WO2020088011A1

WO2020088011A1 - Receiver optical subassembly and optical module

Info

Publication number: WO2020088011A1
Application number: PCT/CN2019/098316
Authority: WO
Inventors: 刘鹏飞; 刘维伟; 傅钦豪
Original assignee: 青岛海信宽带多媒体技术有限公司
Priority date: 2018-11-02
Filing date: 2019-07-30
Publication date: 2020-05-07

Abstract

A receiver optical subassembly and an optical module. The receiver optical subassembly comprises: a metal shell (3); a circuit board (1) having a first end extending inside the metal shell (3) and a metal layer (6) formed in the first end; a metal cushion block (7) located below the circuit board (1) and formed with a metal boss (8); an optical receiver chip (5) located above the metal boss (8); an optical transmission array (2) having a second end extending inside the metal shell (3), the second end being opposite to the optical receiver chip (5); an optical receiver driving chip (4) located above the first end of the circuit board (1) and electrically connected to the optical receiver chip (5) and the metal layer (6); and a thermal insulating cushion block (9) located below the circuit board (1) and configured to achieve electric isolation between the optical receiver driving chip (4) and the metal shell (3).

Description

Optical receiving submodule and optical module

Cross-reference of related applications

This patent application requires the priority of the Chinese patent application filed on November 02, 2018 with application number 201811302373.9 and filed on November 02, 2018 with application number 201811301119.7, the entire content of which is incorporated by reference In this article.

Technical field

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

Background technique

The optical module is an important device to realize the photoelectric conversion in the optical fiber communication system, which includes a light emitting submodule (Transmitter Optical Subassembly, TOSA) and a light receiving submodule (Receiver Optical Subassembly, ROSA). Generally, the optical transmitting sub-module converts the electrical signal into an optical signal through a laser, and the optical signal is transmitted through the optical fiber; the optical receiving sub-module receives the optical signal transmitted from the optical fiber and converts the optical signal into an electrical signal, thereby realizing the photoelectricity of the optical module Conversion function.

Summary of the invention

The present disclosure provides an optical receiving sub-module and an optical module to improve the electrical isolation effect of the optical receiving sub-module on the optical receiving driving chip.

In a first aspect, an embodiment of the present disclosure provides an optical receiving sub-module, including:

Metal casing (3);

Circuit board (1) with:

Extending into the first end of the interior of the metal casing (3),

A metal layer (6) formed in the first end;

A metal pad (7), which is located below the circuit board (1), and is formed with a metal boss (8);

The light receiving chip (5) is located above the metal boss (8);

The light transmission array (2) has a second end extending into the metal casing (3), and the second end is opposite to the light receiving chip (5);

A light-receiving drive chip (4) located above the first end of the circuit board (1) and electrically connected to the light-receiving chip (5) and the metal layer (6); and

An insulating and thermally conductive pad (9) is located below the circuit board (1) and is used to achieve electrical isolation between the light-receiving drive chip (4) and the metal casing (3).

In a second aspect, an embodiment of the present disclosure provides an optical module, including: an upper casing and a lower casing, and a cavity formed by the upper casing and the lower casing is provided with a separately encapsulated light receiving submodule, Wherein, the optical receiving sub-module includes:

Metal casing (3);

Circuit board (1) with:

Extending into the first end of the interior of the metal casing (3),

A metal layer (6) formed in the first end;

The light receiving chip (5) is located above the metal boss (8);

It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and do not limit the present disclosure.

BRIEF DESCRIPTION

In order to more clearly explain the technical solutions of the present disclosure, the following will briefly introduce the drawings required in the embodiments. Obviously, for those of ordinary skill in the art, on the premise of not paying creative labor, Other drawings can be obtained from these drawings.

1 is a schematic structural view of an optical receiving sub-module according to an embodiment of the present disclosure;

2 is a partial cross-sectional view of the light receiving sub-module shown in FIG. 1 according to an embodiment of the present disclosure;

3 is a schematic diagram of an enlarged structure at A in FIG. 2 according to an embodiment of the present disclosure;

4 is a schematic diagram of an enlarged structure at B in FIG. 2 according to an embodiment of the present disclosure;

FIG. 5 is a schematic structural view of an insulating and thermally conductive pad to isolate a metal pad and a metal shell according to an embodiment of the present disclosure;

6 is a schematic structural view of an optical receiving sub-module according to another embodiment of the present disclosure;

7 is a partial cross-sectional view of the light receiving sub-module shown in FIG. 6 according to an embodiment of the present disclosure;

8 is a schematic diagram of an enlarged structure at A in FIG. 7 according to an embodiment of the present disclosure;

9 is a schematic structural view of an optical receiving sub-module according to yet another embodiment of the present disclosure;

10 is a schematic diagram of an internal structure of an optical module according to an embodiment of the present disclosure;

11 is a schematic structural diagram of a housing of an optical module according to an embodiment of the present disclosure.

detailed description

In order to realize the transmission of high-speed signals in the light-receiving sub-module, a light-receiving drive chip such as a trans-impedance amplifier (TIA, Trans-Impedance Amplifier) is usually placed in the package housing of the light-receiving sub-module. In this case, it is necessary to provide a suitable electrical isolation scheme for the light-receiving drive chip.

In order to improve the electrical isolation effect on the light-receiving drive chip, the embodiments of the present disclosure provide an improved light-receiving sub-module and an optical module having the improved light-receiving sub-module. In an embodiment, the light-receiving submodule includes a metal casing, a circuit board extending into the metal casing, and an optical transmission array. The circuit board has a first end extending into the interior of the metal housing and a metal layer formed in the first end. The light receiving sub-module further includes a light receiving chip, a light receiving driving chip and a metal pad. The metal pad is located under the circuit board and is formed with a metal boss. The light receiving chip is located above the metal boss. The light receiving driving chip is located above the first end of the circuit board and is electrically connected to the light receiving chip and the metal layer. The light-receiving chip and the light-receiving drive chip may be connected by wire bonding, for example. The light-receiving sub-module further includes a light-transmitting array. The light-transmitting array has a second end extending into the metal housing, and the second end is opposite to the light-receiving chip. The second end has a reflective slope to transmit the optical signal into the light receiving chip. The optical sub-module also includes an insulating thermal pad under the circuit board, which is used to achieve electrical isolation between the light-receiving drive chip and the metal housing.

The optical receiving sub-module and the optical module provided by the embodiments of the present application will be described in detail in the following with specific embodiments and drawings.

FIG. 1 shows a schematic structural view of an optical receiving sub-module according to an embodiment of the present application, and FIG. 2 shows a partial cross-sectional view of the optical receiving sub-module shown in FIG. 1 according to an embodiment of the present disclosure. As shown in FIGS. 1 and 2, the light receiving submodule includes a metal housing 3, a circuit board extending into the metal housing 3, an optical transmission array 2 extending into the metal housing 3, and light receiving inside the metal housing 3 The driving chip 4 is located in the light-receiving chip 5 inside the metal casing 3 and the insulating heat-conducting pad 9 located under the circuit board 1. The circuit board 1 is a carrier of components such as a light-receiving drive chip 4, and in an embodiment, the circuit board 1 is made of a flexible material, that is, the circuit board 1 may be a flexible circuit board. The end of the circuit board 1 that protrudes into the inside of the metal casing 3 is also referred to as a first end in the following. The optical transmission array 2 is a component that transmits optical signals, and is used to couple the transmitted optical signals into the optical receiving chip 5. In the embodiments of the present disclosure, the optical transmission array 2 may use components such as optical fiber arrays or arrayed waveguide gratings that can realize optical signal transmission. The metal case 3 is a component that encapsulates the light-receiving submodule. The light-receiving chip 5 is used to receive the light signal transmitted by the light-transmitting array 2, convert the light signal into an electrical signal, and transmit it to the light-receiving drive chip 4. In the embodiment of the present disclosure, the light receiving chip 5 includes an avalanche photodiode. The light-receiving drive chip 4 is used to receive the electrical signal transmitted by the light-receiving chip 5, and amplify the electrical signal for analysis processing. In the embodiment of the present disclosure, the light receiving driving chip 4 may use a transimpedance amplifier, a limiting amplifier, a fiber Raman amplifier, a semiconductor optical amplifier, or the like.

In one embodiment, the end (hereinafter also referred to as the second end) of the optical transmission array 2 extending into the metal casing 3 has a reflective slope, and the optical signal transmitted by the optical transmission array 2 is reflected by the reflective slope and then transmitted Into the light receiving chip 5. In an embodiment of the present disclosure, the inclination angle of the reflective slope may be, for example, 45 ± 5 °. The opposite side wall or the adjacent side wall of the metal housing 3 is provided with an opening, whereby the first end of the circuit board 1 extends into the interior of the metal housing 3 through the opening provided on the first side wall of the metal housing 3 The second end of the transmission array 2 extends into the interior of the metal casing 3 through the opening provided on the second side wall of the metal casing 3, thereby facilitating the package of the light receiving submodule on the printed circuit board of the optical module separately through the metal casing 3 on. The first side wall and the second side wall are adjacent or opposite. In an embodiment, in order to facilitate the arrangement of other components in the light-receiving submodule, the circuit board 1 and the light transmission array 2 both extend into the interior of the metal housing 3 through the openings provided in the middle of the opposite side walls of the metal housing 3. The light-receiving drive chip 4 and the light-receiving chip 5 are connected by wire bonding to realize signal transmission between the light-receiving drive chip 4 and the light-receiving chip 5. Since the shorter the wire bonding, the higher the signal transmission speed and quality, so the shorter the wire bonding between the light receiving drive chip 4 and the light receiving chip 5 is, the better. In order to achieve short-distance wire connection between the light-receiving drive chip 4 and the light-receiving chip 5, the circuit board 1 extends into the interior of the metal casing 3, thereby facilitating the packaging of the light-receiving submodule on the printed circuit board of the light module .

In the embodiment shown in FIGS. 1 to 5 of the present disclosure, the circuit board 1 has a metal layer 6 formed in the first end, the light-receiving drive chip 4 is disposed above the first end of the circuit board 1, and the metal pad 7 is disposed below the first end of the circuit board 1, and the metal layer 6 is in contact with the light-receiving drive chip 4 and the metal pad 7 respectively, as shown in FIG. 3.

In an embodiment, the first surface of the first end of the circuit board 1 is provided with a first metal region 13, the lower surface of the first end of the circuit board 1 is provided with a second metal region 14, and the first metal region 13 It is connected to the second metal region 14 through a via formed in the circuit board 1, thereby forming the metal layer 6 through the first metal region 13 and the second metal region 14 and the via, thereby realizing the light receiving driving chip 4 and the connection between the metal pad 7. In addition, the ground pin of the light-receiving drive chip 4 is connected to the metal layer 6, so that the light-receiving drive chip 4 is grounded. When the light-receiving drive chip 4 works, the light-receiving drive chip 4 generates heat. Since the metal layer 6 is in contact with the light-receiving drive chip 4 and the metal pad 7 respectively, the heat generated by the light-receiving drive chip 4 can be conducted to the metal pad 7 through the metal layer 6 to realize the light-receiving drive chip 4 Heat dissipation. In addition, since the metal pad 7 is located under the metal layer 6, the electrical properties of the ground of the metal layer 6 can be extended to the metal pad 7, so that the area of the ground in the light-receiving submodule is increased, which is beneficial to improve the signal transmission quality.

When the light receiving driving chip 4 works, the generated heat may deform the circuit board 1. Therefore, the metal pad 7 provided under the circuit board 1 can also prevent the circuit board 1 from deforming and supporting the circuit board 1. Since the heat generated by the light-receiving driving chip 4 is conducted to the metal pad 7 through the metal layer 6 and the metal layer 6 is located in the circuit board 1, the circuit board 1 located around the metal layer 6 is easily deformed by heat. In order to extend the service life of the circuit board 1, it is necessary to accelerate the heat conduction speed. To this end, a thermally conductive silver paste may be coated between the circuit board 1 and the metal pad 7 in the embodiments of the present disclosure.

In order to facilitate the optical transmission array 2 to transmit the optical signal to the optical receiving chip 5, the distance between the second end of the optical transmission array 2 and the optical receiving chip 5 is relatively fixed, and the distance is relatively short. Since the second end of the light transmission array 2 extends into the interior of the metal casing 3 through the opening provided on the second side wall of the metal casing 3, the position of the light transmission array 2 is relatively fixed. In order to achieve a relatively fixed distance between the second end of the light transmission array 2 and the light receiving chip 5, the position of the light receiving chip 5 also needs to be relatively fixed.

In order to achieve a relatively fixed position of the light-receiving chip 5, the embodiment of the present disclosure achieves a relatively fixed position of the light-receiving chip 5 by setting the metal pad 7 to a special shape. Specifically, the metal pad 7 is provided with a metal boss 8, and the metal boss 8 is provided with a light-receiving chip 5, thereby relatively fixing the position of the light-receiving chip 5. The arrangement of the metal boss 8 can also realize the height of the position of the light receiving chip 5, thereby facilitating the relatively fixed distance between the second end of the light transmission array 2 and the light receiving chip 5. The protrusion height of the metal boss 8 relative to the metal pad 7 can be set according to actual conditions. During actual preparation, the metal pad 7 and the metal boss 8 may be an integrally formed structure, that is, a complete metal block is molded into the structure of the metal pad 7 and the metal boss 8.

Further, an insulating layer 10 is provided between the metal boss 8 and the light receiving chip 5, as shown in FIG. A ground layer (not shown in the figure) is provided on the insulating layer 10. The ground pin of the light receiving chip 5 is connected to the ground layer on the insulating layer 10, whereby the light receiving chip 5 can be grounded.

Since the metal layer 6 in the circuit board 1 is in contact with the light-receiving drive chip 4 and the metal pad 7 respectively, and the thermally conductive silver paste coated between the circuit board 1 and the metal pad 7 has conductivity, the light-receiving drive chip 4 and the metal pad 7 can realize electrical transmission. In this case, if the metal pad 7 is directly located on the bottom surface of the metal casing 3, electrical transmission will be realized between the light-receiving drive chip 4, the metal layer 6, the metal pad 7 and the metal casing 3, which is not satisfactory The light receiving sub-module requires electromagnetic isolation of the light receiving drive chip.

In the optical module, the commonly used pad material is metal or ceramic. The ceramic has insulating and thermal conductivity characteristics, but the hardness is high, and it is difficult to make a boss or a depression. It is generally made into a pad with a flat surface; metal has electrical conductivity and thermal conductivity. It has strong plasticity and can be made into various shapes. Therefore, in the embodiment of the present disclosure, the material of the block provided under the circuit board 1 is metal. In addition, in order to meet the electromagnetic isolation requirements for the light-receiving drive chip 4 in the light-receiving submodule, an electrical isolation structure needs to be provided. In the embodiment of the present disclosure, when designing the light-receiving sub-module, in order to provide pads for the circuit board 1, different electrical isolation structures are designed according to different characteristics of metals and ceramics.

In an embodiment, an insulating and thermally conductive pad 9 is provided between the bottom surface of the metal shell 3 and the metal pad 7, and the insulating and thermal pad 9 can achieve isolation between the metal shell 3 and the metal pad 7, as shown in FIG. 1 And 2. In the embodiment of the present disclosure, the insulating and thermal pad 9 is made of ceramic material. Since the bottom of the metal shell 3 and the metal pad 7 are provided with an insulating and thermally conductive pad 9, and the insulating and thermally conductive pad 9 can isolate the metal shell 3 and the metal pad 7, the metal shell 3 and the metal pad 7 will not Electric transmission occurs, and the light receiving driving chip 4 provided above the circuit board 1 and electrically connected to the metal pad 7 and the metal housing 3 do not undergo electric transmission, thereby allowing the light receiving sub-module to have good light alignment Receive the electrical isolation effect of the driving chip 4.

The embodiment of the present disclosure provides a way of insulating the thermal conductive pad 9 to isolate the metal pad 7 and the metal shell 3, but this is only an exemplary way and does not limit the insulating thermal conductive pad 9 to isolate the metal pad 7 from the metal in this disclosure Other ways of housing 3.

FIG. 5 shows a structural schematic view of the insulating and thermally conductive pad 9 separating the metal pad 7 and the metal shell 3 according to an embodiment of the present disclosure. As shown in FIG. 5, the insulating and thermal pad 9 is located on the inner bottom surface of the metal shell 3, and the metal pad 7 is located on the insulating and thermal pad 9. Thus, the metal pad 7, the insulating thermal pad 9 and the bottom surface of the metal shell 3 Presented as a stack up and down. Since the bottom surfaces of the metal pad 7, the insulating and thermally conductive pad 9 and the metal shell 3 are stacked up and down, the metal pad 7 and the insulating and thermally conductive pad 9 can be projected on the bottom surface of the metal shell 3 respectively. If the projection of the insulating and thermally conductive pad 9 on the bottom surface of the metal shell 3 includes the projection of the metal pad 7 on the bottom of the metal shell 3, it means that the size of the metal pad 7 is smaller than the size of the insulating and thermal pad 9 The block 7 is not in contact with the side wall of the metal shell 3, thereby the insulating and thermally conductive pad 9 can also be used to isolate the metal pad 7 from the metal shell 3.

Since the first end of the circuit board 1 and the second end of the light transmission array 2 enter the interior of the metal housing 3 through the opening provided on the side wall of the metal housing 3, the junction of the circuit board 1 and the metal housing 3 and / or The joint between the light transmission array 2 and the metal casing 3 is adhered by applying a sealant, thereby achieving the sealing of the metal casing 3. Of course, the sealing of the metal shell 3 can also be achieved in other ways.

In an embodiment, after the light receiving chip 5 is fixed on the metal boss 8, an insulating and thermally conductive pad 9 and a metal pad 7 are placed in sequence on the bottom inside the metal casing 3. The first end of the circuit board 1 provided with the metal layer 6 and the light-receiving drive chip 4 extends into the inside of the metal case 3, and at the same time, the second end of the light transmission array 2 extends into the inside of the metal case 3, And adjust the distance between the second end of the light transmission array 2 and the light receiving chip 5. After the distance between the second end of the light transmission array 2 and the light receiving chip 5 is adjusted, the moisture carried on each component is removed by baking. After the water vapor is removed, sealant is applied to the junction of the circuit board 1 and the metal casing 3 and / or the junction of the light transmission array 2 and the metal casing 3. After the sealant is cured, the metal shell 3 is sealed. If there are other parts of the metal shell 3 that are not sealed, the whole sealing of the metal shell 3 is achieved by filling the sealant. In the embodiment of the present disclosure, the sealing of the metal shell 3 is realized by a shadowless glue with waterproof performance.

Furthermore, in order to fully ensure a moisture-free working environment for the components inside the metal casing 3, the metal casing 3 may also be filled with nitrogen to further reduce the water vapor inside the metal casing 3.

In the light-receiving sub-module according to the embodiment of the present disclosure, the outer surface of the metal housing 3 is also provided with a fixing post 12. The fixing column 12 is used to fix the metal shell 3 on the printed circuit board of the optical module, and then realize the fixing of the light receiving sub-module on the printed circuit board of the optical module. Since the fixing post 12 is used to fix the metal casing 3 on the printed circuit board of the optical module, the position of the fixing post 12 and the size of the fixing post 12 need to be set according to actual conditions.

FIGS. 1-5 provide a light receiving submodule in which the first end of the circuit board 1 extends into the interior of the metal housing 3 through the opening in the first side wall of the metal housing 3, The second end of the light transmission array 2 extends into the interior of the metal casing 3 through the opening in the second side wall of the metal casing 3, so that the light receiving driving chip 4 on the circuit board 1 and the light receiving chip inside the metal casing 3 5 Close-range connection is conducive to improving the signal transmission quality. A metal layer 6 is formed in the circuit board 1, a light-receiving drive chip 4 is provided above the metal layer 6, and a metal pad 7 is provided below the metal layer 6. The metal layer 6 can be in contact with the light-receiving drive chip 4 and the metal pad 7 respectively, so that the light-receiving drive chip 4 can achieve grounding and heat dissipation through the metal layer 6. The metal pad 7 is formed with a metal boss 8, the light receiving chip 5 is disposed above the metal boss 8, the second end of the light transmission array 2 has a reflective slope, and the reflection slope is used to transmit the optical signal to the light receiving chip 5 in. An insulating and thermally conductive pad 9 is provided between the bottom surface of the metal shell 3 and the metal pad 7, and the insulating and thermal pad 9 electrically isolates the metal shell 3 and the metal pad, thereby making the light receiving submodule have good light reception The electrical isolation effect of the driving chip 4.

FIG. 6 shows a schematic structural view of a light receiving sub-module according to another embodiment of the present disclosure, and FIG. 7 shows a partial cross-sectional view of the light receiving sub-module shown in FIG. 6. It can be seen from FIGS. 6 and 7 that the light-receiving sub-module includes a metal housing 3, and both the first end of the circuit board 1 and the second end of the light transmission array 2 can extend into the metal housing 3, thereby facilitating passage through the metal housing 3 Package the light receiving sub-module separately on the printed circuit board of the optical module.

For the light transmission array 2 whose second end extends into the interior of the metal casing 3, the second end of the light transmission array 2 has a reflective slope, which is used to reflect and transmit the optical signal to the light receiving chip 5. For the setting of the optical transmission array 2, please refer to FIGS. 1-2, which will not be repeated here.

For the circuit board 1 whose first end extends into the metal casing 3, a metal layer 6 is provided in the circuit board 1, a light-receiving drive chip 4 is provided above the circuit board 1, and a metal pad block is provided below the circuit board 1 7, and the metal layer 6 is in contact with the light-receiving drive chip 4, as shown in FIG. In addition, the ground pin of the light-receiving drive chip 4 is connected to the metal layer 6, so that the light-receiving drive chip 4 is grounded.

In the light-receiving sub-module shown in FIGS. 6 to 7, the metal pad 7 is provided with a metal boss 8. A light receiving chip 5 is provided on the metal boss 8, and the light receiving driving chip 4 and the light receiving chip 5 are connected by wire bonding. For the arrangement between the light-receiving chip 5, the metal pad 7 and the metal boss 8, please refer to FIGS. 1-5, which will not be repeated here.

A metal layer 6 is provided in the circuit board 1, and a metal pad 7 is provided under the circuit board 1. The metal pad 7 may be located on the bottom surface of the metal shell 3. When the metal pad 7 is located on the bottom surface of the metal shell 3, and the metal layer 6 is in contact with the metal pad 7, the light-receiving drive chip 4, the metal layer 6, the metal pad 7 and the metal shell electrically connected to the metal layer 6 The electrical transmission can be realized between 3, which does not meet the electromagnetic isolation requirements of the light receiving sub-module on the light receiving drive chip.

Based on this, in the light-receiving sub-module shown in FIGS. 6 to 7, an insulating and thermally conductive pad 9 is further provided between the first end of the circuit board 1 and the metal pad 7, as shown in FIGS. 7 and 8. Since the insulating and thermally conductive pad 9 isolates the circuit board 1 and the metal pad 7, no electrical transmission occurs between the metal layer 6 and the metal pad 7 formed in the circuit board 1, which is further provided on the circuit board 1 and is separated from the metal No electrical transmission occurs between the light-receiving drive chip 4 and the metal pad 7 electrically connected to the layer 6, thereby making the light-receiving sub-module have a good electrical isolation effect on the light-receiving drive chip 4.

Since the volume of the light-receiving drive chip 4 is small, and the metal layer 6 below the light-receiving drive chip 4 can realize heat dissipation and grounding of the light-receiving drive chip 4, the volume of the metal layer 6 is generally small. When the volume of the metal layer 6 is small, it is not conducive to the heat dissipation and grounding of the light-receiving drive chip 4. For this reason, the metal pad 11 may be provided on the insulating and thermally conductive pad 9 and the metal pad 11 is in contact with the metal layer , As shown in Figure 8. Since the area of the insulating and thermally conductive pad 9 is large, the metal pad 11 with a large area can be provided. When the area of the metal pad 11 is large, since the light receiving drive chip 4 dissipates heat and grounds through the metal layer 6, and the metal pad 11 contacts the metal layer 6, the ground area of the light receiving drive chip 4 can be increased, At the same time, the heat conduction on the metal layer 6 can be accelerated.

9 is a schematic structural diagram of an optical receiving sub-module according to yet another embodiment of the present application. In the embodiment shown in FIG. 9, the light receiving chip 5 is an avalanche photodiode as an example. The voltage provided by the host computer or system end to the optical module is 3.3V, and the voltage required for the operation of the avalanche photodiode is 30V-60V, so a booster circuit needs to be provided on the circuit board 1. In the booster circuit, the capacitor is a key device. Due to its large capacitance, it is not suitable for being placed on the circuit board 1. Therefore, a recessed area is provided on the surface of the metal pad 7, the capacitor 15 is placed on the recessed area A part of the booster circuit is connected to the booster circuit in the circuit board 1, that is, a part of the circuit in the booster circuit in the circuit board 1 and the capacitor 15 together form a complete booster circuit. The structure of the booster circuit in the optical module well known to those skilled in the art may be used, and details are not described herein again.

As shown in FIG. 9, the capacitor 15 is located below the light transmission array 2. In order to avoid the position of the light transmission array 2, the metal pad 7 is formed with a recessed area, and the height of the recessed area is lower than the height of the metal pad 7. In order to avoid the light transmission array 2, the recessed area can be set to any shape / structure. During actual preparation, the metal pad 7, the recessed area and the metal boss 8 may be an integrally formed structure.

For other components shown in the embodiment shown in FIG. 9, reference may be made to the foregoing FIGS. 1 to 8, and details are not described herein again.

10 shows a schematic diagram of an internal structure of an optical module according to an embodiment of the present disclosure, and FIG. 11 shows a schematic diagram of a structure of a housing of the optical module according to an embodiment of the present disclosure. As can be seen from FIGS. 10 and 11, the optical module according to the embodiment of the present disclosure includes an upper case 110, a lower case 120, a light-emitting sub-module 130 and a light-receiving sub-module 140. The light-emitting sub-module 130 and the light-receiving sub-module 140 are located in the cavity formed by the upper casing and the lower casing. The optical receiving sub-module 140 realizes the transmission of optical signals through the optical transmission array 2 described in FIGS. 1 to 8. In the embodiment of the present disclosure, the light receiving sub-module 140 selects the light receiving sub-module in the above embodiment.

In the embodiment of the present disclosure, the light transmitting sub-module 130 and the light receiving sub-module 140 are separately packaged on the printed circuit board 160 of the optical module. In order to prevent the optical transmitting sub-module 130 and the optical receiving sub-module 140 from generating electromagnetic crosstalk and thermal crosstalk due to the short distance, the optical transmitting sub-module 130 and the optical receiving sub-module 140 in the embodiments of the present disclosure are separately packaged in the printed circuit of the optical module The different positions of the board 160 are the front and rear positions as shown in FIG. In addition, the optical module according to the embodiment of the present disclosure further includes an optical fiber connector 150. The optical fiber connector 150 is a component that connects the optical transmission array 2 and further realizes the detachable connection of the optical fiber.

After considering the description and practicing the embodiments disclosed herein, those skilled in the art will easily think of other embodiments of the present disclosure. This disclosure is intended to cover any variations, uses, or adaptive changes of this disclosure that follow the general principles of this disclosure and include common general knowledge or customary technical means in the technical field not disclosed in this disclosure . The description and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are pointed out by the following claims.

It should be understood that relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations There is any such actual relationship or order. The present disclosure is not limited to the precise structure that has been described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

An optical receiving sub-module, including:

metal shell;

Circuit board with:

Extending into the first end of the metal shell,

A metal layer formed in the first end;

A metal pad, located under the circuit board, and formed with a metal boss;

The light receiving chip is located above the metal boss;

The light transmission array has a second end extending into the metal casing, and the second end is opposite to the light receiving chip;

A light-receiving drive chip located above the first end of the circuit board and electrically connected to the light-receiving chip and the metal layer; and

An insulating and thermally conductive pad is located below the circuit board, and is used to achieve electrical isolation between the light receiving driving chip and the metal casing.
The light receiving sub-module according to claim 1, wherein

The insulating and thermally conductive pad is interposed between the bottom surface of the metal shell and the metal pad; and

The projection of the metal pad on the bottom surface of the metal shell does not exceed the projection of the insulated thermal pad on the bottom surface of the metal shell.
The light receiving sub-module according to claim 2, wherein:

A thermally conductive silver glue is coated between the first end of the circuit board and the metal pad.
The light receiving sub-module according to claim 1, wherein

The insulating and thermally conductive pad is sandwiched between the first end of the circuit board and the metal pad, so that the metal layer is electrically isolated from the metal pad.
The light receiving sub-module according to claim 4, wherein:

A metal gasket is also interposed between the insulating and thermally conductive pad block and the first end of the circuit board;

The metal gasket is in contact with the metal layer;

The projection of the metal gasket on the circuit board is greater than the projection of the metal layer on the circuit board.
The light receiving sub-module according to any one of claims 1 to 5, wherein,

A first metal area is formed on the upper surface of the first end of the circuit board;

A second metal area is formed on the lower surface of the first end of the circuit board;

The first metal region and the second metal region are connected by vias;

The first metal region, the second metal region, and the via form the metal layer.
The light receiving sub-module according to any one of claims 1 to 6, wherein,

The second end of the light transmission array has a reflective slope to transmit the optical signal to the light receiving chip.
The light receiving sub-module according to any one of claims 1 to 7, wherein

The ground pin of the light receiving driving chip is connected to the metal layer.
The light receiving sub-module according to any one of claims 1 to 7, wherein

An insulating layer is interposed between the metal boss and the light receiving chip;

The ground pin of the light receiving chip is connected to the ground layer in the insulating layer.
The light receiving sub-module according to any one of claims 1 to 9, wherein

The first end of the circuit board extends into the interior of the metal housing through an opening provided on the first side wall of the metal housing;

The second end of the light transmission array extends into the interior of the metal housing through an opening provided on the second side wall of the metal housing;

The first side wall is adjacent to or opposite to the second side wall.
The light receiving sub-module according to any one of claims 1 to 10, wherein

The junction of the circuit board and the metal casing is coated with sealant; and / or

The joint of the light transmission array and the metal casing is coated with sealant.
The light-receiving submodule according to any one of claims 1 to 11, wherein the light-receiving chip includes an avalanche photodiode.
The light receiving sub-module according to claim 2, wherein the circuit board includes a booster circuit connected to the light receiving chip.
The optical receiving sub-module according to claim 13, wherein

The metal pad includes a recessed area,

The boost circuit includes a capacitor provided on the recessed area,

The output end of the booster circuit is connected to the power supply end of the light receiving chip,

The light receiving driving chip is connected to the output end of the light receiving chip.
An optical module, including:

Upper shell

Lower shell

The cavity formed by the upper case and the lower case is provided with the light-receiving sub-module according to any one of claims 1-14, which is individually encapsulated.