WO2021218464A1

WO2021218464A1 - Optical module

Info

Publication number: WO2021218464A1
Application number: PCT/CN2021/080966
Authority: WO
Inventors: 李丹; 傅钦豪; 谢一帆; 崔峰; 付孟博
Original assignee: 青岛海信宽带多媒体技术有限公司
Priority date: 2020-04-29
Filing date: 2021-03-16
Publication date: 2021-11-04
Also published as: CN113568113A

Abstract

An optical module (200), comprising: a circuit board (300); and a light receiving sub-module (500), which is used to convert received signal light into a current signal. The light receiving sub-module (500) comprises several photoelectric conversion assemblies (505). Each photoelectric conversion assembly (505) comprises: a first pad (5051) which is disposed on the circuit board (300) and provided with a circuit (511) on a front surface; and a photodetector (5052), a front surface of which is provided with a photosensitive surface (521) and an electrode (522), the front surface is connected to the front side surface of the first pad (5051) and the electrode (522) is connected to one end of the circuit (511), a back surface is far away from the first pad (5051) and is formed with a lens (523) for converging signal light to the photosensitive surface (521), and the photodetector (5052) is used to convert the received signal light into a current signal. The optical module (200) further comprises: a transimpedance amplifier (302), which is disposed on the circuit board (300), and is in wire-bonding connected to the other end of the circuit (511) on the first pad (5051) to convert the current signal into a voltage signal and send same to the circuit board (300). The back-illuminated combination lens (523) of the photodetector (5052) reduces the coupling difficulty when the photodetector (5052) receives a light signal, and improves the coupling efficiency with which the optical module (200) receives the signal light.

Description

An optical module

The present disclosure requires priority to be submitted to the Chinese Patent Office on April 29, 2020, with an application number of 202010353506.6 and a patent title of "an optical module", the entire content of which is incorporated into the present disclosure by reference.

Technical field

The present disclosure relates to the field of optical communication technology, and in particular to an optical module.

Background technique

In cloud computing, mobile Internet, video and other new business and application modes, optical communication technology will be used. In optical communication, the optical module is a tool to realize the mutual conversion of photoelectric signals, and it is one of the key components in optical communication equipment. And with the rapid development of 5G networks, optical modules at the core of optical communications have made considerable progress.

Summary of the invention

An optical module provided by the present disclosure includes: a circuit board; a light receiving sub-module electrically connected to the circuit board for converting received signal light into a current signal; the light receiving sub-module includes a number of photoelectric Conversion component; the photoelectric conversion component includes: a first pad, arranged on the circuit board, the front side is provided with a circuit; a photodetector, the front side is provided with a photosensitive surface and an electrode, and the front side is connected to the front side of the first pad And the electrode is connected to one end of the circuit, the back is far away from the first gasket and a lens for converging signal light to the photosensitive surface is formed, for converting the received signal light into a current signal; the light The module further includes: a transimpedance amplifier, which is arranged on the circuit board, and is connected to the other end of the circuit on the first pad by wire, converts the current signal into a voltage signal and sends it to the circuit board.

Description of the drawings

In order to explain the technical solutions of the present disclosure more clearly, the following will briefly introduce the drawings needed in the embodiments. Obviously, for those of ordinary skill in the art, without creative labor, Other drawings can also be obtained from these drawings.

Figure 1 is a schematic diagram of the connection relationship of an optical communication terminal;

Figure 2 is a schematic diagram of the structure of an optical network unit;

FIG. 3 is a schematic structural diagram of an optical module provided by an embodiment of the disclosure;

4 is a schematic diagram of an exploded structure of an optical module provided by an embodiment of the disclosure;

FIG. 5 is a schematic diagram of a partial structure of an optical module provided by an embodiment of the disclosure;

6 is a schematic diagram of a partial structure of another optical module provided by an embodiment of the disclosure;

FIG. 7 is a perspective view of a photoelectric conversion component provided by an embodiment of the disclosure;

FIG. 8 is a schematic diagram 1 of an exploded structure of a photoelectric conversion component provided by an embodiment of the present disclosure;

FIG. 9 is a second schematic diagram of an exploded structure of a photoelectric conversion component provided by an embodiment of the disclosure;

10 is an exploded schematic diagram of a partial structure of an optical module provided by an embodiment of the disclosure;

Figure 11 is a partial enlarged view of A in Figure 5;

Figure 12 is a partial enlarged view at B in Figure 6;

FIG. 13 is a schematic diagram of a partial structure in still another optical module provided by an embodiment of the disclosure.

Detailed ways

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present disclosure.

One of the core links of optical communication is the mutual conversion of optical and electrical signals. Optical communication uses information-carrying optical signals to be transmitted in information transmission equipment such as optical fibers/optical waveguides, and the passive transmission characteristics of light in optical fibers/optical waveguides can realize low-cost and low-loss information transmission; and information processing equipment such as computers Electrical signals are used. In order to establish an information connection between information transmission equipment such as optical fibers/optical waveguides and information processing equipment such as computers, it is necessary to realize mutual conversion between electrical signals and optical signals.

The optical module realizes the above-mentioned mutual conversion function of optical and electrical signals in the field of optical fiber communication technology, and the mutual conversion of optical signals and electrical signals is the core function of the optical module. The optical module realizes the electrical connection with the external host computer through the golden finger on its internal circuit board. The main electrical connections include power supply, I2C signal, data signal and grounding, etc.; the electrical connection method realized by the golden finger has become the optical module The mainstream connection method of the industry, based on this, the definition of the pins on the golden finger has formed a variety of industry protocols/standards.

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

One end of the optical fiber 101 is connected to the remote server, and one end of the network cable 103 is connected to the local information processing equipment. The connection between the local information processing equipment and the remote server is completed by the connection of the optical fiber 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is The optical network unit 100 with the optical module 200 is completed.

The optical port of the optical module 200 is connected to the optical fiber 101, and a bidirectional optical signal connection is established with the optical fiber. The electrical port of the optical module 200 is connected to the optical network unit 100 to establish a two-way electrical signal connection with the optical network unit. The optical module realizes the mutual conversion between optical signals and electrical signals, thereby realizing the establishment of a connection between the optical fiber 101 and the optical network unit 100.

In an embodiment of the present disclosure, the optical signal from the optical fiber is converted into an electrical signal by the optical module and then input into the optical network unit 100, and the electrical signal from the optical network unit 100 is converted into an optical signal by the optical module and input into the optical fiber 101 middle. The optical module 200 is a tool for realizing the mutual conversion of photoelectric signals, and does not have the function of processing data. In the foregoing photoelectric conversion process, the carrier of information is converted between light and electricity, but the information itself has not changed.

The optical network unit 100 has an optical module interface 102 for connecting to the optical module 200 and establishing a bidirectional electrical signal connection with the optical module 200. The optical network unit has a network cable interface 104, which is used to connect to the network cable 103 and establish a two-way electrical signal connection with the network cable 103; the optical module 200 and the network cable 103 establish a connection through the optical network unit. In an embodiment of the present disclosure, the optical network unit transmits the 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 unit acts as the upper computer of the optical module to monitor the operation of the optical module.

So far, the remote server establishes a bidirectional signal transmission channel with the local information processing equipment through the optical fiber 101, the optical module 200, the optical network unit 100, and the network cable 103 in sequence.

Common information processing equipment includes routers, switches, electronic computers, etc.; the optical network unit is the upper computer of the optical module, which provides data signals to the optical module and receives data signals from the optical module. The common optical module upper computer also has optical lines Terminal OLT, etc.

Figure 2 is a schematic diagram of the optical network unit structure. As shown in Figure 2, the optical network unit 100 has a circuit board 105, and a cage 106 is provided on the surface of the circuit board 105; an electrical connector connected to the circuit board 105 is provided in the cage 106 for accessing golden fingers, etc. Optical module electrical port; a radiator 107 is provided on the cage 106, and the radiator 107 has a convex structure such as fins to increase the heat dissipation area.

The optical module 200 is inserted into the optical network unit 100. Specifically, the electrical port of the optical module is inserted into the electrical connector in the cage 106, and the optical port of the optical module is connected to the optical fiber 101.

The cage 106 is located on the circuit board 105 of the optical network unit 100 and wraps the electrical connectors on the circuit board 105 in the cage; the optical module is inserted into the cage, and the optical module is fixed by the cage, and the heat generated by the optical module is conducted through the optical module housing Give it to the cage, and finally spread through the radiator 107 on the cage.

Fig. 3 is a schematic structural diagram of an optical module provided by an embodiment of the present disclosure, and Fig. 4 is an exploded schematic diagram of an optical module structure provided by an embodiment of the present disclosure. As shown in Figs. 3 and 4, the optical module provided by the embodiment of the present disclosure 200 includes an upper housing 201, a lower housing 202, an unlocking handle 203, a circuit board 300, a light emitting sub-module 400, a light receiving sub-module 500, and an optical fiber socket 502.

The upper shell 201 and the lower shell 202 form a wrapping cavity with two ports, which can be two ports (204, 205) in the same direction, or two ports in different directions; one of the ports is The electrical port 204 is used to plug into the upper computer such as the optical network unit; the other port is the optical port 205, which is used to connect the external optical fiber 101; the circuit board 300, the optical transmitting sub-module 400 and the optical receiving sub-module 500 and other optoelectronic devices are located on the upper , In the wrapping cavity formed by the lower shell.

The upper shell and the lower shell are generally made of metal materials, which is conducive to electromagnetic shielding and heat dissipation; the assembly method of the upper shell and the lower shell is used to facilitate the installation of circuit boards and other components into the shell. Generally, optical modules are not used. The housing is made into an integrated structure, so that when assembling circuit boards and other devices, the positioning components, heat dissipation and electromagnetic shielding structures are not easy to install, which is not conducive to production automation.

The unlocking handle 203 is located on the outer wall of the wrapping cavity/lower housing 202. Pulling the end of the unlocking handle can make the unlocking handle move relatively on the outer wall surface; when the optical module is inserted into the upper computer, the unlocking handle 203 is engaged with the cage 106, thereby holding the optical module It is fixed in the upper computer; the locking relationship between the optical module 200 and the cage 106 is released by pulling the unlocking handle, so that the optical module can be withdrawn from the upper computer.

The circuit board 300 is located in an enveloping cavity formed by an upper shell and a shell. The circuit board 300 is electrically connected to the light emitting sub-module 400 and the light receiving sub-module 500 respectively. The circuit board is provided with electrical devices such as chips, capacitors, and resistors. Choose the corresponding chip according to the needs of the product. Common chips include microprocessor MCU, clock data recovery chip CDR, laser driver chip, transimpedance amplifier TIA chip, limiting amplifier LA chip, power management chip, etc. Among them, the transimpedance amplifier is closely related to the light detection chip. Some products will package the transimpedance amplifier and the light detection chip together, such as in the same TO package or the same shell; the light detection chip and the transimpedance amplifier can also be separated Separately install the transimpedance amplifier on the circuit board.

The chip on the circuit board 300 can be a multifunctional integrated chip, for example, a laser driver chip and an MCU chip are fused into one chip, or a laser driver chip, a limiting amplifier chip, and an MCU can be fused into one chip. The chip is an integrated circuit , But the function of each circuit has not disappeared because of the collection, but the appearance of the circuit has changed, and the circuit form is still present in the chip. Therefore, when the circuit board is provided with three independent chips, the MCU, the laser driver chip, and the limiting amplifier chip, this is the same as setting a single chip with three functions in one on the circuit board 300. The solution is equivalent.

The end surface of the circuit board 300 has golden fingers. The golden fingers are composed of independent pins. The circuit board is inserted into the electrical connector in the cage, and the golden fingers are conductively connected to the snap-fitting shrapnel in the electrical connector. ; Gold fingers can be set on only one side surface of the circuit board. Considering the large number of pins, gold fingers are generally set on the lower surface of the circuit board; the gold fingers are used to establish electrical connections with the upper computer. In this disclosure In a certain embodiment, the electrical connection may be power supply, grounding, I2C signal, communication data signal, etc.

The optical module also includes an optical emission sub-module and an optical receiving sub-module, and the optical emission sub-module and the optical receiving sub-module can be collectively referred to as an optical sub-module. As shown in FIG. 4, the optical module provided by the embodiment of the present disclosure includes a light emitting sub-module 400 and a light receiving sub-module 500. The light emitting sub-module 400 is located on the edge of the circuit board 300, and the light emitting sub-module 400 and the light receiving sub-module 500 are The staggered arrangement on the surface of the circuit board 300 is conducive to achieving a better electromagnetic shielding effect.

The light emitting sub-module 400 is arranged on the surface of the circuit board 300. In another common packaging method, the light emitting sub-module is physically separated from the circuit board, and the electrical connection is achieved through a flexible board. In the embodiment of the present disclosure, the light emitting sub-module 400 is connected to the first optical fiber socket 402 through the first optical fiber 401.

The light emitting sub-module is located in the wrapping cavity formed by the upper and lower shells. As shown in FIG. 4, the circuit board 300 is provided with a notch 301 for placing the light emitting sub-module; the notch 301 can be set in the middle of the circuit board, It can also be arranged on the edge of the circuit board; the light emission sub-module is embedded in the gap 301 of the circuit board, so that the circuit board can be inserted into the light emission sub-module, and it is also convenient to fix the light emission sub-module and the circuit board together. .

The light-receiving sub-module 500 is arranged on the surface of the circuit board 300. In another common packaging method, the light-receiving sub-module is physically separated from the circuit board and is electrically connected through a flexible board. In the embodiment of the present disclosure, the light receiving sub-module 500 is connected to the second optical fiber socket 502 through the second optical fiber 501. The signal light outside the optical module is transmitted to the second optical fiber socket 502 through the external optical fiber, transmitted to the second optical fiber 501, and then transmitted to the light receiving sub-module 500 through the second optical fiber 501, and the receiving sub-module 500 converts the received signal light into electric current Signal. In an embodiment of the present disclosure, the light receiving sub-module 500 includes an optical device and a photoelectric conversion device. Among them, optical devices such as optical fiber connectors, arrayed waveguide gratings, lenses, etc. The second optical fiber 501 transmits the signal light to the optical device, then converts the optical device to the signal light beam transmission path, and finally transmits it to the optoelectronic device.

In an embodiment of the present disclosure, in the embodiment of the present disclosure, the light receiving sub-module 500 includes a photoelectric conversion component. The photoelectric conversion component includes a photodetector. The front of the photodetector includes a photosensitive surface and electrodes. The photosensitive surface is used to receive light and perform photoelectric conversion, and then output through the electrodes. In order to reduce the difficulty of coupling when the photodetector receives the light signal and improve the coupling efficiency of the signal light received by the optical module, a lens is formed on the back of the photodetector, and the signal light transmitted to it is concentrated to the photosensitive surface through the lens, which is equivalent to increasing The area of the photosensitive surface. Furthermore, in the photodetector in the embodiment of the present disclosure, the front of the photodetector faces the circuit board 300. The electrodes of the photodetector and other electrical devices are usually connected by wire bonding. When the front of the photodetector faces the circuit board 300, it is not conducive to wire the electrodes of the photodetector to other electrical devices, which is convenient for the electrodes of the photodetector. For wire bonding, the photoelectric conversion assembly further includes a first gasket.

In an embodiment of the present disclosure, the first pad is disposed on the circuit board 300, the back of the first pad is fixedly connected to the circuit board 300, and the front of the first pad is provided with a circuit. The photodetector is flip-chip welded on the front side of the first pad, that is, the front side of the photodetector is welded to the front side of the first pad, and the electrode on the front side of the photodetector is connected to the circuit on the first pad by connecting The chip realizes the transfer of the upper electrode of the photodetector, thereby facilitating the electrical connection between the photodetector and other devices.

FIG. 5 is a schematic diagram of a partial structure of an optical module provided by an embodiment of the disclosure. As shown in FIG. 5, the light receiving sub-module 500 includes a photoelectric conversion component 505, and the photoelectric conversion component 505 is disposed on the circuit board 300. The photoelectric conversion component 505 is used to convert the received signal light into a current signal. A transimpedance amplifier 302 is provided on the side of the photoelectric conversion component 505. The transimpedance amplifier 302 is provided on the circuit board 300. The transimpedance amplifier 302 is connected to the photoelectric conversion component 505, receives the current signal generated by the photoelectric conversion component 505 and converts the received current signal into a voltage signal, and then sends the voltage signal to the circuit board 300, and finally transmits it through the circuit board 300.

In the embodiment of the present disclosure, the optical receiving sub-module 500 can receive signal light of several different wavelengths, such as one channel, two channels, three channels, or four channels. Therefore, in an embodiment of the present disclosure, the number of photoelectric conversion components 505 in the light receiving sub-module 500 is more than one, and may also be two, three, or four.

Several pins are provided on the top surface of the transimpedance amplifier 302, and the photoelectric conversion component 505 and the transimpedance amplifier 302 are connected by wire bonding. In the embodiments of the present disclosure, the connection can be made through a semiconductor bonding alloy wire (Gold Wire Bonding). However, the greater the wire bonding length, the greater the inductance generated by the wire bonding, and the greater the signal mismatch, and the signal output by the photoelectric conversion component 505 is a small signal, which will cause the signal quality to decrease. Therefore, the photoelectric conversion component 505 and the transimpedance amplifier 302 are as close as possible to reduce the wire length and ensure the signal transmission quality.

FIG. 6 is a schematic diagram of a partial structure of another optical module provided by an embodiment of the disclosure. As shown in FIG. 6, the light receiving submodule 500 provided by the embodiment of the present disclosure includes four photoelectric conversion components 505.

As shown in FIGS. 5 and 6, the light receiving sub-module 500 further includes an arrayed waveguide grating 504. The arrayed waveguide grating 504 can split the received signal light according to the light wavelength. The split signal light is transmitted to the corresponding photoelectric conversion component 505. When the light receiving sub-module 500 includes 4 photoelectric conversion components 505, the signal light will include signal light of 4 wavelengths, and the arrayed waveguide grating 504 will divide the received signal light into 4 signal lights according to the light wavelength. The split beams are transmitted to the photoelectric conversion component 505 in a one-to-one correspondence.

In an embodiment of the present disclosure, a fiber connector 503 is provided at one end of the arrayed waveguide grating 504, and an inclined surface 5041 is provided at the other end. The signal light passing through the optical fiber connector 503 is transmitted to the arrayed waveguide grating 504, is split and transmitted to the inclined surface 5041 via the arrayed waveguide grating 504, and then is reflected to the photoelectric conversion component 505 via the inclined surface 5041. Therefore, the arrayed waveguide grating 504 in the embodiment of the present disclosure can not only perform signal light beam splitting, but also change the transmission direction of signal light.

In the embodiment of the present disclosure, the optical fiber connector 503 includes a tube shell and an optical fiber ferrule. The optical fiber ferrule is arranged in the tube shell, and the optical fiber ferrule is connected to the second optical fiber 501 to facilitate the insertion and fixation of the second optical fiber 501.

To facilitate the fixing of the arrayed waveguide grating 504, the light receiving sub-module 500 further includes a third spacer 506. One side of the third spacer 506 is fixedly arranged on the circuit board 300, and the other side supports and connects the arrayed waveguide grating 504. The third gasket 506 may be a glass gasket or a ceramic gasket. In an embodiment of the present disclosure, the third spacer 506 and the arrayed waveguide grating 504 can be connected by UV glue.

FIG. 7 is a perspective view of a photoelectric conversion component 505 provided by an embodiment of the disclosure. As shown in FIG. 7, the photoelectric conversion assembly 505 includes a first pad 5051 and a photodetector 5052. The photodetector 5052 is disposed above the first spacer 5051. The first gasket 5051 is a metalized ceramic gasket. The surface of the metalized ceramic forms a circuit pattern, which can supply power and signal transmission to the photodetector 5052. At the same time, the metalized ceramic has better thermal conductivity and can be used as the heat of the photodetector 5052. Shen conducts heat dissipation. In an embodiment of the present disclosure, as shown in FIG. 7, the side of the first pad 5051 that is connected to the photodetector 5052 is provided with a circuit pin for connecting the photodetector 5052 to the transimpedance amplifier.

FIG. 8 is a schematic diagram 1 of an exploded structure of a photoelectric conversion module 505 provided by an embodiment of the present disclosure, and FIG. 9 is a schematic diagram 2 of an exploded structure of a photoelectric conversion module 505 provided by an embodiment of the disclosure. As shown in FIG. 8, a circuit 511 is provided on the top surface of the first pad 5051. The circuit 511 is used for the power supply and signal output of the photodetector 5052. As shown in FIGS. 8 and 9, the front surface of the photodetector 5052 includes a photosensitive surface 521 and an electrode 522 for power supply and signal output of the photodetector 5052, and a lens 523 is provided on the back of the photodetector 5052. One end of the circuit 511 is connected to the electrode 522 on the photodetector 5052, and the other end is connected to a pad. The pad is wired to the transimpedance amplifier to realize the electrical connection between the photodetector 5052 and the transimpedance amplifier. Therefore, the first spacer 5051 is used to facilitate the realization of the back-illuminated design of the photodetector 5052.

The lens 523 is used to converge the signal light transmitted therethrough to the photosensitive surface 521. In an embodiment of the present disclosure, the focal point of the lens 523 is located on the photosensitive surface 521, and the light passing through the lens 523 is condensed to the photosensitive surface 521 to the greatest extent. For example, the signal light transmitted to the lens 523 through the arrayed waveguide grating, the signal light passes through the lens 523, and is condensed to the photosensitive surface 521 through the lens 523. It is well known that the photosensitive surface of the existing conventional 100G photodetector is smaller than that of the 25G photodetector. If the existing conventional photodetector is directly used, it will increase the difficulty of coupling the signal light to the photodetector. The photoelectric conversion component 505 in the present disclosure is designed with a back-illuminated photodetector 5052 and a lens 523 is arranged on the back of the photodetector 5052, which is equivalent to increasing the photosensitive surface area of the photodetector. In this way, the photoelectric conversion component 505 provided by the present disclosure can reduce the difficulty of coupling the signal light of the photodetector used in the 100G optical module.

FIG. 10 is an exploded schematic diagram of a partial structure of an optical module provided by an embodiment of the disclosure. As shown in FIG. 10, the back side of the first pad 5051 is used to connect the circuit board 300, and the photodetector 5052 is back-illuminated on the front side of the first pad 5051.

In the embodiment of the present disclosure, in order to facilitate the production of the photoelectric conversion assembly 505, the thickness of the first spacer 5051 is generally greater than the thickness of the photodetector 5052. Then when the photodetector 5052 is placed on the first spacer 5051, the height of the photodetector 5052 will be raised. However, the original transimpedance amplifier and the photodetector are directly arranged on the circuit board, and the wiring pins of the transimpedance amplifier 302 and the electrode pins of the photodetector are almost at the same height, so after raising the photodetector 5052 , Will cause the plane of the circuit pins of the first pad 5051 to connect to the photodetector 5052 to be higher than the plane of the wire bonding pins of the transimpedance amplifier 302, that is, the plane of the circuit pins of the first pad 5051 and The plane where the wire bonding pins of the transimpedance amplifier 302 are located has a height difference. If there is a height difference between the plane of the circuit pins of the first pad 5051 and the plane of the wire bonding pins of the transimpedance amplifier 302, the wire bonding will increase the wire length, which will result in a photodetector. The quality of the 5052 output signal is reduced, which will result in insufficient sensitivity margin of the optical module.

To solve the above-mentioned problem, in an embodiment of the present disclosure, a second spacer is provided under the transimpedance amplifier. The bottom of the second spacer is fixedly connected to the circuit board, and the top of the second spacer is supported and connected to the transimpedance amplifier. The second gasket is arranged under the transimpedance amplifier to raise the plane where the wire bonding pins of the transimpedance amplifier are located, thereby shortening the wire bonding length between the circuit pins of the first gasket and the wire bonding pins of the transimpedance amplifier. Ensure the quality of the signal transmitted between the photodetector and the transimpedance amplifier.

Fig. 11 is a partial enlarged view of A in Fig. 5. As shown in FIG. 11, the second pad 304 is fixedly arranged on the circuit board 300, the second pad 304 is arranged on the side of the first pad 5051, and the transimpedance amplifier 302 is arranged above the second pad 304. The second spacer 304 fixes and raises the transimpedance amplifier 302, so as to shorten the wire length between the circuit pins of the first spacer 5051 and the pins of the transimpedance amplifier 302.

In an embodiment of the present disclosure, the second spacer 304 raises the transimpedance amplifier 302 so that the top surface of the transimpedance amplifier 302 and the front surface of the first spacer 5051 are at the same height above the circuit board 300, so that the first The circuit pins of the spacer 5051 and the wire bonding pins of the transimpedance amplifier 302 are located at the same height above the circuit board 300. In this way, the wire bonding length between the circuit pin of the first pad 5051 and the wire bonding pin of the transimpedance amplifier 302 is effectively shortened, and the quality of the signal transmitted between the photodetector 5052 and the transimpedance amplifier 302 is ensured.

In an embodiment of the present disclosure, the transimpedance amplifier 302 is fixedly connected to the second pad 304 by conductive silver glue. After the second gasket 304 is fixedly arranged on the circuit board 300, the top surface of the second gasket 304 is coated with conductive silver glue, the transimpedance amplifier 302 is placed on the second gasket 304, and the transimpedance amplifier 302 is pressed The conductive silver glue partially overflows and flows along the second pad 304 to the circuit board 300, and then the circuit board can be connected. The transimpedance amplifier 302 is electrically connected to the circuit board 300 through the conductive silver glue that overflows and flows along the second gasket 304 to the circuit board 300, so that the negative electrode of the transimpedance amplifier 302 is grounded through the conductive silver glue.

In the embodiment of the present disclosure, the height of the second gasket 304 can be selected in combination with the height of the first gasket 5051. Generally, the height of the second spacer 304 is about 100 μm. In an embodiment of the present disclosure, the second gasket 304 may be a ceramic gasket, such as an aluminum nitride gasket. The ceramic gasket has better thermal conductivity and can be used as a heat sink of the transimpedance amplifier 302 to dissipate heat.

When the light receiving sub-module includes more than one first spacer, the first spacers are arranged side by side on one side of the second spacer. Fig. 12 is a partial enlarged view at B in Fig. 6. As shown in Figure 12, the light receiving sub-module includes four photoelectric conversion components. Furthermore, when the light receiving sub-module includes four first pads 5051, the four first pads 5051 are arranged side by side on one side of the second pad 304, and the first pads 5051 are arranged side by side on one side of the transimpedance amplifier 302. side. Each first pad 5051 is connected to the transimpedance amplifier 302 by wire bonding, so that the photodetector 5052 and the transimpedance amplifier 302 on each first pad 5051 are connected.

As shown in FIG. 12, a photodetector 5052 is respectively provided on the four first pads 5051, and the light receiving sub-module includes four photodetectors 5052. When the signal light received by the optical module is transmitted to the arrayed waveguide grating through the signal light of the optical fiber connector 503, and then split and transmitted to the inclined surface 5041 through the arrayed waveguide grating, the split signal light is reflected by the inclined surface 5041 to the corresponding photodetector 5052. Each photodetector 5052 receives the signal light and converts the signal light into a current signal, and then transmits it to the transimpedance amplifier 302 through the circuit of the corresponding first pad 5051.

FIG. 13 is a schematic diagram of a partial structure in still another optical module provided by an embodiment of the disclosure. As shown in FIG. 13, the optical module provided by the embodiment of the present disclosure further includes a cover plate 305. The cover plate 305 is fixed on the circuit board 300 and covered on the light receiving sub-module, and the cover plate 305 is used to protect the light receiving sub-module.

In the embodiment of the present disclosure, the cover plate 305 is arranged on the transimpedance amplifier. The periphery of the transimpedance amplifier is connected with the first pad, circuit board, etc. by wire bonding. However, the wire diameter of the gold wire is small and fragile, the wiring is dense, and the distance between the wires is narrow. During the packaging of the optical module or the use of the product , It is easy to deform, damage, collapse and other phenomena, which will affect the quality of the optical signal or cause short-circuit, open circuit and other defects. Therefore, the cover plate 305 is arranged on the transimpedance amplifier to protect the surrounding wiring of the transimpedance amplifier and the like.

In an embodiment of the present disclosure, the cover plate 305 is arranged on the circuit board 300, and the cover plate 305 arranged on the circuit board 300 forms a certain space with the circuit board 300, and the transimpedance amplifier and the transimpedance amplifier The wire wiring area is enclosed in the space formed by the cover plate 305 and the circuit board 300. It should be noted that the package in the embodiments of the present disclosure refers to the space formed by the cover plate 305 and the circuit board 300, where the transimpedance amplifier, the wiring and wiring area of the transimpedance amplifier, and other optoelectronic devices and the cover plate 305 achieve clearance fit. An assembly form.

At the same time, the cover plate 305 is also covered on the arrayed waveguide grating. Furthermore, the cover plate 305 can be used to protect the arrayed waveguide grating and effectively prevent the arrayed waveguide grating from being touched and caused to move.

In the optical module provided by the embodiment of the present disclosure, when the signal light transmitted to the photodetector is focused and transmitted to the photosensitive surface through the lens, the photosensitive surface converts the received signal light into a current signal and transmits it to the transimpedance amplifier. The received current signal is converted into a voltage signal and transmitted to the circuit board to complete the photoelectric conversion. Furthermore, the optical module provided by the embodiment of the present disclosure realizes the back-illuminated arrangement of the photodetector through the combination of the photodetector and the first spacer, and combines the lens formed on the back of the photodetector. The lens converges the signal light to the photosensitive surface, which is equivalent to adding The area of the photosensitive surface further reduces the coupling difficulty when the photodetector receives the optical signal, and improves the coupling efficiency of the signal light on the optical module.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, not to limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions recorded in the foregoing embodiments are modified, or some of the technical features are equivalently replaced; these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

An optical module, characterized in that it comprises:

Circuit board

The light receiving sub-module is electrically connected to the circuit board, and is used to convert the received signal light into a current signal;

The light receiving sub-module includes several photoelectric conversion components;

The photoelectric conversion component includes:

The first gasket is arranged on the circuit board, and a circuit is arranged on the front side;

The photodetector is provided with a photosensitive surface and an electrode on the front side, the front side is connected to the front side of the first pad and the electrode is connected to one end of the circuit, and the back side is away from the first pad and is formed with a surface for facing the photosensitive surface. A lens that converges the signal light to convert the received signal light into a current signal;

The optical module further includes:

The transimpedance amplifier is arranged on the circuit board and is connected with the other end of the circuit on the first pad to convert a current signal into a voltage signal and send it to the circuit board.
The optical module according to claim 1, wherein the optical module further comprises a second gasket, the bottom of the second gasket is connected to the circuit board, and the top of the second gasket supports the connection In the transimpedance amplifier, the second spacer is used to shorten the wire bonding length.
3. The optical module of claim 2, wherein the transimpedance amplifier is fixedly connected to the second pad through conductive silver glue, and the negative electrode of the transimpedance amplifier is grounded through the conductive silver glue.
The optical module according to claim 2, wherein the second shim heightens the transimpedance amplifier so that the circuit pins on the first shim are opposite to the pins of the transimpedance amplifier The heights are equal.
The optical module according to claim 1, wherein the light receiving sub-module further comprises an arrayed waveguide grating, and the arrayed waveguide grating is arranged on the photodetector;

One end of the arrayed waveguide grating receives signal light through an optical fiber connector, splits the signal light according to the wavelength of the signal light, and transmits each beam of signal light to a corresponding photodetector through the other end of the arrayed waveguide grating.
The optical module according to claim 5, wherein the other end of the arrayed waveguide grating is provided with an inclined surface, and the projection of the inclined surface in the direction of the circuit board covers the photosensitive surface of the photodetector.
The optical module according to claim 5, wherein the light receiving sub-module includes 4 photoelectric conversion components, and the arrayed waveguide grating will divide the signal light into 4 corresponding beams according to the wavelength of the received signal light. The transmission to the corresponding photodetector in the photoelectric conversion assembly.
The optical module according to claim 5, wherein the light receiving sub-module further comprises a third spacer, the third spacer is arranged on the circuit board and the third spacer is fixedly supported The arrayed waveguide grating.
The optical module of claim 2, wherein the second gasket is an aluminum nitride gasket.
The optical module according to claim 1, wherein the optical module further comprises a cover plate, and the cover plate is arranged on the light receiving sub-module.