CN113325526A

CN113325526A - Optical module

Info

Publication number: CN113325526A
Application number: CN202110578417.6A
Authority: CN
Inventors: 张加傲; 王欣南; 慕建伟
Original assignee: Hisense Broadband Multimedia Technology Co Ltd
Current assignee: Hisense Broadband Multimedia Technology Co Ltd
Priority date: 2021-05-26
Filing date: 2021-05-26
Publication date: 2021-08-31

Abstract

The optical module comprises a circuit board, a light emission secondary module and a flexible circuit board, wherein the light emission secondary module comprises a shell and a ceramic switching block plated with a metal layer, one side of the ceramic switching block is inserted into the shell, and the other side of the ceramic switching block is exposed out of the shell; signal pads and grounding pads are arranged on the metal layer of the ceramic switching block, and the signal pads inside and outside the ceramic switching block are connected; an isolation groove is arranged between the signal pad and the grounding pad on the outer side of the shell on the ceramic switching block, and the isolation groove is recessed in the signal pad and the grounding pad; one end of the flexible circuit board is connected with the ceramic switching block, and the other end of the flexible circuit board is connected with the circuit board. This application exposes on ceramic switching piece and sets up the isolation groove between the signal pad in the casing outside and the ground connection pad, and the isolation groove is sunken in the signal pad, has reduced ceramic switching piece's dielectric constant through the isolation groove, has reduced the impedance discontinuity of flexible circuit board and ceramic switching piece junction to improve signal transmission quality, guaranteed signal integrality.

Description

Optical module

Technical Field

The application relates to the technical field of optical fiber 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.

Optical modules typically include a circuit board and an optical sub-assembly, which may or may not be hermetically sealed. In high-speed products, the optical sub-assemblies are usually packaged in a hermetic package, and the hermetic housing and the circuit board are connected through a flexible circuit board, so that the hermetic housing and the flexible circuit board are interconnected. The mode of a pad for interconnecting the airtight shell and the flexible circuit board is a GSG mode, the shell and the flexible circuit board are connected through soldering tin, and the width of the pad is ensured to be a certain size so as to be welded successfully. Therefore, impedance discontinuous points exist at the welding positions of the welding pads of the child shell and the welding pads of the flexible circuit board, so that signal quality is changed, and signal integrity is deteriorated.

Disclosure of Invention

The embodiment of the application provides an optical module to solve the problem that the signal integrity is poor due to impedance discontinuity at the welding position of a pad of an airtight shell of the existing optical module and a pad of a flexible circuit board.

The application provides an optical module, includes:

a circuit board;

the light emission secondary module comprises a shell and a ceramic adapter block plated with a metal layer, wherein an opening is formed in one side of the shell, one side of the ceramic adapter block is inserted into the shell through the opening, and the other side of the ceramic adapter block is exposed out of the shell; a signal pad and a grounding pad are arranged on the metal layer of the ceramic switching block side by side, and the signal pads inside and outside the ceramic switching block are connected; an isolation groove is arranged between the signal pad and the grounding pad on the ceramic switching block and positioned on the outer side of the shell, and the isolation groove is recessed in the signal pad and the grounding pad;

and one end of the flexible circuit board is connected with the ceramic switching block through the signal bonding pad and the grounding bonding pad, and the other end of the flexible circuit board is connected with the circuit board.

The optical module comprises a circuit board, a light emission submodule and a flexible circuit board, wherein the light emission submodule comprises a shell and a ceramic switching block plated with a metal layer, an opening is formed in one side of the shell, one side of the ceramic switching block is inserted into the shell through the opening, and the other side of the ceramic switching block is exposed out of the shell; the metal layer of the ceramic switching block is provided with a signal pad and a grounding pad side by side, and the signal pads inside and outside the ceramic switching block are connected to realize signal transmission inside and outside the ceramic switching block; an isolation groove is arranged between the signal pad and the grounding pad on the outer side of the shell on the ceramic switching block, and the isolation groove is recessed in the signal pad and the grounding pad; one end of the flexible circuit board is connected with the ceramic switching block through the signal bonding pad and the grounding bonding pad, and the other end of the flexible circuit board is connected with the circuit board. In the optical module that this application provided, the one end of pottery switching piece is inserted the casing and is constituteed airtight tube shell, and the other end exposes in the casing outside, and the pottery switching piece that exposes in the casing outside sets up the isolation groove through signal pad, ground connection pad and the direct welding of flexible circuit board on it, and lies in on the pottery switching piece between the signal pad and the ground connection pad of casing shell, and the isolation groove recess is in the signal pad. The electrical connection of the inner side and the outer side of the ceramic switching block is realized through the ceramic switching block plated with the metal layer, the inner side of the ceramic switching block is electrically connected with the light emitting component, the outer side of the ceramic switching block is electrically connected with the flexible circuit board, and the isolation groove is arranged on the side surface of the ceramic switching block connected with the flexible circuit board, so that the dielectric constant of the ceramic switching block can be reduced, and further the impedance discontinuity point at the connection part of the flexible circuit board and the ceramic switching block can be reduced, thereby improving the signal transmission quality and ensuring the integrity of signals; in addition, the isolation groove is arranged on the end face of the ceramic adapter block exposed outside the shell, and the airtight packaging of the transmitter optical subassembly is not affected.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

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

FIG. 2 is a schematic diagram of an optical network unit;

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

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

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

fig. 6 is an exploded schematic view of a light emission sub-module in an optical module according to an embodiment of the present disclosure;

fig. 7 is a schematic assembly diagram of a laser module, a ceramic transition block, and a flexible circuit board in an optical module according to an embodiment of the present disclosure;

fig. 8 is an assembly schematic diagram of a ceramic transition block and a flexible circuit board in an optical module according to an embodiment of the present disclosure;

fig. 9 is an exploded schematic view of a ceramic transition block and a flexible circuit board in an optical module according to an embodiment of the present disclosure;

fig. 10 is a schematic structural diagram of a ceramic transition block in an optical module according to an embodiment of the present disclosure;

fig. 11 is a schematic view of another angular structure of a ceramic transition block in an optical module according to an embodiment of the present disclosure;

fig. 12 is a schematic partial structure diagram of a ceramic transition block in an optical module according to an embodiment of the present application.

Detailed Description

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 of 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 information transmission with low cost and low loss can be realized by using the passive transmission characteristic of 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 of the optical module, and the main electrical connection comprises power supply, I2C signals, data signals, 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 accessed 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 interconversion 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 through 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.

At this point, a bidirectional signal transmission channel is established between the remote server and the local information processing device 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 has 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 an electric port of an optical module such as a golden finger; the cage 106 is provided with a heat sink 107, and the heat sink 107 has a projection such as a fin that increases a heat radiation area.

The optical module 200 is inserted into the optical network terminal, 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, held by the cage, and the 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 view of an optical module according to an embodiment of the present disclosure, and fig. 4 is a schematic view of an exploded structure of an optical module according to an embodiment of the present disclosure. 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, a tosa 400, and a tosa 500.

The upper shell 201 is covered on the lower shell 202 to form a wrapping cavity with two openings; the outer contour of the wrapping cavity is generally a square body, and specifically, the lower shell comprises a main plate and two side plates which are positioned at two sides of the main plate and are perpendicular to the main plate; the upper shell comprises a third shell, and the third shell covers the two side plates of the upper shell to form a wrapping cavity; the upper shell can also comprise two side walls which are positioned on two sides of the third shell and are perpendicular to the third shell, and the two side walls are combined with the two side plates to cover the upper shell on the lower shell.

The two openings may be two ends (204, 205) in the same direction, or two openings in different directions; 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 the optical transmitter sub-module 400 and the optical receiver sub-module 500 inside the optical module; the optoelectronic devices such as the circuit board 300, the transmitter sub-assembly 400, the receiver sub-assembly 500, etc. 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 transmitter sub-module 400, the receiver sub-module 500 and other devices can be conveniently installed in the shells, and the outermost packaging protection shell of the optical module is formed by the upper shell and the lower shell; the upper shell and the lower shell are made of metal materials generally, so that electromagnetic shielding and heat dissipation are facilitated; generally, the housing of the optical module is not made into an integrated component, so that when devices such as a circuit board and the like are assembled, the positioning component, the heat dissipation component and the electromagnetic shielding component cannot be installed, and the 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 component can be pulled to enable the unlocking component to move relatively 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 a clamping component of the unlocking component; by pulling the unlocking component, the clamping component of the unlocking component moves along with the unlocking component, so that the connection relation between the clamping component and the upper computer is changed, the clamping relation 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 connects the electrical appliances in the optical module together according to the circuit design through circuit wiring to realize the functions of power supply, electrical signal transmission, grounding and the like.

The chip on the circuit board 300 may be a multifunctional integrated chip, for example, a laser driver chip and an MCU chip are integrated into one chip, or a laser driver chip, a limiting amplifier chip and an MCU chip are integrated into one chip, and the chip is an integrated circuit, but the functions of the circuits do not disappear due to the integration, and only the circuit appears and changes, and the chip still has the circuit form. Therefore, when the circuit board is provided with three independent chips, namely, the MCU, the laser driver chip and the limiting amplifier chip, the scheme is equivalent to that when the circuit board 300 is provided with a single chip with three functions in one.

The circuit board is generally a hard circuit board, and the hard circuit board can also realize a bearing effect due to the relatively hard material of the hard circuit board, for example, the hard circuit board can stably bear a chip; when the optical transceiver 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/golden 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 device through the flexible circuit board.

In order to increase the transmission rate of the optical module and adapt to various severe environments, the tosa 400 and the rosa 500 of the optical module need to have air tightness, and therefore the tosa 400 and the rosa 500 usually adopt an air-tight shell package structure.

Fig. 5 is an assembly diagram of the tosa 400 and the flexible circuit board according to the embodiment of the present disclosure, and fig. 6 is an exploded diagram of the tosa 400 and the flexible circuit board according to the embodiment of the present disclosure. As shown in fig. 5 and 6, the tosa 400 according to the embodiment of the present invention includes a housing and a ceramic transition block 430, the housing includes a cover plate 410 and a package 420, the cover plate 410 covers the package 420; the side of the package 420 facing the circuit board 300 is provided with an opening through which one side of the ceramic junction block 430 is inserted into the package 420 and the other side is exposed outside the package 420, so that the cover plate 410, the package 420 and the ceramic junction block 430 are assembled to form an airtight housing.

The tosa 400 includes a laser assembly 440, a lens array 450, a wdm assembly and a lens assembly, the laser assembly 440, the lens array 450, the wdm assembly and the lens assembly are all disposed in an airtight housing formed by the cover plate 410, the tube housing 420 and the ceramic transition block 430, and the laser assembly 440, the lens array 450, the wdm assembly and the lens assembly are sequentially disposed along a light emitting direction. The laser component is used for emitting light beams with different wavelengths, the light beams with different wavelengths are combined through optical devices such as the lens array 450, the wavelength division multiplexing component and the lens component, and the combined light beams are transmitted to an external optical fiber through the optical fiber adapter so as to achieve emission of the light beams.

Specifically, the laser assembly 440 includes a plurality of lasers, each of which is disposed proximate to the ceramic transition block 430, and each of which is connected to the ceramic transition block 430 by a gold wire. The ceramic transfer block 430 is provided with a pad at one end of the airtight housing, and the laser is connected with the pad through a gold wire to electrically connect the laser assembly 440 with the ceramic transfer block 430 in the airtight housing.

In this embodiment, the laser assembly 440 includes 8 lasers, the 8 lasers are sequentially disposed along the front-back direction of the airtight housing, and the 8 lasers emit 8 laser beams with different wavelengths, the 8 laser beams with different wavelengths are combined by the optical devices such as the lens array 450, the wavelength division multiplexing assembly, and the lens assembly to obtain a combined beam, and the combined beam is transmitted to the external optical fiber through the optical fiber adapter.

The lens array 450 includes 8 collimating lenses, each collimating lens is disposed corresponding to each laser and located in the light emitting direction of the laser, so that the laser beam emitted by the laser is converted into a collimated beam by the collimating lens, and the collimated beam enters the wavelength division multiplexing assembly for light combination.

The wavelength division multiplexing assembly comprises a first wavelength division multiplexer 460 and a second wavelength division multiplexer 470, the first wavelength division multiplexer 460 is arranged corresponding to the 4 lasers and the 4 collimating lenses, and 4 laser beams with different wavelengths emitted by the 4 lasers are incident into the first wavelength division multiplexer 460 through the collimating lenses; the second wavelength division multiplexer 470 is disposed corresponding to the other 4 lasers and 4 collimating lenses, and 4 laser beams with different wavelengths emitted by the other 4 lasers are incident into the second wavelength division multiplexer 470 through the collimating lenses.

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

The lens components comprise a first lens component 480 and a second lens component 490, the first lens component 480 is arranged in the light-emitting direction of the first wavelength division multiplexer 460, the second lens component 490 is arranged in the light-emitting direction of the second wavelength division multiplexer 470, the first composite light beam emitted by the first wavelength division multiplexer 460 is reflected to the second lens component 490 through the first lens component 480, the second composite light beam emitted by the second wavelength division multiplexer 470 is emitted into the second lens component 490, the reflected first composite light beam and the second composite light beam are combined into a light beam through the second lens component 490, and the combined light beam is emitted out in the optical fiber adapter.

Fig. 7 is an assembly diagram of a laser assembly 440, a ceramic transition block 430, and a flexible circuit board in an optical module according to an embodiment of the present disclosure. As shown in fig. 7, one end of the ceramic transition block 430 located inside the hermetic shell is connected to each laser of the laser assembly 440 through a gold wire, one end of the ceramic transition block 430 located outside the hermetic shell is connected to the circuit board 300 through a flexible circuit board, and the electrical signal, the working signal, etc. generated by the circuit board 300 are transferred to each laser through the flexible circuit board and the ceramic transition block 430, so as to drive each laser to emit laser beams with different wavelengths.

In order to realize the electrical connection between the inside and the outside of the housing through the ceramic transfer block 430, a metal layer is plated on the ceramic transfer block 430, a signal pad and a ground pad are arranged on the metal layer of the ceramic transfer block 430 positioned on the inner side of the housing, a signal pad and a ground pad are also arranged on the metal layer of the ceramic transfer block 430 positioned on the outer side of the housing, and the signal pads on the inside and the outside of the ceramic transfer block 430 are connected to realize the electrical connection between the inside and the outside of the ceramic transfer block 430, so that the transfer of electrical signals, working signals and the like is realized through the ceramic transfer block 430.

Fig. 8 is an assembly schematic diagram of a ceramic transition block 430 and a flexible circuit board in an optical module according to an embodiment of the present disclosure, and fig. 9 is an exploded schematic diagram of the ceramic transition block 430 and the flexible circuit board in the optical module according to the embodiment of the present disclosure. The end of the ceramic transition block 430 facing the circuit board 300 (the end located outside the hermetic shell) is provided with a boss 4310, the boss 4310 and the ceramic transition block 430 are integrally arranged, the boss 4310 is connected with the flexible circuit board, the signal of the circuit board 300 is transmitted to the ceramic transition block 430 through the flexible circuit board, the ceramic transition block 430 transfers the signal to the laser assembly 440, and the normal operation of the laser, etc. in the laser assembly 440 is realized.

The ceramic transfer block 430 is provided with a plurality of mounting grooves 4320 at one side inserted into the hermetic case, the mounting grooves 4320 are arranged in a step shape, each mounting groove 4320 is provided with a bonding pad, and a laser driver, a laser and the like of the laser assembly 440 are respectively connected with the bonding pads on the mounting grooves 4320 through gold wires to realize signal transfer.

The boss 4310 on one side of the ceramic transition block 430 may be connected to the circuit board 300 through two flexible circuit boards, that is, the upper side of the boss 4310 is connected to the first flexible circuit board 600, and the lower side of the boss 4310 is connected to the second flexible circuit board 700, so as to transmit various signals.

In order to realize the connection between the ceramic transfer block 430 and the flexible circuit board, a signal pad and a ground pad are arranged side by side on the side surface of the boss 4310, an FPC signal pad and an FPC ground pad are correspondingly arranged at one end of the flexible circuit board, the signal pad on the ceramic transfer block 430 is connected with the corresponding FPC signal pad on the flexible circuit board through soldering tin, and the ground pad on the ceramic transfer block 430 is connected with the corresponding PC ground pad on the flexible circuit board through soldering tin, so that the connection and fixation between the flexible circuit board and the ceramic transfer block 430 are realized.

In the embodiment of the present application, the length dimension of the front-back direction of the boss 4310 is the same as the length dimension of the front-back direction of the ceramic transfer block 430, so that a sufficient space is left on the side surface of the boss 4310 to dispose the signal pad and the ground pad, thereby ensuring the integrity of signal transmission between the ceramic transfer block 430 and the flexible circuit board. Furthermore, the upper side of the boss 4310 is spaced from the upper side of the ceramic transfer block 430 by a certain distance, and the lower side of the boss 4310 is also spaced from the lower side of the ceramic transfer block 430 by a certain distance, so as to facilitate the welding of the upper and lower sides of the boss 4310 with the flexible circuit board.

Fig. 10 is a schematic structural diagram of a ceramic transition block 430 in an optical module according to an embodiment of the present disclosure, fig. 11 is another schematic structural diagram of an angle of the ceramic transition block 430 in the optical module according to the embodiment of the present disclosure, and fig. 12 is a schematic partial structural diagram of the ceramic transition block 430 in the optical module according to the embodiment of the present disclosure. As shown in fig. 10, 11 and 12, in the high-speed product, the transmission mode of the high-speed Signal is GND-Signal-GND mode, and thus the pad mode of the interconnection between the ceramic transfer block 430 and the flexible circuit board is GSG mode, that is, the Signal pad and the ground pad disposed on the side of the boss 4310 of the ceramic transfer block 430 are configured as a first ground pad 4311, a Signal pad 4312 and a second ground pad 4313, and the Signal pad 4312 is disposed between the first ground pad 4311 and the second ground pad 4313.

When the first ground pad 4311, the signal pad 4312 and the second ground pad 4313 on the pad 4310 are connected to the pad on the flexible circuit board, the pads need to be connected by soldering tin, and the width of the pads needs to be ensured to be a certain size, so that the first ground pad 4311, the signal pad 4312 and the second ground pad 4313 on the pad 4310 and the pad on the flexible circuit board are welded together without impedance continuity, the signal quality changes, and the signal integrity deteriorates.

The impedance of the welding position of the signal pad, the grounding pad and the flexible circuit board on the ceramic transfer block 430 is related to the dielectric constant of the ceramic transfer block 430, and when the dielectric constant is smaller, other parameters are unchanged, so that the impedance is increased, therefore, the impedance of the ceramic transfer block 430 can be improved by reducing the dielectric constant of the ceramic transfer block 430, and the impedance discontinuous point of the welding position of the ceramic transfer block 430 and the flexible circuit board pad is reduced.

In the embodiment of the present application, in order to improve signal quality, reduce impedance discontinuity, and improve high frequency performance, an isolation groove is disposed between the signal pad and the ground pad of the pad 4310, and the isolation groove is recessed in the signal pad and the ground pad. The dielectric constant of the ceramic transfer block 430 is reduced by arranging the isolation groove on the boss 4310, no conductive medium is arranged in the isolation groove, and the dielectric constant of the medium around the isolation groove is reduced by the lower dielectric constant of the isolation groove, so that the impedance of the signal pad and the grounding pad around the isolation groove can be improved.

Specifically, a first isolation groove 4314 is disposed between the first ground pad 4311 and the signal pad 4312, a second isolation groove 4315 is disposed between the signal pad 4312 and the second ground pad 4313, and the first isolation groove 4314 and the second isolation groove 4315 are recessed in the first ground pad 4311, the signal pad 4312 and the second ground pad 4313 and extend from the left side to the right side of the pad 4310.

A first isolation groove 4314 is disposed between the first ground pad 4311 and the signal pad 4312 of the pad 4310, and when a second isolation groove 4315 is disposed between the signal pad 4312 and the second ground pad 4313, the first isolation groove 4314 and the second isolation groove 4315 extend from the outer wall of the ceramic transfer block 430 to the side surface of the pad 4310 facing the circuit board 300 along the left-right direction, that is, the length dimensions of the first isolation groove 4314 and the second isolation groove 4315 in the left-right direction are the same as the length dimensions of the signal pad and the ground pad on the pad 4310 in the left-right direction.

In addition, a first isolation groove 4314 is disposed between the first ground pad 4311 and the signal pad 4312 of the pad 4310, and when a second isolation groove 4315 is disposed between the signal pad 4312 and the second ground pad 4313, the first isolation groove 4314 extends from the front side of the first ground pad 4311 to the rear side of the signal pad 4312, and the second isolation groove 4315 extends from the front side of the signal pad 4312 to the rear side of the second ground pad 4313, i.e., the width of the first isolation groove 4314 in the front-rear direction may be equal to the distance between the first ground pad 4311 and the signal pad 4312, and the width of the second isolation groove 4315 in the front-rear direction may be equal to the distance between the signal pad 4312 and the second ground pad 4313.

In the embodiment of the present application, a width dimension of the first isolation groove 4314 in the front-to-back direction may also be smaller than a distance between the first ground pad 4311 and the signal pad 4312, and a width dimension of the second isolation groove 4315 in the front-to-back direction may also be smaller than a distance between the signal pad 4312 and the second ground pad 4313. As long as boss 4310 of ceramic transfer block 430 is provided with the isolation groove between signal pad and ground pad, the size restriction to the isolation groove of this application can set up according to actual conditions.

In the embodiment of the present application, an isolation groove may be disposed only between the signal pad and the ground pad on one side of the pad 4310, where the side where the isolation groove is disposed transmits a high-speed signal, and the side where the isolation groove is not disposed transmits a low-speed signal. For example, an isolation groove is arranged between the signal pad and the ground pad on the upper side of the boss 4310; isolation grooves can also be formed between the signal pads and the ground pads on two opposite sides of the boss 4310, that is, the upper side surface of the boss 4310 is provided with a first ground pad, a first signal pad and a second ground pad, the first signal pad is arranged between the first ground pad and the second ground pad, the pad on the first flexible circuit board 600 and the first ground pad, the first signal pad and the second ground pad on the upper side surface of the boss 4310 are welded together by soldering tin, so that the first flexible circuit board 600 is connected to the upper side surface of the boss 4310.

The underside of the boss 4310 is provided with a third ground pad, a second signal pad and a fourth ground pad, the second signal pad is disposed between the third ground pad and the fourth ground pad, and the pads on the second flexible circuit board 700 are soldered to the third ground pad, the second signal pad and the fourth ground pad on the underside of the boss 4310 by solder to connect the second flexible circuit board 700 to the underside of the boss 4310.

On the upper side surface of the boss 4310, a first isolation groove is arranged between the first ground pad and the first signal pad, and a second isolation groove is arranged between the first signal pad and the second ground pad; on the lower side surface of the boss 4310, a third isolation groove is provided between the third ground pad and the second signal pad, and a fourth isolation groove is provided between the second signal pad and the fourth ground pad.

In the embodiment of the present application, when the flexible circuit board is connected to the ceramic transfer block 430, the flexible circuit board covers the isolation groove formed on the ceramic transfer block 430. That is, when the first isolation groove 4314 and the second isolation groove 4315 are disposed on the upper side surface of the boss 4310 of the ceramic transfer block 430, and when the flexible printed circuit board is welded to the boss 4310 of the ceramic transfer block 430, the flexible printed circuit board covers the first ground pad 4311, the first isolation groove 4314, the signal pad 4312, the second isolation groove 4315, and the second ground pad 4313 on the boss 4310.

The first isolation groove, the second isolation groove, the third isolation groove and the fourth isolation groove arranged on the upper side surface and the lower side surface of the boss 4310 reduce the dielectric constant of the ceramic transfer block 430, thereby improving the impedance of the connection part of the grounding pad and the signal pad on the ceramic transfer block 430 and the flexible circuit board pad, reducing the impedance discontinuous point of the welding part of the ceramic transfer block 430 and the flexible circuit board pad, saving the space, ensuring the width of the pad, ensuring the stable process welding, and most importantly, improving the signal quality to the optimum, and ensuring the integrity of signal transmission.

The optical module provided by the embodiment of the application comprises a circuit board, a transmitter optical subassembly and a flexible circuit board, wherein the transmitter optical subassembly comprises a shell and a ceramic adapter block plated with a metal layer, one side of the shell is provided with an opening, one side of the ceramic adapter block is inserted into the shell through the opening, the other side of the ceramic adapter block is exposed out of the shell, and the shell and the ceramic adapter block form an airtight shell so as to place optical devices such as a laser component, a lens array, a wavelength division multiplexing component and a lens component of the transmitter optical subassembly into the airtight shell for airtight packaging; one end of the ceramic switching block, which is positioned in the airtight shell, is connected with the laser assembly through a gold thread, one end of the ceramic switching block, which is positioned outside the airtight shell, is provided with a boss, a signal pad and a grounding pad are arranged on a metal layer on the side surface of the boss side by side, one end of the flexible circuit board is connected with the ceramic switching block through the signal pad and the grounding pad on the boss, the other end of the flexible circuit board is connected with the circuit board, and a working signal generated on the circuit board is switched to the laser assembly through the flexible circuit board and the ceramic switching block so as to drive the laser assembly to generate a laser beam and realize the emission of light; an isolation groove is arranged between a signal pad and a grounding pad on the side face of a boss of the ceramic transfer block, the isolation groove is recessed in the signal pad and the grounding pad, no conductive medium exists in the isolation groove, the dielectric constant of the isolation groove is low, the dielectric constant of the medium around the isolation groove is reduced through the low dielectric constant of the isolation groove, the impedance of the signal pad and the grounding pad around the isolation groove is improved, the signal pad on the ceramic transfer block is reduced, the impedance discontinuous point of the welding position of the grounding pad and a flexible circuit board pad is improved, the quality of signal transmission between the ceramic transfer block and the flexible circuit board is improved, and the integrity of the signal transmission is ensured. In addition, the isolation groove is arranged on the metal layer of the ceramic adapter block exposed outside the shell, and the airtight packaging of the transmitter optical subassembly is not influenced.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A light module, comprising:

a circuit board;

2. The optical module according to claim 1, wherein the ceramic adapter block is provided with a boss exposed outside the housing, and the boss is integrally provided with the ceramic adapter block; the signal pad and the grounding pad are arranged on the side face of the boss connected with the ceramic adapter block.

3. The optical module of claim 2, wherein the signal pad and the ground pad are disposed on a side of the boss that is connected to the outer wall of the ceramic interposer, and the signal pad is disposed adjacent to the ground pad;

the ground pad includes first ground pad and second ground pad, the signal pad sets up first ground pad with between the second ground pad, first ground pad with be provided with first isolation groove between the signal pad, the signal pad with be provided with the second isolation groove between the second ground pad.

4. The optical module of claim 3, wherein the first isolation groove and the second isolation groove each extend from one side of the boss to the other side.

5. The optical module of claim 3, wherein a dimension of the first isolation trench in a front-to-back direction is equal to a spacing between the first ground pad and the signal pad.

6. The optical module of claim 3, wherein a dimension of the first isolation trench in a front-to-back direction is smaller than a spacing between the first ground pad and the signal pad.

7. The optical module of claim 3, wherein the flexible circuit board covers the first isolation slot and the second isolation slot.

8. The optical module according to claim 3, wherein a longitudinal dimension of the boss in the front-rear direction is identical to a longitudinal dimension of the ceramic transition block in the front-rear direction.

9. The optical module of claim 2, wherein the boss is spaced apart from opposite sides of the ceramic transition block.

10. The light module of claim 1, wherein the tosa comprises a laser assembly disposed within the housing; the ceramic switching piece is inserted the one end of casing is provided with the mounting groove, be provided with the pad on the mounting groove, the laser instrument subassembly pass through the gold thread with the pad is connected.