CN113359248A

CN113359248A - Optical module

Info

Publication number: CN113359248A
Application number: CN202110612388.0A
Authority: CN
Inventors: 陈骁; 李静思; 刘志程
Original assignee: Hisense Broadband Multimedia Technology Co Ltd
Current assignee: Hisense Broadband Multimedia Technology Co Ltd
Priority date: 2021-06-02
Filing date: 2021-06-02
Publication date: 2021-09-07
Anticipated expiration: 2041-06-02
Also published as: CN113359248B

Abstract

The application provides an optical module, includes: a light emitting module for generating and outputting signal light, including a laser; the laser includes: a laser chip for generating signal light; ceramic substrate, top are provided with the chip mounting groove, and the circuit has been laid to the top surface, the laser instrument chip sets up in the chip mounting groove, the laser instrument chip passes through routing connection the circuit. The application provides an optical module sets up the chip mounting groove on through ceramic substrate to set up laser chip in the chip mounting groove, can reduce laser chip top surface and ceramic substrate top surface difference in height, can guarantee the high frequency performance of laser instrument in the short within range with the routing length control between laser chip and the ceramic substrate, and then can guarantee the high frequency performance of optical module.

Description

Optical module

Technical Field

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

Background

The application markets of big data, block chains, cloud computing, internet of things, artificial intelligence and the like are rapidly developed, explosive growth is brought to data traffic, and the optical communication technology has gradually replaced traditional electrical signal communication in various industry fields due to the advantages of high unique speed, high bandwidth, low erection cost and the like. The semiconductor laser chip is a key device in modern optical fiber communication, and is a device which generates laser by using a semiconductor material as a working substance. Large data traffic places ever higher demands on high frequency performance of fiber optic communication systems, especially semiconductor lasers. The high frequency modulation performance of the laser is determined by the high frequency response of the active region and the high speed transmission structure. The high-speed transmission structure is crucial to the performance of high bandwidth and ultra-high bandwidth, and has become an important technical barrier affecting the performance of high-speed optical communication. The design of an optical module/optical device with excellent high-speed performance can obviously improve the key performance index and competitiveness of the product. Any impedance mismatch or resonance effects can severely degrade the performance of the overall product, resulting in a device that cannot be used at high speeds.

At present, CoC technology is commonly used in the industry to package lasers, i.e., a laser chip is mounted on a ceramic substrate, and the laser chip is bonded to RF circuits and the like of the substrate through gold wires, so as to realize interconnection between the laser chip and the ceramic substrate. Unlike the interconnect lines in digital circuits, the parameter characteristics of the gold bonding wires, such as number, length, camber, span, pad position, etc., can have a severe impact on high speed transmission characteristics. Especially at high speeds of 25Gbps and above, the parasitic inductance effect of the gold bonding wire is particularly obvious. The geometric parameters of the gold bonding wire affect the equivalent inductance, capacitance and resistance of the gold bonding wire, and accordingly, the interconnection characteristics are changed. And as the length of the gold bonding wire is shortened, the equivalent inductance of the gold bonding wire is reduced, and the insertion loss is also reduced. Therefore, how to reduce the length of the gold bonding wire and control the length of the gold bonding wire within a short range is a technical problem to be solved by those skilled in the art.

Disclosure of Invention

The embodiment of the application provides an optical module, which is convenient for controlling the routing length between a laser chip and a ceramic substrate within a short range.

The application provides a laser, including:

a light emitting module for generating and outputting signal light, including a laser;

the laser includes:

a laser chip for generating signal light;

ceramic substrate, top are provided with the chip mounting groove, and the circuit has been laid to the top surface, the laser instrument chip sets up in the chip mounting groove, the laser instrument chip passes through routing connection the circuit.

According to the optical module provided by the application, the light emitting component comprises a laser, and the laser comprises a laser chip and a ceramic substrate; a chip mounting groove is formed in the top of the ceramic substrate, and the laser chip is arranged in the chip mounting groove; and a circuit is laid on the top surface of the ceramic substrate, and the laser chip is connected with the circuit laid on the top surface of the ceramic substrate through routing. In the optical module that this application provided, through setting up the chip mounting groove on the ceramic substrate to set up the laser chip in the chip mounting groove, can reduce laser chip top surface and ceramic substrate top surface difference in height, can guarantee the high frequency performance of laser instrument in the short within range with the routing length control between laser chip and the ceramic substrate, and then can guarantee the high frequency performance of optical module.

Drawings

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

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

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

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

FIG. 4 is a schematic diagram of an exploded structure of an optical module according to an embodiment of the present application;

fig. 5 is a schematic diagram of an internal structure of an optical module according to an embodiment of the present disclosure;

fig. 6 is a schematic diagram of an tosa according to an embodiment of the present disclosure;

FIG. 7 is a schematic diagram illustrating a separated stem and cap structure of a light emitting module according to an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of a laser used in a light module in the prior art;

fig. 9 is a schematic structural diagram of a laser according to an embodiment of the present disclosure;

FIG. 10 is a schematic structural diagram of a first method for manufacturing a ceramic substrate with a chip mounting groove in the embodiment of the present application;

FIG. 11 is a first schematic structural view illustrating a second method for manufacturing a ceramic substrate with a chip mounting groove according to an embodiment of the present application;

FIG. 12 is a second schematic structural view illustrating a second method of manufacturing a ceramic substrate with a chip mounting groove according to an embodiment of the present application;

FIG. 13 is a schematic structural diagram of a ceramic substrate according to an embodiment of the present disclosure;

FIG. 14 is a schematic view of the ceramic substrate of FIG. 13 after mounting a laser chip thereon;

FIG. 15 is a first schematic structural view illustrating a chip mounting groove formed in a ceramic substrate according to an embodiment of the present disclosure;

FIG. 16 is a second schematic structural view illustrating a chip mounting groove formed in a ceramic substrate according to an embodiment of the present disclosure;

fig. 17 is a cross-sectional view of a ceramic substrate 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 an 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.

The fifth generation mobile communication technology (5G) currently meets the current growing demand for high-speed wireless transmission. The frequency spectrum adopted by the 5G communication is much higher than that adopted by the 4G communication, which brings a greatly improved communication rate for the 5G communication, but the transmission attenuation of the signal is relatively obviously increased.

The new service characteristics and higher index requirements of 5G provide new challenges for the bearer network architecture and each layer of technical solutions, wherein the optical module serving as a basic constituent unit of the physical layer of the 5G network also faces technical innovation and upgrade, which is mainly reflected in that the optical module applied to 5G transmission needs to have two basic technical characteristics of high-speed transmission and low return loss. In order to meet the requirement of an optical module in a 5G communication network, an embodiment of the present application provides an optical module.

Fig. 3 is a schematic diagram of an optical module according to an embodiment of the present disclosure, and fig. 4 is an exploded schematic diagram 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, a circuit board 203, a circular-square tube 300, a light emitting module 400, and a light receiving module 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 cover plate, and the cover plate covers two side plates of the upper shell to form a wrapping cavity; the upper shell can also comprise two side walls which are positioned at two sides of the cover plate and are perpendicular to the cover plate, and the two side walls are combined with the two side plates to realize that the upper shell covers 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; the photoelectric devices such as the circuit board 203, the round and square tube 300, the light emitting module 400 and the light receiving module 500 are positioned in the packaging cavity formed by the upper and lower shells.

The assembly mode of combining the upper shell 201 and the lower shell 202 is adopted, so that the round square tube body 300, the light emitting assembly 400, the light receiving assembly 500 and other devices can be conveniently installed in the shells, and the upper shell 201 and the lower shell 202 form an outermost packaging protection shell of the optical module; the upper shell 201 and the lower shell 202 are generally made of metal materials, which is beneficial to realizing electromagnetic shielding and heat dissipation; 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.

Typically, the optical module 200 further includes an unlocking component located on an outer wall of the package cavity/lower housing 202 for implementing a 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 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 203 is provided with circuit traces, electronic components (such as capacitors, resistors, triodes, and MOS transistors), and chips (such as an MCU, a clock data recovery CDR, a power management chip, and a data processing chip DSP).

The circuit board 203 connects the electrical appliances in the optical module together according to the circuit design through circuit wiring to realize the electrical functions of power supply, electrical signal transmission, grounding and the like.

The circuit board 203 is generally a rigid circuit board, which can also realize a bearing effect due to its relatively hard material, for example, the rigid 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.

The light emitting assembly and the light receiving assembly may be collectively referred to as an optical subassembly. As shown in fig. 4, in the optical module provided in this embodiment, the light emitting module 400 and the light receiving module 500 are both disposed on the circular-square tube 300, the light emitting module 400 is used for generating and outputting signal light, and the light receiving module 500 is used for receiving signal light from outside the optical module. The round and square tube 300 is provided with an optical fiber adapter for connecting an optical module with an external optical fiber, and the round and square tube 300 is usually provided with a lens assembly for changing the propagation direction of the signal light output from the optical transmission assembly 400 or the signal light input from the external optical fiber. The light emitting module 400 and the light receiving module 500 are physically separated from the circuit board 203, and therefore, it is difficult to directly connect the light emitting module 400 and the light receiving module 500 to the circuit board 203, so that the light emitting module 400 and the light receiving module 500 are electrically connected through flexible circuit boards, respectively, in the embodiment of the present application. However, in the embodiment of the present application, the assembling structure of the light emitting module 400 and the light receiving module 500 is not limited to the structure shown in fig. 3 and fig. 4, and other assembling and combining structures may also be used, for example, the light emitting module 400 and the light receiving module 500 are disposed on different tubes, and this embodiment is only exemplified by the structure shown in fig. 3 and fig. 4.

Fig. 5 is an internal structural schematic diagram of an optical module according to an embodiment of the present application. As shown in fig. 5, the optical module 200 provided in the embodiment of the present application includes a circular-square tube 300, a light emitting module 400, and a light receiving module 500. The light emitting assembly 400 is arranged on the round and square tube 300 and is coaxial with the optical fiber adapter of the round and square tube 300, and the light receiving assembly 500 is arranged on the side of the round and square tube 300 and is not coaxial with the optical fiber adapter; however, in the embodiment of the present application, the light receiving assembly 500 may be coaxial with the fiber optic adapter, and the light emitting assembly 400 may be non-coaxial with the fiber optic adapter. The light emitting module 400 and the light receiving module 500 are arranged in the round square tube 300, so that the control of the signal light transmission light path is convenient to realize, the compact design of the interior of the optical module is convenient to realize, and the occupied space of the signal light transmission light path is reduced. In addition, with the development of the wavelength division multiplexing technology, in some optical modules, more than one light emitting module 400 and light receiving module 500 are disposed on the circular square tube 300.

In some embodiments of the present application, a transflective lens is further disposed in the circular-square tube 300, and the transflective lens changes a propagation direction of the signal light to be received by the light receiving module 500 or changes a propagation direction of the signal light generated by the light emitting module 400, so as to facilitate the light receiving module 500 to receive the signal light or output the signal light generated by the light emitting module 400.

Fig. 6 is a structural diagram of an external shape of a light emitting module according to an embodiment of the present disclosure. As shown in fig. 6, the light emitting module 400 provided in this embodiment includes a tube socket 410, a tube cap 420, and other devices disposed in the tube cap 420 and the tube socket 410, wherein the tube cap 420 is covered at one end of the tube socket 410, the tube socket 410 includes a plurality of pins, and the pins are used for electrically connecting the flexible circuit board to other electrical devices in the light emitting module 400, and further electrically connecting the light emitting module 400 to the circuit board 203.

Fig. 7 is a schematic structural view illustrating a tube socket and a tube cap of a light emitting module according to an embodiment of the present disclosure. As shown in fig. 7, the light emitting module 400 includes a laser 600 therein, and the laser 600 generates signal light and the generated signal light passes through the cap 420.

Fig. 8 is a schematic structural view of a laser used in a light module in the prior art. As shown in fig. 8, the laser 06 includes a laser chip 061 and a ceramic substrate 062, and the laser chip 061 is disposed on a surface of the ceramic substrate 062. Wherein, the surface of the ceramic substrate 062 forms a circuit pattern, can supply power and transmit signals for the laser chip; meanwhile, the ceramic substrate 062 has better heat-conducting performance and can be used as a heat sink of the laser chip 061 for heat dissipation. The upper surface of the laser chip 061 is provided with a plurality of electrodes, the ceramic substrate 062 is provided with a bonding pad correspondingly connected with the surface circuit board, and the electrodes on the upper surface of the laser chip 061 and the corresponding bonding pad are connected through gold wire bonding.

As shown in fig. 8, the upper surface of the laser chip 061 is higher than the upper surface of the ceramic substrate 062, so the gold wire needs to be pulled out by a certain arc height from the bonding pad of the laser chip 061 to be bonded to the ceramic substrate 062, and the cleaver of the gold wire bonding is easily interfered with the laser chip, so the second welding point bonded to the ceramic substrate 062 has a certain distance from the laser chip 061, which results in the fact that the length of the whole gold wire cannot be controlled in a short range, and further causes a large parasitic inductance effect, and reduces the high-frequency performance of the laser.

Fig. 9 is a schematic structural diagram of a laser according to an embodiment of the present application. As shown in fig. 9, the laser 600 includes a laser chip 610 and a ceramic substrate 620, a circuit is laid on the upper surface of the ceramic substrate 620, and the laser chip 610 is connected to the corresponding circuit on the ceramic substrate 620 by a wire bonding; for example, the electrodes on the upper surface of the laser chip 610 are connected with the bonding pads on the ceramic substrate 620 by wire bonding. In order to control the gold wire for bonding the laser chip 610 and the ceramic substrate 620 within a relatively short range, a chip mounting groove 621 is formed in the ceramic substrate 620, the depth of the chip mounting groove 621 is close to or equal to the thickness of the laser chip 610, the laser chip 610 is attached in the chip mounting groove 621, so that the chip pad on the laser chip 610 is close to and consistent with the circuit wiring height on the ceramic substrate 620, and meanwhile, the width of the chip mounting groove is controlled (not only the laser chip is ensured to be accommodated, but also excessive residual space cannot be reserved after the laser chip is accommodated), so that the arc height of gold wire bonding can be shortest, the problem of riving knife interference does not exist, the length of the gold wire can be also made within a shorter range, and the high-frequency performance of the laser is improved. However, due to the characteristics of the ceramic substrate 620, the difficulty of processing is relatively high, and it is relatively difficult to process a chip mounting groove with a proper size.

In the embodiment of the present application, the chip mounting groove 621 may be a blind hole type chip mounting groove, and may also be a chip mounting groove that penetrates the width or length of the ceramic substrate 620. Optionally, as shown in fig. 9, the chip mounting groove 621 is a chip mounting groove penetrating through the width direction of the ceramic substrate 620, and when the laser chip 610 is assembled and fixed, the laser chip 610 is directly clamped along the width direction parallel to the ceramic substrate 620, so that the laser chip 610 is assembled and fixed conveniently.

The ceramic substrate 620 with the chip mounting groove 621 can be processed and prepared in two ways at present: firstly, two ceramic blanks on the uppermost layer are selected according to the depth of the required chip mounting groove 621, the ceramic blanks are aligned according to the width of the chip mounting groove 621, and then high-temperature sintering is carried out; second, the chip mounting groove 621 is directly etched on the sintered ceramic substrate 620 according to the size requirement of the chip mounting groove 621. Fig. 10 is a schematic structural diagram of a first method for manufacturing a ceramic substrate with a chip mounting groove in the embodiment of the present application. As shown in fig. 10, the two ceramic blanks on the top layer need to be formed with the ceramic blank below through high temperature sintering, and the size of the formed chip mounting groove 621 cannot be accurately ensured in the high temperature sintering forming process, so that the size of the chip mounting groove 621 formed by sintering forming is unstable, and the accurate requirement of the chip mounting groove 621 cannot be ensured. FIG. 11 is a first schematic structural diagram illustrating a second method for manufacturing a ceramic substrate with a chip mounting groove according to an embodiment of the present application. As shown in fig. 11, the ceramic substrate 620 after sintering and molding is directly etched according to the size of the chip mounting groove 621, but due to the characteristics of the etching process, the feet at the two sides of the chip mounting groove 621 formed by etching are formed into round corners, and the radius of the round corners is at least 0.1mm, so that the laser chip 610 can be clamped when being attached to the groove, and the laser chip 610 cannot be attached normally.

FIG. 12 is a second schematic structural view illustrating a second method for manufacturing a ceramic substrate with a chip mounting groove according to an embodiment of the present application. As shown in fig. 12, the width of the chip mounting groove 621 in fig. 12 is increased as compared with the chip mounting groove 621 in fig. 11. Thus, although the corner clipping problem can be solved by increasing the width of the slot body of the chip mounting groove 621, the length of the gold bonding wire can be increased, and the high-frequency performance of the laser 600 is reduced.

Fig. 13 is a schematic structural diagram of a ceramic substrate according to an embodiment of the present disclosure, and fig. 14 is a schematic structural diagram of the ceramic substrate in fig. 13 after a laser chip is mounted thereon. As shown in fig. 13 and 14, a chip mounting groove 621 is disposed on the ceramic substrate 620 provided in the embodiment of the present application, and the bottom of the chip mounting groove 621 includes a chip bearing surface 622, a first deepening groove 623 and a second deepening groove 624; the chip bearing surface 622 extends along the length extension direction of the chip mounting groove 621, the first deepening groove 623 is located at one side of the chip bearing surface 622 in the length direction, and the second deepening groove 624 is located at the other side of the chip bearing surface 622 in the length direction; the height difference between the bottom surface of the first deepening groove 623 and the top surface of the ceramic substrate 620 is greater than the height difference between the chip bearing surface 622 and the top surface of the ceramic substrate 620, the height difference between the bottom surface of the second deepening groove 624 and the top surface of the ceramic substrate 620 is greater than the height difference between the chip bearing surface 622 and the top surface of the ceramic substrate 620, namely, the depth of the first deepening groove 623 and the depth of the second deepening groove 624 in the chip mounting groove 621 are both greater than the depth of the chip bearing surface 622; laser chip 610 is disposed on chip carrier surface 622. The first deepening groove 623 and the second deepening groove 624 avoid corners of the laser chip 610, so that the corner clamping phenomenon in 11 is avoided, the laser chip 610 is arranged on the chip bearing surface 622, and the laser chip 610 is convenient to mount; meanwhile, the width of the chip mounting groove 621 does not need to be increased, so that the routing length between the laser chip 610 and the ceramic substrate 620 is conveniently controlled within a short range.

In this embodiment, it is also possible to provide the chip bearing surface 622 and the first deepening groove 623 only at the bottom of the chip mounting groove 621, or to provide the chip bearing surface 622 and the second deepening groove 624 only at the bottom of the chip mounting groove 621, and the purpose of avoiding the corner of the laser chip 610 is achieved by controlling the width of the first deepening groove 623 or the second deepening groove 624. In some embodiments of the present application, the height difference between the chip carrying surface 622 and the top surface of the ceramic substrate 620 is equal to or similar to the thickness of the chip carrying surface 622; optionally, the difference between the height of the chip carrying surface 622 and the top surface of the ceramic substrate 620 and the thickness of the chip carrying surface 622 is within ± 10 μm.

In fig. 13 and 14, the chip mounting groove 621 penetrates through the ceramic substrate 620, and the chip carrying surface 622 extends to the side of the ceramic substrate 620, but the present application is not limited to the embodiment shown in fig. 13 and 14, and the chip mounting groove 621 may not penetrate through the ceramic substrate 620 and the chip carrying surface 622 does not extend to the side of the ceramic substrate 620.

In the embodiment of the present application, the depth and width of the first and second

deepening grooves

623 and 624 may be generally selected according to the size of the fillet to be formed, and generally, the depth of the first and second

deepening grooves

623 and 624 is greater than the radius of the fillet, the diameter of the fillet, and the width and width of the first and second

deepening grooves

623 and 624.

The chip mounting groove 621, as shown in fig. 13 and 14, may be directly formed by engraving. Fig. 15 is a first structural schematic view of a chip mounting groove machined on a ceramic substrate according to an embodiment of the present disclosure, and fig. 16 is a second structural schematic view of a chip mounting groove machined on a ceramic substrate according to an embodiment of the present disclosure. As shown in fig. 15 and 16, first, the side edge of the chip mounting groove 621 is etched according to the size of the chip mounting groove 621, and the first deepening groove 623 and the second deepening groove 624 are etched at the bottom of the side edge, and then the middle portion of the first deepening groove 623 and the second deepening groove 624 are etched to etch the chip carrying surface 622, wherein the depth of the first deepening groove 623 and the depth of the second deepening groove 624 are both greater than the depth of the chip carrying surface 622. Like this, like the chip mounting groove 621 shown in fig. 13 and 14, can effectively avoid forming the fillet because of the sculpture and influence laser instrument chip 610 and paste dress because of forming chip mounting groove 621 in-process both sides footing, can avoid increaseing the cell body width of chip mounting groove 621 simultaneously again, do benefit to the routing length control between laser instrument chip 610 and ceramic substrate 620 in shorter scope, guarantee the high frequency performance of laser instrument.

In some embodiments of the present application, the ceramic substrate 620 is a multilayer board, and the number of layers of the ceramic substrate 620 is more than two, i.e., the ceramic substrate 620 includes at least two layers of ceramic green sheets. If a circuit needs to be laid on each layer of ceramic green body, the circuit can be manufactured on the ceramic green body in a printing mode and the like, then each layer of green body is aligned and then sintered and formed at high temperature, generally the temperature is over 1000 ℃, and finally the circuit is manufactured on the surface of the ceramic through a metal sputtering or evaporation process after the surface is polished.

In some embodiments of the present application, the chip bearing surface 622 may be located at the center of the chip mounting groove 621. The height difference between the bottom surface of the first deepening groove 623 and the top surface of the ceramic substrate 620 and the height difference between the bottom surface of the second deepening groove 624 and the top surface of the ceramic substrate 620 may be equal or different.

Fig. 17 is a cross-sectional view of a ceramic substrate according to an embodiment of the present disclosure, and fig. 17 shows that the ceramic substrate 620 is a double-layer ceramic substrate. As shown in fig. 17, the ceramic substrate 620 of the present embodiment includes a top plate 625 and a bottom plate 626, the top plate 625 and the bottom plate 626 are formed by high temperature sintering, and the chip mounting groove 621 is provided on the top plate 625.

Further, in some embodiments of the present application, the size of the ceramic substrate 620 is relatively small, and in order to meet the circuit requirements of the laser chip 610, the ceramic substrate 620 is not only provided with a circuit on the top surface, but also often needs to be provided with a circuit layer 627 inside, and the circuit layer 627 is used for forming a circuit. Therefore, as shown in fig. 17, a first circuit is laid on the upper surface of the top plate 625, a first extension circuit is laid on the lower surface of the top plate 625, a via 628 is formed on the top plate 625, and the first circuit is connected to the first extension circuit through the via; the laying of the first circuit and the first expansion circuit can be selected according to needs, and then the position and the number of the through holes 628 can be selected according to the first circuit and the first expansion circuit, which is not specifically limited in the embodiment of the present application.

Further, since the bottom surface of the laser chip 610 is provided with a laser chip cathode and the like, and needs to be connected to a circuit such as a ground on the ceramic substrate, in some embodiments of the present application, a metal layer connected to the first circuit is provided on the chip bearing surface 622, the bottom surface of the laser chip 610 is electrically connected to the metal layer, and the laser chip 610 is grounded through the metal layer. Optionally, the bottom surface of the laser chip 610 is fixed on the chip carrying surface 622 by solder, conductive silver paste, or the like; when the solder and the conductive silver paste are excessive in quantity, the excessive solder and the conductive silver paste can flow into the first deepening groove 623 and the second deepening groove 624, so that the excessive solder and the conductive silver paste are prevented from climbing on the side surface of the laser chip 610 to pollute the side surface of the laser chip 610, and the reliability of fixing the laser chip 610 is further ensured.

Finally, it should be noted that: the embodiment is described in a progressive manner, and different parts can be mutually referred; in addition, 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:

the laser includes:

a laser chip for generating signal light;

2. The optical module of claim 1, wherein the bottom of the chip mounting slot comprises a chip carrying surface, one side of the chip carrying surface is provided with a first deepening groove, and the other side of the chip carrying surface is provided with a second deepening groove;

the height difference between the bottom surface and the top surface of the first deepening groove is larger than that between the bearing surface and the top surface, and the height difference between the bottom surface and the top surface of the second deepening groove is larger than that between the bearing surface and the top surface;

the laser chip is arranged on the chip bearing surface, and the first deepening groove and the second deepening groove are used for avoiding the corners of the laser chip.

3. The optical module of claim 1, wherein the chip mounting slot penetrates the ceramic substrate.

4. The optical module of claim 1, wherein the ceramic substrate includes a top plate and a bottom plate, the chip mounting slot being disposed on the top plate.

5. The optical module according to claim 4, wherein a first circuit is laid on an upper surface of the top plate, a first extension circuit is laid on a lower surface of the top plate, a via hole is formed on the top plate, and the first circuit is connected to the first extension circuit through the via hole.

6. The optical module of claim 2, wherein the difference between the height of the carrying surface and the top surface is within ± 10 μm of the thickness of the laser chip.

7. The optical module of claim 2, wherein the bearing surface is located at a center of the chip mounting groove.

8. The optical module of claim 2, wherein a metal layer is disposed on the chip carrying surface, and the metal layer is electrically connected to the bottom surface of the laser chip.

9. The optical module of claim 2, wherein a plurality of electrodes are disposed on the upper surface of the laser chip, a plurality of bonding pads are disposed on the top surface of the ceramic substrate, and the electrodes are correspondingly connected to the bonding pads by wire bonding.

10. The optical module of claim 1, wherein the bottom of the chip mounting slot comprises a chip carrying surface;

a first deepening groove is formed in one side of the chip bearing surface, and the height difference between the bottom surface and the top surface of the first deepening groove is larger than that between the bearing surface and the top surface; or a second deepening groove is formed in the other side of the chip bearing surface, and the height difference between the bottom surface of the second deepening groove and the top surface is larger than that between the bearing surface and the top surface;

the laser chip is arranged on the chip bearing surface, and the first deepening groove or the second deepening groove is used for avoiding the corners of the laser chip.