a collimated light beam by the second collimating lens, the collimated light beam is transmitted to the second wavelength demultiplexing assembly 4202, and the collimated light beam is divided into a plurality of signal lights with different wavelengths by the second wavelength demultiplexing assembly 4202.

Fig. 8 is an operational schematic diagram of a DeMUX for splitting a beam including 4 wavelengths (β 1, β 2, β 3, and β 4) according to an embodiment of the present application. The wavelength division demultiplexing component comprises an optical inlet for inputting signal light with various wavelengths on the left side, and a plurality of optical outlets for emitting light on the right side, wherein each optical outlet is used for emitting signal light with one wavelength. As shown in fig. 8, the signal light enters the DeMUX through the incident light port of the DeMUX, and the β 1 signal light reaches the light exit port of the DeMUX after six different reflections at six different positions of the DeMUX; the beta 2 signal light is reflected for four times to reach the light outlet of the DeMUX at four different positions; the beta 3 signal light is reflected twice differently through two different positions of the DeMUX to reach the light outlet; the beta 4 signal light is directly transmitted to the light outlet after being incident to the DeMUX. Therefore, signal light with different wavelengths enters the DeMUX through the same light inlet and is output through different light outlets, and beam splitting of the signal light with different wavelengths is achieved. In the embodiment of the present application, the DeMUX is not limited to use with beam splitting including 4 wavelength beams, and can be selected according to actual needs.

Fig. 9 is a schematic structural diagram of a tube shell 410 in an optical module provided in an embodiment of the present application, and fig. 10 is another schematic structural diagram of an angle of the tube shell 410 in the optical module provided in the embodiment of the present application. As shown in fig. 9 and 10, a first through hole 4112 and a second through hole 4113 are formed in the left sidewall of the package 410, the first fiber optic adapter 601 communicates with the first light receiving cavity 4101 through the first through hole 4112, and the first collimating lens is disposed between the first through hole 4112 and the first wavelength division demultiplexing assembly 4201; the second fiber optic adapter 602 communicates with the second light receiving cavity 4102 through the second through hole 4113, and the second collimating lens is disposed between the second through hole 4113 and the second wavelength division demultiplexing assembly 4202.

The first light receiving cavity 4101 includes a bottom plate and side plates surrounding the bottom plate, the bottom plate and the side plates surrounding to form a cavity structure for accommodating the first collimating lens and the first wavelength division demultiplexing assembly 4201. A first cover plate fixing glue groove 4101a is formed in the top of the side plate of the first light receiving cavity 4101, and the first light receiving cover plate 401 may be fixedly connected to the first light receiving cavity 4101 by glue. Optionally, the first cover plate fixing glue groove 4101a forms a closed loop structure at the top of the side plate of the first light receiving cavity 4101, so that the glue area of the first light receiving cover plate 401 at the top of the side plate of the first light receiving cavity 4101 can be increased, and the packaging reliability of the top of the side plate of the first light receiving cover plate 401 and the top of the first light receiving cavity 4101 can be fully ensured. Further, a first rework opening 4101b is further provided at the top of the side plate of the first light receiving cavity 4101, the first rework opening 4101b is provided at the edge of the top of the side plate of the first light receiving cavity 4101, and the first rework opening 4101b is communicated with the first cover plate fixing glue groove 4101a. When the devices inside the first light receiving cavity 4101 need to be repaired after the first light receiving cover plate 401 and the first light receiving cavity 4101 are packaged, the first light receiving cover plate 401 can be detached from the first light receiving cavity 4101 through the first repairing opening 4101b, so that the first light receiving cover plate 401 can be detached without damaging the first light receiving cover plate 401 or the first light receiving cavity 4101, and the repairing difficulty and cost are reduced.

Similarly, the second light receiving cavity 4102 includes a bottom plate and side plates surrounding the bottom plate, the bottom plate and the side plates surrounding to form a cavity structure for accommodating the second collimating lens and the second wavelength division demultiplexing assembly 4202. A second cover fixing glue groove 4102a is provided at the top of the side plate of the second light receiving cavity 4102, and the second light receiving cover 402 can be fixedly connected to the second light receiving cavity 4102 by glue. Optionally, the second cover plate fixing glue groove 4102a forms a closed loop structure at the top of the side plate of the second light receiving cavity 4102, so that the glue area of the second light receiving cover plate 402 at the top of the side plate of the second light receiving cavity 4102 can be increased, and the package reliability at the top of the side plates of the second light receiving cover plate 402 and the second light receiving cavity 4102 can be fully ensured. Further, a second rework opening 4102b is further provided at the top of the side plate of the second light receiving cavity 4102, the second rework opening 4102b is provided at the edge of the top of the side plate of the second light receiving cavity 4102, and the second rework opening 4102b communicates with the second cover plate fixing glue groove 4102a. When the devices inside the second light receiving cavity 4102 need to be repaired after the second light receiving cover plate 402 and the second light receiving cavity 4102 are encapsulated, the second light receiving cover plate 402 can be detached from the second light receiving cavity 4102 through the second repair opening 4102b, so that the second light receiving cover plate 402 can be detached without damaging the second light receiving cover plate 402 or the second light receiving cavity 4102, and the repair difficulty and cost can be reduced.

In some embodiments, a bottom plate of the first light receiving cavity 4101 is provided with a first DeMUX fixing glue slot 4108, and the first DeMUX fixing glue slot 4108 is used for placing glue. For example, when it is necessary to fix the first wavelength demultiplexing assembly 4201, glue is dispensed in the first DeMUX fixing glue tank 4108, and then the first wavelength demultiplexing assembly 4201 is mounted and placed on the first DeMUX fixing glue tank 4108, and the glue is solidified to complete the fixing of the first wavelength demultiplexing assembly 4201 on the base plate. Similarly, a second DeMUX fixing glue groove 4110 is disposed on the bottom plate of the second light receiving cavity 4102, and the second DeMUX fixing glue groove 4110 is used for holding glue. For example, when it is required to fix the second wavelength division demultiplexing component 4202, glue is dispensed in the second DeMUX fixing glue groove 4110, and then the second wavelength division demultiplexing component 4202 is mounted and placed on the second DeMUX fixing glue groove 4110, and the glue is solidified to complete the fixing of the second wavelength division demultiplexing component 4202 on the substrate.

In the embodiment of the present application, a first slot 4103 and a second slot 4104 are disposed on one side of the case 410 facing the circuit board 300, the first slot 4103 and the second slot 4104 are disposed back and forth along the width direction of the case 410, wherein the first slot 4103 and the second slot 4104 are both opened on the upper side and the right side, the first slot 4103 is separated from the second slot 4104 by a separation plate 4111, a first light receiving component 430 is disposed in the first slot 4103, and a second light receiving component 440 is disposed in the second slot 4104. Taking the example of receiving 8 wavelengths of light including two wavelength bands, a single wavelength band includes 4 wavelengths of light, where signal light transmitted by the first optical fiber adapter 601 is converted into a collimated light beam through the first collimating lens, the collimated light beam is demultiplexed into 4 light beams with different wavelengths through the first wavelength demultiplexing assembly 4201, the 4 light beams with different wavelengths are respectively transmitted to the first light receiving assembly 430, and photoelectric conversion is implemented by the first light receiving assembly 430; the signal light transmitted by the second fiber adapter 602 is converted into a collimated light beam by the second collimating lens, the collimated light beam is demultiplexed into 4 light beams with different wavelengths by the second wavelength division demultiplexing component 4202, the 4 light beams with different wavelengths are transmitted to the second light receiving component 440, and the second light receiving component 440 performs photoelectric conversion.

Fig. 11 is a partial cross-sectional view of a package 410 in an optical module according to an embodiment of the present disclosure. As shown in fig. 11, the first light receiving cavity 4101 and the first slot 4103 can be communicated through light passing holes 4109, that is, a plurality of light passing holes 4109 are provided between the right side wall of the first light receiving cavity 4101 and the left side wall of the first slot 4103, and a plurality of light beams with different wavelengths demultiplexed by the first wavelength demultiplexing component 4201 in the first light receiving cavity 4101 are transmitted to the first light receiving component 430 through the corresponding light passing holes 4109. Similarly, the second light receiving cavity 4102 and the second slot 4104 can be communicated through light transmitting holes, that is, a plurality of light transmitting holes 4109 are provided between the right side wall of the second light receiving cavity 4102 and the left side wall of the second slot 4104, and a plurality of light beams with different wavelengths demultiplexed by the second wavelength demultiplexing component 4202 in the second light receiving cavity 4102 are transmitted to the second light receiving component 440 through the corresponding light transmitting holes 4109.

In this embodiment, the first wavelength division demultiplexing component 4201 is configured to demultiplex one light beam into 4 light beams with different wavelengths, and therefore, 4 light passing holes 4109 are disposed between the first light receiving cavity 4101 and the first slot 4103, the 4 light passing holes 4109 are sequentially disposed in front of and behind the width direction of the package 410, and the 4 output light ports of the first wavelength division demultiplexing component 4201 and the 4 light passing holes 4109 are disposed in a one-to-one correspondence manner, so that the 4 light beams with different wavelengths output by demultiplexing by the first wavelength division demultiplexing component 4201 are respectively transmitted to the first light receiving component 430 through the corresponding light passing holes 4109. Similarly, the second wavelength division demultiplexing component 4202 is configured to demultiplex one light beam into 4 light beams with different wavelengths, so that 4 light passing holes 4109 are disposed between the second light receiving cavity 4102 and the second slot 4104, the 4 light passing holes 4109 are sequentially disposed in front of and behind the package 410 in the width direction, and the 4 output light ports of the second wavelength division demultiplexing component 4202 are disposed in one-to-one correspondence with the 4 light passing holes 4109, so that the second wavelength division demultiplexing component 4202 demultiplexes the 4 light beams with different wavelengths output to be transmitted to the second light receiving component 440 through the corresponding light passing holes 4109.

In this embodiment, the first light receiving cavity 4101 and the first slot 4103 may also be directly connected to form an integrated cavity, a first collimating lens and a first wavelength division demultiplexing component 4201 are disposed on one side of the integrated cavity close to the first optical fiber adapter 601, and a first light receiving component 430 is disposed on one side of the integrated cavity close to the circuit board 300, so that the signal light transmitted by the first optical fiber adapter 601 is converted into a collimated light beam by the first collimating lens, the collimated light beam is demultiplexed into 4 light beams with different wavelengths by the first wavelength division demultiplexing component 4201, and the 4 light beams with different wavelengths are directly transmitted to the first light receiving component 430. Similarly, the second light receiving cavity 4102 and the second slot 4104 may also be directly communicated with an integrated cavity, a second collimating lens and a second wavelength division demultiplexing component 4202 are disposed on a side of the integrated cavity close to the second optical fiber adapter 602, and a second light receiving component 440 is disposed on a side of the integrated cavity close to the circuit board 300, so that the signal light transmitted by the second optical fiber adapter 602 is converted into a collimated light beam by the second collimating lens, the collimated light beam is demultiplexed into 4 light beams with different wavelengths by the second wavelength division demultiplexing component 4202, and the 4 light beams with different wavelengths are directly transmitted to the second light receiving component 440.

Compared with the mode that the first light receiving cavity 4101 and the first slot 4103 are communicated into an integral cavity, the mode that the first light receiving cavity 4101 and the first slot 4103 are communicated through the light through hole 4109 can process the tube shell 410 less, and keep more structures of the tube shell 410, so that heat generated by the optoelectronic devices of the light receiving component and the light emitting component is conducted to the upper shell 201 and the lower shell 202 through the place without the drilled hole on the tube shell 410, and the heat dissipation efficiency of the optical sub-module 400 can be increased.

Fig. 12 is a schematic structural diagram of a light receiving element in an optical subassembly 400 in an optical module according to an embodiment of the present disclosure, and fig. 13 is a schematic optical path diagram of the light receiving element in the optical subassembly 400 in the optical module according to the embodiment of the present disclosure. As shown in fig. 12 and 13, each of the first light receiving element 430 and the second light receiving element 440 includes a plurality of light receiving chips, and each of the light receiving chips is a PD (photodetector), such as an APD (avalanche photo diode), and is configured to convert the received signal light into a photocurrent. Optionally, the light receiving chips in the first light receiving assembly 430 and the second light receiving assembly 440 are respectively disposed on the surface of a metallized ceramic, the surface of the metallized ceramic forms a circuit pattern, which can supply power to the light receiving chips, and then the metallized ceramic provided with the light receiving chips is mounted on the circuit board 300, or the light receiving chips are mounted on a flexible circuit board, which is electrically connected to the circuit board 300.

In this embodiment, the first light receiving element 430 and the second light receiving element 440 further include a transimpedance amplifier respectively, and the transimpedance amplifier is directly mounted on the circuit board 300 and connected to the corresponding light receiving chip, and receives the current signal generated by the light receiving chip and converts the received current signal into a voltage signal. Alternatively, the transimpedance amplifier is connected to the corresponding light receiving chip by Wire Bonding, such as by Gold Wire Bonding.

Specifically, the first light receiving element 430 includes a first ceramic substrate 4304 and a first transimpedance amplifier 4305, and the first transimpedance amplifier 4305 is disposed on one side of the first ceramic substrate 4304, that is, the first transimpedance amplifier 4305 is located on the right side of the first ceramic substrate 4304. The first ceramic substrate 4304 is provided with 4 first optical receiving chips 4303, and the first ceramic substrate 4304 is connected to the first transimpedance amplifier 4305 by wire bonding, so as to connect the first optical receiving chip 4303 and the first transimpedance amplifier 4305. When the routing length is larger, the inductance generated by routing is larger, the signal mismatching is larger, the signal output by the first light receiving chip 4303 is a small signal, and the signal quality is reduced, so that the first light receiving chip 4303 and the first transimpedance amplifier 4305 are close to each other as much as possible, the routing length is reduced, the signal transmission quality is ensured, the first transimpedance amplifier 4305 is arranged on one side of the first ceramic substrate 4304, and the first ceramic substrate 4304 is close to the first transimpedance amplifier 4305 as much as possible.

In the embodiment of the present application, the first ceramic substrate 4304 is further configured to elevate the first light receiving chip 4303 so that the electrodes of the first light receiving chip 4303 and the pins on the first transimpedance amplifier 4305 are on the same plane, thereby ensuring that the wire bonding between the first light receiving chip 4303 and the first transimpedance amplifier 4305 is the shortest.

Similarly, the second light receiving element 440 includes a second ceramic substrate 4404 and a second transimpedance amplifier 4405, and the second transimpedance amplifier 4405 is disposed on one side of the second ceramic substrate 4404, i.e., the second transimpedance amplifier 4405 is disposed on the right side of the second ceramic substrate 4404. Wherein, the second ceramic substrate 4404 is provided with 4 second light receiving chips 4403, and the second ceramic substrate 4404 is connected to the second transimpedance amplifier 4405 by wire bonding, so as to realize the connection between the second light receiving chip 4403 and the second transimpedance amplifier 4405. When the length of the wire bonding is larger, the inductance generated by the wire bonding is larger, the signal mismatching is larger, the signal output by the second light receiving chip 4403 is a small signal, and the signal quality is reduced, so that the second light receiving chip 4403 and the second transimpedance amplifier 4405 are as close as possible, the length of the wire bonding is reduced, the signal transmission quality is ensured, the second transimpedance amplifier 4405 is arranged on one side of the second ceramic substrate 4404, and the second ceramic substrate 4404 is close to the second transimpedance amplifier 4405 as far as possible.

In this embodiment, the second ceramic substrate 4404 is further configured to pad up the second light receiving chip 4403, so that the electrodes of the second light receiving chip 4403 and the pins on the second transimpedance amplifier 4405 are on the same plane, and the shortest wire bonding between the second light receiving chip 4403 and the second transimpedance amplifier 4405 is ensured.

In this embodiment, if the pins of the transimpedance amplifier are enough, one transimpedance amplifier chip may be used for the first transimpedance amplifier 4305 and the second transimpedance amplifier 4405, and then 4 first optical receiving chips 4303 and 4 second optical receiving chips 4403 may be disposed on one ceramic substrate.

In order to facilitate the optical receiving chip to receive the signal light, the first optical receiving assembly 430 further includes a first lens array 4301, where the first lens array 4301 is used to adjust optical paths of the 4 optical beams with different wavelengths output by the first wavelength division demultiplexing assembly 4201 in the process of transmitting the optical beams to the first optical receiving assembly 430; the second light receiving module 440 further includes a second lens array 4401, and the second lens array 4401 is used for adjusting optical paths of the 4 optical beams with different wavelengths output by the second wavelength division demultiplexing module 4202 during transmission to the second light receiving module 440.

In this embodiment, an optical axis of the first lens array 4301 is parallel to the bottom surface of the first slot 4103, and simultaneously, a photosensitive surface of the first light receiving chip 4303 is also parallel to the bottom surface of the first slot 4103, but the first light receiving chip 4303 is disposed on the upper surface of the circuit board 300, and there is a height difference between the bottom surface of the first slot 4103 and the upper surface of the circuit board 300, so to ensure that the first light receiving chip 4303 receives signal light normally, the first light receiving assembly 430 further includes a first reflection prism 4302, the first reflection prism 4302 is disposed above the first ceramic substrate 4304, and covers 4 first light receiving chips 4303 disposed on the first ceramic substrate 4304, and an optical axis direction of the signal light emitted from the first lens array 4301 is changed by the reflection surface of the first reflection prism 4302, so that the optical axis of the signal light emitted from the first lens array 4301 is converted from being parallel to the bottom surface of the first slot 4103 to be perpendicular to the first bottom surface 4103, thereby enabling the signal light to be incident perpendicularly to the photosensitive surface of the corresponding to the photosensitive chip 4303.

The signal light transmitted into the first light receiving cavity 4101 through the first optical fiber adapter 601 is converted into collimated light beams through the first collimating lens, the collimated light beams are incident into the first wavelength division demultiplexing assembly 4201, one collimated light beam is demultiplexed into 4 light beams with different wavelengths through the first wavelength division demultiplexing assembly 4201, the 4 light beams with different wavelengths are transmitted to the corresponding lenses of the first lens array 4301 in the first slot 4103 through the corresponding light passing holes 4109 respectively and are transmitted to the first reflecting prism 4302 after being focused by the corresponding lenses, when the 4 light beams with different wavelengths are transmitted to the reflecting surface of the first reflecting prism 4302 and are reflected by the reflecting surface of the first reflecting prism 4302, so that the transmission direction of the light beams is changed from the direction parallel to the bottom surface of the first slot 4103 to the direction perpendicular to the bottom surface of the first slot 4103, the 4 light beams after being changed in anti-line are transmitted to the corresponding first light receiving chip 4303 on the first ceramic substrate 4304 below the reflecting surface of the first reflecting prism 4302 respectively, and the signal light receiving chip 4303 is converted into photoelectric signals through the first photoelectric receiving chip 4303.

Similarly, the optical axis of the second lens array 4401 is parallel to the bottom surface of the second slot 4104, and the photosensitive surface of the second light receiving chip 4403 is also parallel to the bottom surface of the second slot 4104, but the second light receiving chip 4403 is disposed on the upper surface of the circuit board 300, and there is a height difference between the bottom surface of the second slot 4104 and the upper surface of the circuit board 300, so in order to ensure that the second light receiving chip 4403 receives the signal light normally, the second light receiving assembly 440 preferably includes a second reflecting prism 4402, the second reflecting prism 4402 is disposed above the second ceramic substrate 4404, and covers the 4 second light receiving chips 4403 disposed on the second ceramic substrate 4404, and the direction of the optical axis of the signal light emitted from the second lens array 4401 is changed by the reflecting surface of the second reflecting prism 4402, so that the optical axis of the signal light emitted from the second lens array 4401 is changed from being parallel to the bottom surface of the second slot 4104 to be perpendicular to the photosensitive surface of the second slot 4104, and the signal light is perpendicularly incident on the photosensitive chip 4403.

Fig. 14 is a cross-sectional view of a second light receiving element 440 in an optical module provided in an embodiment of the present application in a package 410, and fig. 15 is an assembly cross-sectional view of the second light receiving element 440, the package 410 and a circuit board 300 in an optical module provided in an embodiment of the present application. As shown in fig. 14 and 15, the signal light transmitted into the second light receiving cavity 4102 through the second optical fiber adapter 602 is converted into a collimated light beam through the first collimating lens, the collimated light beam enters the second wavelength demultiplexing assembly 4202, one collimated light beam is demultiplexed into 4 light beams with different wavelengths through the second wavelength demultiplexing assembly 4202, the 4 light beams with different wavelengths are transmitted to the corresponding lenses of the second lens array 4401 in the second slot 4104 through the corresponding light passing holes 4109, and are transmitted to the second reflecting prism 4402 through the corresponding lenses after being focused, when the 4 light beams with different wavelengths are transmitted to the reflecting surface of the second reflecting prism 4402, the light beams are reflected by the reflecting surface of the second reflecting prism 4402, so that the transmission direction of the light beams is changed from the direction parallel to the bottom surface of the second slot 4104 to the direction perpendicular to the bottom surface of the second slot 4104, the changed direction of the 4 light beams are transmitted to the corresponding second ceramic substrate 4403 on the second ceramic substrate 4404 below the reflecting surface of the second reflecting prism 4402, and the second light receiving chip 4403 is implemented by the second optical receiving chip.

In this embodiment, the first reflection prism 4302 and the second reflection prism 4402 are both 45 ° reflection prisms, that is, the first reflection prism 4302 and the second reflection prism 4402 respectively include a 45 ° reflection surface, the 45 ° reflection surface of the first reflection prism 4302 covers 4 first light receiving chips 4303 disposed on the first ceramic substrate 4304, and the 45 ° reflection surface of the second reflection prism 4402 covers 4 second light receiving chips 4403 disposed on the second ceramic substrate 4404.

Since the first slot 4103 and the second slot 4104 are slots with open upper portions, in order to protect the first lens array 4301 and the first reflection prism 4302 in the first slot 4103 and the second lens array 4401 and the second reflection prism 4402 in the second slot 4104, the cover 500 is provided above the first slot 4103 and the second slot 4104, the cover 500 is a tube housing with both left and lower sides open, the first lens array 4301 and the first reflection prism 4302 are mounted to the first slot 4103 according to the light path of the first light receiving component 430, and the second lens array 4401 and the second reflection prism 4402 are mounted to the second slot 4104 according to the light path of the second light receiving component 440, the cover 500 is downwardly covered with the first slot 4103 and the second slot 4104, the lower side opening of the cover 500 is in contact with the upper surface of the circuit board 300, the upper surface, the front side surface, and the rear side surface of the cover 500 are respectively located on the same plane with the upper surface, the front side surface, the rear side surface of the tube housing 410, so that the first slot 4103 and the second slot 4104 are located in the cavity, so that the second slot 4104 and the light receiving component 500 are disposed in the cavity, thereby forming the second slot 4104.

A first notch 4114 is disposed on one side of the package 410 close to the circuit board 300, the first notch 4114 is located below the first slot 4103 and the second slot 4104, and the bottom surface of the first notch 4114 is parallel to the bottom surfaces of the first slot 4103 and the second slot 4104, so that when one end of the circuit board 300 is inserted into the first notch 4114, the surface of the circuit board 300 is parallel to the bottom surfaces of the first slot 4103 and the second slot 4104, and the first ceramic substrate 4304, the first transimpedance amplifier 4305, the second ceramic substrate 4404, and the second transimpedance amplifier 4405 mounted on the circuit board 300 are also parallel to the bottom surfaces of the first slot 4103 and the second slot 4104, so that the first reflective prism 4302 reflects the light beam focused by the first lens array 4301 to the corresponding first light receiving chip 4303 on the first ceramic substrate 4304, and the second reflective prism 4402 reflects the light beam focused by the second lens array 4401 to the corresponding second light receiving chip 4403 on the second ceramic substrate 4304.

A second gap is arranged between the first gap 4114 and the bottom surfaces of the first slot 4103 and the second slot 4104, the lower side of the second gap is communicated with the first gap 4114, and the right side of the second gap is provided with an opening; an aluminum nitride ceramic substrate 800 is disposed in the second notch, one side of the aluminum nitride ceramic substrate 800 contacts with the inner wall of the second notch, and the other side contacts with the upper surface of the circuit board 300. Specifically, the upper surface of the aluminum nitride ceramic substrate 800 contacts the upper sidewall of the second notch, the lower surface thereof contacts the upper surface of the circuit board 300, and the gaps between the aluminum nitride ceramic substrate 800 and the package 410, and between the aluminum nitride ceramic substrate 800 and the circuit board 300 are filled with the insulating high thermal conductive adhesive. As shown in the heat conduction path, the heat generated by the first light receiving chip 4303 is conducted to the circuit board 300 through the first ceramic substrate 4304, the heat generated by the first transimpedance amplifier 4305 is directly conducted to the circuit board 300, the heat generated by the second light receiving chip 4403 is conducted to the circuit board 300 through the second ceramic substrate 4404, the heat generated by the second transimpedance amplifier 4405 is directly conducted to the circuit board 300, and the heat conducted to the circuit board 300 is conducted to the package 410 through the copper-clad and aluminum nitride ceramic substrates 800 on the circuit board 300, and then conducted to the upper housing 201 and the lower housing 202 of the optical module through the package 410 for heat dissipation, thereby improving the heat dissipation efficiency of the light receiving module integrated in the optical sub-module 400.

The first transimpedance amplifier 4305 and the second transimpedance amplifier 4405 are attached to the circuit board 300, or the first transimpedance amplifier 4305 is attached to a heat sink, and then the heat sink is attached to the upper surface of the circuit board 300, so that the heat sink can not only conduct heat generated by the first transimpedance amplifier 4305 to the circuit board 300, but also heighten the first transimpedance amplifier 4305, so that the first transimpedance amplifier 4305 and the first optical receiving chip 4303 are located on the same plane. Similarly, the second transimpedance amplifier 4405 may be attached to a heat sink, and the heat sink may be attached to the upper surface of the circuit board 300, so that the heat sink can not only conduct the heat generated by the second transimpedance amplifier 4405 to the circuit board 300, but also elevate the second transimpedance amplifier 4405, so that the second transimpedance amplifier 4405 and the second light-receiving chip 4403 are located on the same plane.

In the embodiment of the present application, the light receiving cavity, the slot and the portion of the circuit board 300 inserted into the package 410 all belong to the light receiving portion, the wavelength division demultiplexing component of the light receiving component is disposed in the light receiving cavity, the lens array and the reflection prism are disposed in the slot, and the light receiving chip and the like are disposed on the end surface of the circuit board 300 inserted into the package 410, thereby integrating the light receiving component into the package 410.

In the embodiment of the present application, the optical subassembly 400 has both a light receiving element and a light emitting element integrated therein, the light receiving element and the light emitting element are separated by a partition, the light receiving element is integrated above the partition, and the light emitting element is integrated below the partition.

Fig. 16 is a schematic view illustrating another angle assembly of the circuit board 300 and the optical sub-assembly 400 in the optical module according to the embodiment of the present disclosure, fig. 17 is a schematic view illustrating another angle assembly of the circuit board 300 and the optical sub-assembly 400 in the optical module according to the embodiment of the present disclosure, and fig. 18 is a schematic view illustrating a partial exploded view of the circuit board 300 and the optical sub-assembly 400 in the optical module according to the embodiment of the present disclosure. As shown in fig. 16, 17 and 18, a light emitting cavity and a light emitting cover 403 are disposed at the lower part of the package 410, the light emitting cover 403 is covered in the light emitting cavity from the lower part, and an optoelectronic device related to light emission, such as a lens and a light emitting chip, is disposed in the light emitting cavity, that is, the light emitting cavity is a light emitting part. One side of the package 410 facing the circuit board 300 is provided with a first notch 4114, the circuit board 300 is inserted into the package 410 through the first notch 4114, so that the light emitting chip and other electric devices arranged in the light emitting cavity are electrically connected with the circuit board 300 through a routing so as to drive the light emitting chip to realize electro-optic conversion.

In the optical module provided in the embodiment of the present application, the light emitting component in the optical subassembly 400 is configured to emit multiple signal lights with different wavelengths, the signal lights with different wavelengths are combined through optical devices such as a wavelength division multiplexing component (MUX) in the light emitting cavity, and a combined light beam is transmitted to an external optical fiber through an optical fiber adapter, so as to emit the signal light. Generally, one light emitting chip is used for emitting signal light of one wavelength, and the light emitting assembly provided by the embodiment of the present application includes a plurality of light emitting chips. For example, when the light emitting module is used to emit signal lights of 4 different wavelengths, the light emitting module includes 4 light emitting chips for correspondingly emitting the signal lights of 4 different wavelengths; when the optical transmission assembly is used for transmitting signal light of 8 different wavelengths, the optical transmission assembly comprises 8 optical transmission chips for correspondingly transmitting the signal light of 8 wavelengths.

Fig. 19 is another schematic structural diagram of a package 410 in an optical module according to an embodiment of the present disclosure. As shown in fig. 19, in the optical sub-assembly 400, the optical cavity 4115 includes optical devices such as a wavelength division multiplexing assembly 460, and the optical beams with different wavelengths emitted by the optical transmitter chip are transmitted to the wavelength division multiplexing assembly 460, and the wavelength division multiplexing assembly 460 multiplexes the optical beams with different wavelengths into a composite optical beam, and the composite optical beam is transmitted to an external optical fiber through an optical fiber adapter.

In the embodiment of the present application, the wavelength division multiplexing assembly 460 includes four light inlets on the right side for inputting signal light with multiple wavelengths, and includes one light outlet on the left side for outputting light, where each light inlet is used for inputting signal light with one wavelength. Specifically, a plurality of signal lights with different wavelengths enter the wavelength division multiplexing assembly 460 through corresponding light inlet ports, one signal light reaches the light outlet port after being reflected for six times differently at six different positions of the wavelength division multiplexing assembly 460, one signal light reaches the light outlet port after being reflected for four times differently at four different positions of the wavelength division multiplexing assembly, one signal light reaches the light outlet port after being reflected for two times differently at two different positions of the wavelength division multiplexing assembly, and one signal light is transmitted to the light outlet port directly after being incident to the wavelength division multiplexing assembly 460. Therefore, the wavelength division multiplexing component realizes that the signal lights with different wavelengths enter the wavelength division multiplexing component through different light inlets and are output through the same light outlet, and further realizes the beam combination of the signal lights with different wavelengths. In the embodiment of the present application, the wavelength division multiplexing component is not limited to the combined beam including the 4 wavelength light beams, and can be selected according to actual needs.

The embodiment of the present application provides that it has 2 groups of optical emission subassembly to integrate in the optics submodule 400, the lower part of tube 410 is provided with the optical emission cavity 4115, be provided with convergent lens in this optical emission cavity 4115, wavelength division multiplexing subassembly 460 and optical emission subassembly, the left side of tube 410 is provided with the optical fiber adapter, this optical fiber adapter is linked together with optical emission cavity 4115, wavelength division multiplexing subassembly 460 sets up the one side that is close to the optical fiber adapter at optical emission cavity 4115, the optical emission subassembly sets up the one side that is close to circuit board 300 at optical emission cavity 4115, convergent lens sets up between optical fiber adapter and wavelength division multiplexing subassembly 460. The signal light with different wavelengths emitted by the optical emission component is transmitted to the wavelength division multiplexing component 460, a plurality of light beams with different wavelengths are multiplexed into a composite light beam through the wavelength division multiplexing component 460, and the composite light beam is coupled to the optical fiber adapter through the converging lens, so that the emission of the light with different wavelengths is realized.

Fig. 20 is a schematic structural diagram of a light emitting component in an optical subassembly 400 in an optical module according to an embodiment of the present disclosure, and fig. 21 is a schematic optical path diagram of the light emitting component in the optical module according to the embodiment of the present disclosure. As shown in fig. 20 and 21, the light emitting cavity 4115 includes a bottom plate and a side plate surrounding the bottom plate, the bottom plate and the side plate form a cavity structure for accommodating the wavelength division multiplexing module 460 and the light emitting module, the light emitting module includes a first light emitting module 470 and a second light emitting module 480, the first light emitting module 470 and the second light emitting module 480 are located at one side of the light emitting cavity 4115 close to the circuit board 300, and the first light emitting module 470 and the second light emitting module 480 are electrically connected to the circuit board 300 respectively. The wavelength division multiplexing component 460 disposed in the light emission cavity 4115 includes a first wavelength division multiplexing component 4601 and a second wavelength division multiplexing component 4602, a third fiber adapter 603 and a fourth fiber adapter 604 are disposed on the left side of the package 410, the third fiber adapter 603 extends into the light emission cavity 4115, a first converging lens 701 is disposed between the third fiber adapter 603 and the first wavelength division multiplexing component 4601, and a second converging lens 702 is disposed between the fourth fiber adapter 604 and the second wavelength division multiplexing component 4602. In this way, the 4 signal lights with different wavelengths emitted from the first optical transmission component 470 are transmitted to the first wavelength division multiplexing component 4601, and the 4 signal lights with different wavelengths are multiplexed into one composite light beam via the first wavelength division multiplexing component 4601, and the composite light beam is convergently coupled to the third fiber adapter 603 via the first converging lens 701. Similarly, the 4 signal lights with different wavelengths emitted from the second light emitting component 480 are transmitted to the second wavelength division multiplexing component 4602, and the 4 signal lights with different wavelengths are multiplexed into one composite light beam by the second wavelength division multiplexing component 4602, and the composite light beam is convergently coupled to the fourth fiber adapter 604 by the second converging lens 702.

In the embodiment of the present application, the first optical transmitter 470 and the second optical transmitter 480 respectively include a plurality of optical transmitter chips, and the optical transmitter chips are laser chips for converting the current signal into laser and transmitting the laser. Specifically, the first light emitting assembly 470 includes a third lens array 4701 and a first laser assembly 4702, the first laser assembly 4702 is used for emitting a plurality of signal lights with different wavelengths, the third lens array 4701 is arranged in the emergent light direction of the first laser assembly 4702 for converting the light beam emitted by the first laser assembly 4702 into a collimated light beam; the first wavelength division multiplexing component 4601 is arranged in the outgoing light direction of the third lens array 4701 for multiplexing multiple light beams of different wavelengths into one composite light beam; the first converging lens 701 is disposed in the light exiting direction of the first wavelength division multiplexing component 4601, and is configured to converge and couple one composite light beam exiting from the first wavelength division multiplexing component 4601 into the third fiber adapter 603, so as to implement light emission.

Similarly, the second light emitting module 480 includes a fourth lens array 4801 and a second laser module 4802, the second laser module 4802 is used for emitting a plurality of signal lights with different wavelengths, the fourth lens array 4801 is disposed in the emitting light direction of the second laser module 4802 for converting the light beam emitted from the second laser module 4802 into a collimated light beam; the second wavelength division multiplexing component 4602 is arranged in the emergent light direction of the fourth lens array 4801 and is used for multiplexing multiple light beams with different wavelengths into a composite light beam; the second converging lens 702 is disposed in the light exiting direction of the second wavelength division multiplexing component 4602, and is configured to converge and couple one composite light beam exiting from the second wavelength division multiplexing component 4602 into the fourth fiber adapter 604, so as to implement light emission.

In this embodiment, the first laser assembly 4702 may include 4 lasers, the third lens array 4701 may include 4 collimating lenses, the 4 lasers and the 4 collimating lenses are arranged in a one-to-one correspondence, the 4 lasers respectively emit 4 beams of light with different wavelengths, and the 4 beams of light with different wavelengths are respectively transmitted to the corresponding collimating lenses. Correspondingly, the second laser assembly 4802 may include 4 lasers, the fourth lens array 4801 may include 4 collimating lenses, the 4 lasers and the 4 collimating lenses are disposed in a one-to-one correspondence, the 4 lasers respectively emit 4 light beams with different wavelengths, and the 4 light beams with different wavelengths are respectively transmitted to the corresponding collimating lenses.

The first wavelength division multiplexing component 4601 and the second wavelength division multiplexing component 4602 both comprise 4 input channels, 4 collimated light beams output by 4 collimating lenses of the third lens array 4701 respectively enter the 4 input channels of the first wavelength division multiplexing component 4601, the first wavelength division multiplexing component 4601 converts the 4 channel collimated light beams into a composite light beam, and the composite light beam is converged and coupled to the third optical fiber adapter 603 through the first converging lens 701, so that light emission of 4 channel wavelength division multiplexing is realized. Similarly, 4 collimated light beams output by 4 collimating lenses of the fourth lens array 4801 enter 4 input channels of the second wavelength division multiplexing component 4602, respectively, and the second wavelength division multiplexing component 4602 converts the 4 channel collimated light beams into a composite light beam, and the composite light beam is coupled to the fourth optical fiber adapter 604 through the second converging lens 702 in a converging manner, so that the light emission of the 4 channel wavelength division multiplexing is realized. So, this application is two way composite beam through two wavelength division multiplexing subassemblies with 8 passageway light beam multiplexing, in two way composite beam couples to two fiber adapter respectively, has reduced the volume that occupies of light emission subassembly in the optical module, is favorable to the miniaturized development of optical module.

In this embodiment, in order to implement the emission optical path described in the above embodiment, a platform for supporting and coupling devices needs to be provided for the first light emitting component 470, the first wavelength division multiplexing component 4601, the second light emitting component 480, and the second wavelength division multiplexing component 4602 in the optical path structure, so as to implement the passive coupling of the first light emitting component 470 and the first wavelength division multiplexing component 4601, implement the passive coupling of the second light emitting component 480 and the second wavelength division multiplexing component 4602, and reduce the difficulty in coupling the emission optical path.

Fig. 22 is a schematic view of another angle structure of a package 410 in an optical module according to an embodiment of the present disclosure. As shown in fig. 22, the bottom plate of the light emitting cavity 4115 in the lower part of the housing 410 includes a first bottom surface 4115c and a second bottom surface 4116, a step surface is formed between the first bottom surface 4115c and the second bottom surface 4116, that is, a height difference is formed between the first bottom surface 4115c and the second bottom surface 4116, and the second bottom surface 4116 is sunk below the first bottom surface 4115c. The first bottom surface 4115c is provided with a first MUX fixing glue groove 4117 and a second MUX fixing glue groove 4118, the first wavelength division multiplexing component 4601 is fixed on the first bottom surface 4115c through the first MUX fixing glue groove 4117, and the second wavelength division multiplexing component 4602 is fixed on the first bottom surface 4115c through the second MUX fixing glue groove 4118. Specifically, the first MUX fixing glue groove 4117 is used for holding glue, when the first wavelength division multiplexing component 4601 needs to be fixed, the glue is dispensed in the first MUX fixing glue groove 4117, then the first wavelength division multiplexing component 4601 is mounted on the first MUX fixing glue groove 4117, and the glue is solidified to complete the fixing of the first wavelength division multiplexing component 4601 on the first bottom surface 4115c. Similarly, the second MUX fixing glue groove 4118 is used for holding glue, when the second wavelength division multiplexing component 4602 needs to be fixed, the glue is dispensed in the second MUX fixing glue groove 4118, and then the second wavelength division multiplexing component 4602 is mounted and placed on the second MUX fixing glue groove 4118, and the glue is solidified to complete the fixation of the second wavelength division multiplexing component 4602 on the first bottom surface 4115c.

The second bottom surface 4116 is used for carrying the first light emitting module 470 and the second light emitting module 480, in order to ensure that the heights of the emission channel of the first light emitting module 470 are consistent with the heights of the input channel of the first wavelength division multiplexing module 4601 and the heights of the input channels of the second light emitting module 480 and the second wavelength division multiplexing module 4602, a semiconductor cooler 490 is arranged on the second bottom surface 4116, the bottom surface of the semiconductor cooler 490 is adhered to the second bottom surface 4116, and the top surface of the semiconductor cooler 490 is used for supporting and fixing the first light emitting module 470 and the second light emitting module 480, so that the heat generated by the first light emitting module 470 and the second light emitting module 480 can be transferred to the semiconductor cooler 490, thereby effectively realizing the heat dissipation of the light emitting modules.

A step surface between the first bottom surface 4115c and the second bottom surface 4116 realizes the division of the height of the bottom surface of the light emitting cavity 4115, on one hand, a step surface is formed between the first bottom surface 4115c and the second bottom surface 4116, and the second bottom surface 4116 can relatively reduce the height of the mounting surface of the semiconductor cooler 490, so as to reduce the heights of the first light emitting component 470 and the second light emitting component 480, which facilitates the assembly of the first light emitting component 470, the first wavelength division multiplexing component 4601, the second light emitting component 480 and the second wavelength division multiplexing component 4602; on the other hand, the step surface can also be used for limiting the semiconductor cooler 490.

The first notch 4114 disposed on one side of the package 410 close to the circuit board 300 is wrapped on the outer side of the second bottom surface 4116, the third notch 310 is disposed on one side of the circuit board 300 facing the package 410, when the circuit board 300 is inserted into the first notch 4114 of the package 410, the two side walls of the third notch 310 wrap the second bottom surface 4116, so that the distance between the light emitting component on the second bottom surface 4116 and the circuit board 300 can be shortened, when the first laser component 4702 and the second laser component 4802 are electrically connected to the circuit board 300 through a wire bonding, the length of the wire bonding between the first laser component 4702 and the second laser component 4802 and the circuit board 300 can be reduced.

Fig. 23 is an assembly cross-sectional view of a light emitting module and a package 410 in an optical module according to an embodiment of the present disclosure. As shown in fig. 23, the second bottom surface 4116 is located below the light passing hole 4109 on the housing 410, one side surface of the semiconductor cooler 490 is adhered to the second bottom surface 4116, and the first light emitting assembly 470 and the second light emitting assembly 480 are adhered to the other side surface of the semiconductor cooler 490. The first light emitting assembly 470 and the second light emitting assembly 480 share 8 lasers, heat generated by the lasers is conducted to the semiconductor cooler 490, and the heat of the semiconductor cooler 490 can be conducted to the upper surface of the case 410 from a place where no hole is drilled on the case 410 by avoiding the light through hole 4109, and then conducted to the optical module case through a heat conducting material for heat dissipation.

In the embodiment of the present application, the light passing hole 4109 is used at a light receiving end for transmitting the light beams output by the wavelength division demultiplexing component through demultiplexing to the lens array, and each light beam output by the wavelength division demultiplexing component is guided to a corresponding collimating lens through one light passing hole 4109; logical unthreaded hole 4109 is used for making things convenient for the heat-conduction of light emission subassembly at the end of emitting light, avoids logical unthreaded hole 4109 on the tube 410 promptly after, and the upper and lower part of tube 410 is integrative, and the heat that the end of emitting light produced like this can be followed the place conduction that does not have drilling on the tube 410 and radiated to the tube upper surface, and the rethread heat conduction material conducts and dispels the heat on the optical module shell, as the arrow shows, has improved the radiating efficiency of the end of emitting light.

A third through hole 4119 and a fourth through hole 4120 are formed in one side of the tube housing 410, which is close to the optical fiber adapter, the third through hole 4119 and the fourth through hole 4120 are both communicated with the light emitting cavity 4115, and the third optical fiber adapter 603 is inserted into the light emitting cavity 4115 through the third through hole 4119 to receive a converging light beam output by the first converging lens 701; the fourth fiber optic adapter 604 is inserted into the light emitting cavity 4115 through the fourth through hole 4120 to receive one of the converging light beams output by the second converging lens 702.

In this embodiment, the light emitting cavity 4115 includes a bottom plate and side plates surrounding the bottom plate, the bottom plate and the side plates surround to form a cavity structure for accommodating the first light emitting module 470, the first wavelength division multiplexing module 4601, the first focusing lens 701, the second light emitting module 480, the second wavelength division multiplexing module 4602 and the second focusing lens 702, a third cover fixing glue groove 4115a is disposed on the top of the side plate of the light emitting cavity 4115, and the light emitting cover 403 can be fixedly connected to the light emitting cavity 4115 by glue. Optionally, the third cover plate fixing glue groove 4115a forms a closed loop structure at the top of the side plate of the light emission cavity 4115, so that the glue area of the light emission cover plate 403 at the top of the side plate of the light emission cavity 4115 can be increased, and the packaging reliability of the light emission cover plate 403 and the top of the side plate of the light emission cavity 4115 can be fully ensured. Furthermore, a third repairing port 4115b is further disposed on the top of the side plate of the light emission cavity 4115, the third repairing port 4115b is disposed on the edge of the top of the side plate of the light emission cavity 4115, and the third repairing port 4115b is communicated with a third cover plate fixing glue groove 4115a. When the internal devices of the light emission cavity 4115 need to be repaired after the light emission cover plate 403 and the light emission cavity 4115 are packaged, the light emission cover plate 403 can be detached from the light emission cavity 4115 through the third repairing port 4115b, so that the light emission cover plate 403 can be detached without damaging the light emission cover plate 403 or the light emission cavity 4115, and the repairing difficulty and cost are reduced.

The optical module provided by the embodiment of the application adopts a common metal outer pipe shell, the pipe shell is provided with openings from the upper surface and the lower surface, the light emitting assembly and the light receiving assembly are respectively arranged on the pipe shell, and the light emitting assembly and the light receiving assembly are structurally arranged in a back-to-back layout, namely the light emitting assembly and the light receiving assembly share a partition plate in the middle of the pipe shell, the light receiving assembly is arranged on the upper side of the partition plate, and the light emitting assembly is arranged on the lower side of the partition plate; one end of the circuit board is inserted into the tube shell, and the high-frequency wiring of the light emitting assembly and the light receiving assembly respectively runs through the upper surface and the lower surface of the circuit board, so that the cross influence is avoided. The light emitting assembly and the light receiving assembly are of an integrated structure, so that the problem that the whole space of an optical module adopting the discrete light emitting assembly and the light receiving assembly is insufficient can be solved, and the miniaturization development of the optical module is facilitated.

It should be noted that, in the present specification, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a circuit structure, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such circuit structure, article, or apparatus. Without further limitation, the phrases "comprising a" \8230; "defining an element do not exclude the presence of additional like elements in a circuit structure, article, or device comprising the element.

Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.

The above-described embodiments of the present application do not limit the scope of the present application.

Claims

1. A light module, comprising:

a circuit board, one end of which is provided with a third gap;

the device comprises a shell, a first light receiving cavity, a second light receiving cavity and a light emitting cavity, wherein the two opposite side surfaces of the shell are respectively provided with an opening, and the light receiving cavity and the light emitting cavity are arranged back to back respectively; a plurality of light through holes are formed in one end, close to the circuit board, of the tube shell, and the first light receiving cavity and the second light receiving cavity are communicated with the light through holes respectively; the circuit board is inserted into the tube shell;

the plurality of light receiving components are respectively arranged in the first light receiving cavity and the second light receiving cavity and are electrically connected with the circuit board;

the optical fiber adapters are arranged on one side, far away from the circuit board, of the tube shell, one optical fiber adapter is communicated with the first light receiving cavity, the other optical fiber adapter is communicated with the second light receiving cavity, and the rest optical fiber adapters are communicated with the light emitting cavity;

the light emitting assemblies are arranged in the light emitting cavity side by side and are electrically connected with the circuit board; the optical fiber laser comprises a wavelength division multiplexing component, a lens array and a laser component, wherein the laser component, the lens array and the wavelength division multiplexing component are sequentially arranged along a light emission light path, and the laser component is wrapped by the inner side wall of the third notch; the laser assembly is positioned below the light through hole and used for emitting a plurality of light beams with different wavelengths and conducting heat generated by the laser assembly to the surface of the tube shell by avoiding the light through hole; the lens array is used for converting the multiple beams of light beams into multiple collimated beams of light; the wavelength division multiplexing assembly is used for multiplexing a plurality of collimated light beams into a composite light beam and coupling the composite light beam to the optical fiber adapter.

2. The optical module of claim 1, wherein a first laser component, a third lens array, a first wavelength division multiplexing component, a second laser component, a fourth lens array, and a second wavelength division multiplexing component are disposed within the light emission cavity, the first wavelength division multiplexing component and the second wavelength division multiplexing component being disposed in parallel; the first laser assembly, the third lens array and the first wavelength division multiplexing assembly are sequentially arranged along a light emission optical path, and the second laser assembly, the fourth lens array and the second wavelength division multiplexing assembly are sequentially arranged along the light emission optical path;

and a third optical fiber adapter and a fourth optical fiber adapter are arranged on one side of the tube shell, which is far away from the circuit board, the third optical fiber adapter is arranged on the output light path of the first wavelength division multiplexing component, and the fourth optical fiber adapter is arranged on the output light path of the second wavelength division multiplexing component.

3. The light module as claimed in claim 2, wherein the bottom plate of the light emitting cavity comprises a first bottom surface and a second bottom surface, the second bottom surface is recessed from the first bottom surface, and the second bottom surface is located below the light passing hole;

the first laser assembly, the third lens array, the second laser assembly and the fourth lens array are all fixed on the second bottom surface, and the first wavelength division multiplexing assembly and the second wavelength division multiplexing assembly are all fixed on the first bottom surface.

4. The optical module of claim 3, wherein a semiconductor cooler is disposed on the second bottom surface, the bottom surface of the semiconductor cooler is bonded to the second bottom surface, and the first laser assembly, the third lens array, the second laser assembly and the fourth lens array are fixed on opposite sides of the semiconductor cooler, so that the emission channels of the first laser assembly and the input channels of the first wavelength division multiplexing assembly, and the emission channels of the second laser assembly and the input channels of the second wavelength division multiplexing assembly have the same height.

5. The optical module according to claim 3, wherein a first MUX fixing glue groove and a second MUX fixing glue groove are provided on the first bottom surface, the first wavelength division multiplexing module is fixed on the first bottom surface through the first MUX fixing glue groove, and the second wavelength division multiplexing module is fixed on the first bottom surface through the second MUX fixing glue groove.

6. The optical module according to claim 3, wherein a side of the case close to the circuit board is provided with a first notch through which the circuit board is inserted into the case; and a third notch is formed in one side, inserted into the tube shell, of the circuit board, and two side walls of the third notch wrap the second bottom surface.

7. The optical module of claim 6, wherein the light receiving chip of the light receiving module is disposed on one side of the circuit board inserted into the package, and the laser module is connected to the other side of the circuit board by wire bonding.

8. The optical module according to claim 2, wherein a first converging lens and a second converging lens are further disposed in the light emitting cavity, and the first converging lens is disposed between the first wavelength division multiplexing component and the third optical fiber adapter, and configured to converge and couple the composite light beam output by the first wavelength division multiplexing component to the third optical fiber adapter; the second converging lens is arranged between the second wavelength division multiplexing component and the fourth optical fiber adapter and is used for converging and coupling the composite light beam output by the second wavelength division multiplexing component to the fourth optical fiber adapter.

9. The optical module of claim 8, wherein a side of the package near the third fiber optic adapter is provided with a third through hole, and the third fiber optic adapter is inserted into the light emission cavity through the third through hole;

and a fourth through hole is formed in one side, close to the fourth optical fiber adapter, of the tube shell, and the fourth optical fiber adapter is inserted into the light emission cavity through the fourth through hole.

10. The optical module according to claim 1, wherein the light receiving portion further comprises a slit adjacent to the circuit board, and a plurality of the light passing holes are provided between a light receiving cavity and the slit.