CN212647079U - Optical module - Google Patents

Optical module Download PDF

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Publication number
CN212647079U
CN212647079U CN202020661340.XU CN202020661340U CN212647079U CN 212647079 U CN212647079 U CN 212647079U CN 202020661340 U CN202020661340 U CN 202020661340U CN 212647079 U CN212647079 U CN 212647079U
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CN
China
Prior art keywords
laser chip
optical
backlight
light
circuit board
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Active
Application number
CN202020661340.XU
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Chinese (zh)
Inventor
张晓磊
于琳
葛建平
王扩
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Hisense Broadband Multimedia Technology Co Ltd
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Hisense Broadband Multimedia Technology Co Ltd
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Application filed by Hisense Broadband Multimedia Technology Co Ltd filed Critical Hisense Broadband Multimedia Technology Co Ltd
Priority to CN202020661340.XU priority Critical patent/CN212647079U/en
Application granted granted Critical
Publication of CN212647079U publication Critical patent/CN212647079U/en
Priority claimed from PCT/CN2021/080965 external-priority patent/WO2021218463A1/en
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Abstract

The application provides an optical module, its optical transmission subassembly includes laser chip, sets up the detector in a poor light at laser chip backlight face. Meanwhile, the photosensitive surface of the backlight detector is designed into a concave arc structure so as to collect light emitted from the backlight surface of the laser chip. The backlight detector is electrically connected with the circuit board, and further can send the collected data to related devices arranged on the circuit board, so that the monitoring of the light-emitting optical power of the laser chip is realized. The photosensitive surface of concave arc structure in this application compares with planar structure's photosensitive surface, can effectively reduce the reverberation of photosurface, and then can reduce the reverberation to the crosstalk of laser chip's preceding light-emitting, so when the encapsulation, need not the contained angle between the position of the detector in a poor light of strict control and the laser chip position. Moreover, the area of the photosensitive surface can be increased by the cambered surface structure, so that the luminous flux received by the backlight detector can be effectively increased, and the optical power detection precision of the backlight detector is improved.

Description

Optical module
Technical Field
The application relates to the technical field of optical fiber communication, in particular to an optical module.
Background
Due to the increasing demand for communication bandwidth in the field of optical fiber communication, global optical communication is in a rapid development period. In the field of high-speed data communication, in order to ensure that data can be transmitted at a high speed over a long distance, optical modules are generally used in the field to realize the transmission and reception of light with different wavelengths.
The existing optical module generally refers to an integrated module for photoelectric conversion, and for optical signal transmission, a laser or a mode that a laser cooperates with an electro-absorption modulator is generally used for converting an electrical signal from an upper computer into an optical signal. In order to ensure the stability of the output power of the laser, a backlight detector is usually provided, and the backlight detector is provided with a planar photosensitive surface to monitor the optical power of the laser, and then the front output optical power of the laser is calculated through the tested backlight power.
For high speed devices, light may be reflected from the light sensitive surface of the back light detector, and this reflected light may cause performance degradation of the optical signal. At present, the common practice for solving the above problems is as follows: the backlight detector rotates a certain angle in the horizontal direction, so that a certain included angle is formed between the photosensitive surface of the backlight detector and the cavity surface of the laser, but the backlight quantity received by the backlight detector is reduced by the method, so that the deflection angle of the backlight detector needs to be strictly controlled in the process in order to simultaneously ensure the backlight quantity received by the backlight detector and prevent the reflected light of the backlight detector from influencing light signals, and further certain difficulty is brought to the packaging process.
SUMMERY OF THE UTILITY MODEL
In view of the foregoing problems, embodiments of the present application provide an optical module.
A circuit board;
and the light emitting component is electrically connected with the circuit board.
The light emitting assembly includes:
the laser chip is electrically connected with the circuit board and comprises a light-emitting surface and a backlight surface, and light signals generated by the laser chip are emitted through the light-emitting surface;
the backlight detector is arranged on the backlight surface side of the laser chip and electrically connected with the circuit board, the photosensitive surface of the backlight detector faces the backlight surface, and the photosensitive surface is of a concave arc structure and is used for collecting light emitted from the backlight surface.
The optical module that this application example provided designs the photosurface of being shaded detector for concave arc structure to the photosurface faces the backlight of laser chip, with the light of gathering from the laser chip's that the backlight is launched. The backlight detector is electrically connected with the circuit board, and further can send the collected data to related devices arranged on the circuit board, so that the monitoring of the light-emitting optical power of the laser chip is realized. The photosensitive surface of the concave arc-shaped structure in the embodiment is compared with the photosensitive surface of the planar structure, reflected light of the photosensitive surface can be effectively reduced, and then crosstalk of the reflected light to front light of the laser chip can be reduced, so that when the laser chip is packaged, an included angle between the position of the backlight detector and the position of the laser chip does not need to be strictly controlled. Moreover, the area of the photosensitive surface can be increased by the cambered surface structure, so that the backlight quantity received by the backlight detector can be effectively increased, and the optical power detection precision of the backlight detector is improved.
Drawings
In order to more clearly illustrate the technical solution of the present invention, 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 inventive exercise.
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 provided in this embodiment;
fig. 4 is an exploded schematic structural diagram of an optical module provided in this embodiment;
fig. 5 is a schematic view of the whole structure of the light emitting assembly provided in this embodiment;
fig. 6 is a schematic cross-sectional view of a light emitting device according to the present embodiment;
fig. 7 is an exploded schematic view of the light emitting device according to the present embodiment;
fig. 8 is a schematic overall structure diagram of the housing provided in this embodiment;
fig. 9 is a first exploded schematic view of the housing provided in this embodiment;
fig. 10 is a schematic view of a second disassembled structure of the housing provided in this embodiment;
fig. 11 is a schematic structural diagram of the cover plate provided in this embodiment;
fig. 12 is a schematic view of a first cross-sectional structure of the housing provided in this embodiment;
fig. 13 is a schematic view illustrating a sealing manner of the cover plate and the lower housing according to the present embodiment;
FIG. 14 is a cross-sectional view taken in the direction A-A of the cover plate of FIG. 11;
fig. 15 is a schematic diagram of a second cross-sectional structure of the housing provided in this embodiment;
fig. 16 is a schematic view illustrating a disassembled structure of the optical window sheet, the optical window fixing member and the isolator according to this embodiment;
fig. 17 is an exploded view of a light emitting device and a housing according to an embodiment of the present disclosure;
fig. 18 is a schematic view illustrating an assembly structure of a light emitting device and a housing according to an embodiment of the present disclosure;
fig. 19 is an exploded view of a light emitting device according to an embodiment of the present disclosure;
fig. 20 is a schematic structural diagram of a spacer and a laser chip according to an embodiment of the present disclosure;
FIG. 21 is an exploded view of a gasket according to an embodiment of the present disclosure;
fig. 22 is a schematic backside structure view of a first ceramic substrate according to an embodiment of the present disclosure;
fig. 23 is an insertion loss simulation result of a gasket provided in an embodiment of the present application;
fig. 24 is a return loss simulation result of the gasket provided in the embodiment of the present application;
fig. 25 is a schematic structural diagram of a laser chip according to an embodiment of the present disclosure;
fig. 26 is a schematic structural diagram of a pad and a lead according to an embodiment of the present disclosure;
fig. 27 is a schematic structural diagram of a laser chip and a third diode according to an embodiment of the present disclosure;
fig. 28 is a schematic view of a first structure of a spacer, a laser chip and a backlight detector according to an embodiment of the present disclosure;
fig. 29 is a second structural schematic diagram of a spacer, a laser chip, and a backlight detector according to an embodiment of the present disclosure;
fig. 30 is a schematic view of a first structure of a backlight detector according to an embodiment of the present application;
fig. 31 is a schematic view of a first structure of a backlight detector according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments will be described clearly and completely with reference to the drawings in the embodiments, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, 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 invention.
One of the core elements of fiber optic communications is the conversion of optical to electrical signals. The optical fiber communication uses the optical signal carrying information to transmit in the optical fiber/optical waveguide, and the information transmission with low cost and low loss can be realized by using the passive transmission characteristic of the light in the optical fiber. The information processing devices such as computers use electrical signals, which require the interconversion between electrical signals and optical signals during the signal transmission process.
The optical module realizes the photoelectric conversion function in the technical field of optical fiber communication, and the interconversion of optical signals and electric 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 a circuit board, main electrical connections comprise power supply, I2C signals, data signal transmission, grounding and the like, the electrical connection mode realized by the golden finger becomes a standard mode of the optical module industry, and on the basis, the circuit board is a necessary technical characteristic in most optical modules.
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 an optical network unit 100, an optical module 200, an optical fiber 101, and a network cable 103;
one end of the optical fiber is connected with the far-end server, one end of the network cable is connected with the 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 and the network cable; and the connection between the optical fiber and the network cable is completed by an optical network unit with an optical module.
An optical port of the optical module 200 is connected with the optical fiber 101 and establishes bidirectional optical signal connection with the optical fiber; the electrical port of the optical module 200 is accessed into the optical network unit 100, and establishes bidirectional electrical signal connection with the optical network unit; the optical module realizes the mutual conversion of optical signals and electric signals, thereby realizing the connection between the optical fiber and the optical network unit; 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 unit 100, and the electrical signal from the optical network unit 100 is converted into an optical signal by the optical module and input to the optical fiber. The optical module 200 is a tool for realizing the mutual conversion of the photoelectric signals, and has no function of processing data, and information is not changed in the photoelectric conversion process.
The optical network unit is provided with an optical module interface 102, which is used for accessing an optical module and establishing bidirectional electric signal connection with the optical module; the optical network unit is provided with a network cable interface 104 for accessing a network cable and establishing bidirectional electric signal connection with the network cable; the optical module is connected with the network cable through the optical network unit, specifically, the optical network unit 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 unit is used as an upper computer of the optical module to monitor the work 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 unit and the network cable.
Common information processing apparatuses include routers, switches, electronic computers, and the like; the optical network unit 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 unit structure. As shown in fig. 2, the optical network unit 100 includes a circuit board 105, and a cage 106 is disposed on a surface of the circuit board 105; an electric connector is arranged in the cage 106 and used for connecting 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 convex structure such as a fin for increasing a heat radiation area.
The optical module 200 is inserted into an optical network unit, specifically, an electrical port of the optical module is inserted into an electrical connector in the cage 106, and an optical port of the optical module is connected with the optical fiber 101.
The cage 106 is positioned on the circuit board, enclosing the electrical connectors on the circuit board in the cage; the optical module is inserted into the cage, the cage fixes the optical module, and heat generated by the optical module is conducted to the cage through the optical module housing and finally diffused through the heat sink 107 on the cage.
Fig. 3 is a schematic structural diagram of an optical module 200 according to an embodiment of the present disclosure, and fig. 4 is an exploded structural diagram of the optical module 200 according to the present disclosure. As shown in fig. 3 and 4, an optical module 200 provided in an embodiment of the present application includes an upper housing 201, a lower housing 202, an unlocking handle 203, a circuit board 30, a light emitting module 50, and a light receiving module 60.
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 unit; the other opening is an optical port 205 for external optical fiber access to connect the optical transmitting assembly 50 and the optical receiving assembly 60 inside the optical module; optoelectronic devices such as circuit board 30, light emitting assembly 50 and light receiving assembly 60 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 30, the light emitting assembly 50, the light receiving assembly 60 and other devices can be conveniently installed in the shells, and the upper shell and the lower shell form an outermost packaging protection shell of the optical module; the upper shell and the lower shell are made of metal materials generally, so that electromagnetic shielding and heat dissipation are facilitated; generally, the shell of the optical module cannot be made into an integrated structure, so that when devices such as a circuit board and the like are assembled, the positioning component, the heat dissipation structure and the electromagnetic shielding structure cannot be installed, and the production automation is not facilitated.
The unlocking handle 203 is located on the outer wall of the wrapping cavity/lower shell 202 and 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 handle 203 is provided with a clamping structure matched with the upper computer cage; the tail end of the unlocking handle is pulled to enable the unlocking handle 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 through a clamping structure of the unlocking handle; by pulling the unlocking handle, the clamping structure of the unlocking handle moves along with the unlocking handle, so that the connection relation between the clamping structure and the upper computer is changed, the clamping relation between the optical module and the upper computer is relieved, and the optical module can be drawn out from the cage of the upper computer.
The circuit board 30 is provided with circuit traces, electronic components (such as capacitors, resistors, triodes, and MOS transistors), and chips (such as the microprocessor MCU2045, the laser driver chip, the limiting amplifier, the clock data recovery CDR, the power management chip, and the data processing chip DSP).
The circuit board 30 connects the electrical devices 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 30 is generally a rigid circuit board, which can also realize a bearing function due to its relatively hard material, for example, the rigid circuit board can stably bear a chip; the rigid circuit board may also provide a smooth load bearing when the light emitting assembly 50 and the light receiving assembly 60 are located on the circuit board; 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 optical transmitter module 50 and the optical receiver module 60 are respectively used for transmitting and receiving optical signals. The light emitting assembly 50 in this embodiment is packaged coaxially, physically separated from the circuit board 30, and electrically connected through the flexible board 40; the light receiving element 60 is disposed on the surface of the circuit board 30, and of course, is packaged coaxially, and is physically separated from the circuit board, and is electrically connected through a flexible board.
Fig. 5 is a schematic overall structure diagram of the light emitting assembly provided in this embodiment, fig. 6 is a schematic cross-sectional structure diagram of the light emitting assembly provided in this embodiment, and fig. 7 is a schematic exploded structure diagram of the light emitting assembly provided in this embodiment. As shown in fig. 5 to 7, the light emitting assembly in the present embodiment mainly includes a housing 51, a sealing tube body 52, an adjusting sleeve 53, and a fiber adapter 54.
In order to achieve electromagnetic shielding and heat dissipation of the device, the housing 51 is generally made of a metal material. The light emitting device 70 is arranged in the shell 51, one end of the shell 51 is electrically connected with the flexible board 40 through a pin, the other end of the shell is connected with one end of the sealing welding tube body 52, a focusing lens can be arranged in the sealing welding tube body 52, the other end of the sealing welding tube body 52 is abutted against one end of the adjusting sleeve 53, and the sealing welding tube body 52 and the adjusting sleeve 53 are welded together through a solder. The other end of the adjusting sleeve 53 is sleeved on the optical fiber adapter 54, and during packaging, by adjusting the relative positions of the optical fiber adapter 54 and the adjusting sleeve 53, the focal point of the focusing lens in the sealing and welding tube body 52 is located at the light inlet of the optical fiber adapter 54 to ensure the optical coupling efficiency, and then, the optical fiber adapter 54 and the adjusting sleeve 53 are welded together.
In the signal transmission process, the optical transmitter 70 in the housing 51, after receiving the electrical signal transmitted from the flexible board 40, converts the electrical signal into an optical signal, and then the optical signal passes through the sealing and welding tube 52 and the adjusting sleeve 53 in sequence, enters the optical fiber adapter 54, and is transmitted to the outside of the optical module.
In order to protect the light emitting device 70 in the housing 51 during the use of the optical module, the housing 51 in this embodiment is hermetically sealed. Fig. 8 is a schematic overall structure diagram of the housing provided in this embodiment, and fig. 9 is a schematic first exploded structure diagram of the housing provided in this embodiment.
As shown in fig. 8 and 9, the housing 51 of the present embodiment includes a cover 511 and a lower housing 512, the lower housing 512 is designed as a cavity structure with an open top, and the cover 511 is fastened to the lower housing 512. To achieve a sealing effect within the housing 51, the present embodiment provides that the light emitting device 70 within the housing 51 is connected to an external circuit board via pins 514, wherein, the pin 514 is designed to be in a shape matched with the lower shell 512, a first end of the pin 514 is inserted into the lower shell 512, and plated with metal traces on the first end, the light emitting device 70 can be electrically connected to the corresponding metal traces by wire bonding, the end of the lead 514 disposed on the housing 512 is provided with a plurality of pins electrically connected to the metal traces, by inserting the pins into the flexible board 40 and soldering together, the flexible board 40 is then soldered to the circuit board 30, thereby achieving electrical connection of the light emitting device 70 within the housing 51 to the circuit board 30, of course, the electrical connection of the light emitting device 70 to the circuit board 30 may also be achieved by soldering the pins on the pins 514 directly to the circuit board 30.
In addition, as shown in fig. 6, in order to allow the signal emitted from the light emitting device 70 to pass through the housing 51 and be emitted to the outside of the housing, in the light emitting direction of the light emitting device 70, a through hole is opened in the housing 51, and a transparent light window sheet 55 is sealed in the through hole in order to ensure the sealing property of the housing 51. In order to facilitate fixing of the light window sheet 55, as shown in fig. 8 and 9, the present embodiment is further provided with a light window fixing member 513 at the other end of the lower case 512, and the light window is provided in the light window fixing member 513.
Fig. 10 is a schematic view of a second disassembled structure of the housing provided in this embodiment. As shown in fig. 10, based on the above-mentioned structure of the lead 514 and the lower housing 512, in order to facilitate the lead 514 to be quickly mounted on the lower housing 512, in this embodiment, the lower housing 512 is configured to be composed of a frame 512a and a lower cavity 512b, wherein one end of the lower cavity 512b is provided with a notch for mounting the lead 514, and after the lead 514 is inserted into the notch formed on the lower cavity 512b according to the direction indicated by the arrow in fig. 10, the frame 512a is fixed on the lower cavity 512 b. In order to facilitate the installation of the frame 512a, in this embodiment, after the leads 514 are installed in the lower cavity 512b, the upper surfaces of the leads 514 are flush with the upper surface of the sidewall of the lower cavity 512b, and the lower surface of the frame 512a is designed to be a flat surface.
Further, after the mounting of the respective devices in the case 51 is completed, the lid 511 is engaged with the lower case 512 and then both are welded to each other, and in order to prevent the lid 511 from sliding with respect to the lower case 512 and causing welding misalignment when both are welded. Fig. 11 is a schematic structural diagram of the cover plate provided in this embodiment. As shown in fig. 11, the lower surface of the cover plate 511 is configured to have a stepped structure, wherein, for convenience of description, the surface of the cover plate 511 close to the lower housing 512 is defined as the lower surface, and the surface far from the lower housing 512 is defined as the upper surface.
The lower surface of the cover plate 511 includes a first lower surface 511b and a second lower surface 511a located at the periphery of the first lower surface 511b, and the first lower surface 511b protrudes from the second lower surface 511 a. Thus, after the cover plate 511 is fastened to the lower housing 512, the second lower surface 511a contacts with the lower housing 512, that is, the cover plate 511 is welded to the lower housing 512 through the second lower surface 511a, the first lower surface 511b is disposed in the cavity of the lower housing 512, and meanwhile, the positioning of the cover plate 511 on the lower housing 512 can be realized by the step structure formed by the first lower surface 511b and the second lower surface 511 a. Further, in order to achieve better positioning of the cover 511, the present embodiment sets the distance between the inner wall of the lower housing 512 and the step surface 511c formed between the first lower surface 511b and the second lower surface 511a to be greater than 0 and smaller than a preset distance value, and the present embodiment refers to the surface connecting the first lower surface 511b and the second lower surface 511a as the step surface 511c, wherein the preset distance value may be set according to the requirement of the thickness of the sidewall of the lower housing 512 and the alignment precision of the cover 511 and the lower housing 512, for example, the preset distance value is designed to be 0.1mm, 0.5mm, and the like.
Fig. 12 is a schematic view of a first cross-sectional structure of the housing provided in this embodiment, and fig. 13 is a schematic view of a sealing manner between the cover plate and the lower housing provided in this embodiment. As shown in fig. 12, after the cover 511 is fastened to the lower case 512, a solder, such as an indium solder having a low melting point, is provided on the cover 511 and the lower case 512. As shown in fig. 13, two electrodes of the welding device are disposed on the upper surface of the cap 511, and the two electrodes are respectively disposed at two parallel sides on the cap 511, thereby becoming parallel sealing. The principle of sealing welding belongs to resistance welding, the electrodes rotate under the drive of electrode wheels while moving, and the electrodes are intermittently electrified under certain pressure, and contact resistance exists between the electrodes and the cover plate 511 and between the cover plate 511 and the lower shell 512. According to the formula of energy Q ═ I2Rt, the welding current will generate joule heat at the two contact resistances, so that the solder between the cover plate 511 and the lower housing 512 is molten, and the solder solidifies to form a solder joint.
The step formed by the first lower surface 511b and the second lower surface 511a is utilized to realize the positioning of the buckling position of the cover plate 511 on the lower shell 512, so that the cover plate 511 can be effectively prevented from sliding relative to the lower shell 512 during welding, especially in the process that the electrode turns from one side of the cover plate 511 to the other side, the cover plate is easy to slide relative to the lower shell due to the twisting of the electrode, so that the sealing is causedWelding dislocation. In addition, since the stepped cover plate has a smaller edge thickness than a non-stepped cover plate, the resistance at the edge position is larger, and the energy formula Q is I2Rt, at the same current, so that the temperature at which the cap plate 511 contacts the lower case 512 is higher, and it is easier to weld the two together. Therefore, the notch cuttype apron structure that this embodiment provided can effectively improve the welding quality of tube, realizes the effective sealing protection to holding the light emitting device/in it.
Fig. 14 is a sectional view of the cover plate of fig. 11 in the direction of a-a. As shown in fig. 14, a step surface 511c is formed between the first lower surface 511b and the second lower surface 511a, and an included angle θ between the step surface 511c and the second lower surface 511a is greater than 90 ° and less than 180 °, that is, the step between the first lower surface 511b and the second lower surface 511a is designed to have a certain chamfer structure, so that the cover plate 511 can be conveniently fastened to the lower housing 512, and in addition, the included angle between the step surface 511c and the second lower surface 511a can be prevented from being too small, which may cause the accumulation of charges during sealing. As shown in fig. 11 to 14, in order to reduce the accumulation of charges during sealing, in the present embodiment, if the housing 51 has a square shape, the cover 511 is also designed to have a square structure, and the corners of the cover 511 are designed to be arc-shaped corners; to achieve the positioning of the cover 511 on the lower case 512, the first lower surface 511b is also designed as a square structure, and the corners of the first lower surface 511b are designed as arc-shaped corners; in addition, the corner between the first lower surface 511b and the step surface 511c is also designed as an arc-shaped corner, i.e., the first lower surface 511b and the step surface 511c are in a circular arc-shaped transition.
It should be noted that the above-mentioned assembly manner between the cover plate 511 and the lower housing 512 in the housing 51 is not only suitable for the light emitting module, but also suitable for the light receiving module, that is, the housing of the light emitting module also includes a cover plate and a hollow lower housing, and the surface of the cover plate close to the lower housing also includes a first lower surface and a second lower surface located at the periphery of the first lower surface, and the first lower surface protrudes from the second lower surface, and the cover plate is welded on the lower housing through the second lower surface; the light receiving device is arranged in a sealed cavity formed by the cover plate and the lower shell so as to convert the data optical signal received by the optical module into a data electric signal and transmit the data electric signal to the circuit board. In addition, reference may be made to the above-described embodiments for other designs of the cover plate and the lower case.
Fig. 15 is a schematic diagram of a second cross-sectional structure of the housing according to the embodiment. As shown in fig. 15, the light emitting device 70 is disposed in the sealed cavity formed by the cover plate 511 and the lower housing 512, and when the optical module is in operation, the light emitting device 70 receives the data electrical signal transmitted from the circuit board 30 and converts the data optical signal into a data optical signal, and the data optical signal is emitted through the optical window piece 55 disposed in the optical window fixing member 513, but of course, in other embodiments, the optical window piece 55 may be directly fixed on the housing 51. The optical window sheet 55 may be made of sapphire glass with good light transmittance, and of course, may be made of other materials, such as quartz glass.
In order to prevent the crosstalk problem of the light reflected by the light louver 55 to the light emitting device 70, the present embodiment sets the light louver 55 to be inclined with respect to the vertical direction while the data light signal emitted by the light emitting device 70 is irradiated to the light louver 55 in the horizontal direction. Note that the present embodiment defines the traveling direction of the light emitted by the light emitting device 70 as the horizontal direction, and defines the direction perpendicular to the traveling direction of the light as the vertical direction.
With the above arrangement, since the incident direction of the optical signal emitted by the light emitting device 70 on the optical window 55 has a certain included angle with the normal of the optical window 55, the light reflected by the optical window 55 will not return to the light emitting device 70 along the incident path of the optical signal, and further the influence of the reflected light on the light emitting device 70 can be effectively avoided.
Further, in consideration of the combined influence of the transmittance of the light window 55 and the reflected light on the light emitting device 70, the present embodiment sets the inclination angle of the optical surface of the light window 55 with respect to the vertical direction to be greater than 0 ° and less than or equal to 10 °, and preferably, the inclination angle of the optical surface of the light window 55 with respect to the vertical direction to be greater than 0 ° and less than or equal to 4 °.
Further, in order to avoid the influence of other light in the optical path entering the housing 51 on the light emitting device 70, the present embodiment is further provided with an optical isolator 56. Fig. 16 is a schematic view of a split structure of the optical window sheet, the optical window fixing member, and the isolator according to this embodiment. As shown in fig. 16, the optical window fixing member 513 is further provided with an optical window receiving chamber 513a for receiving the optical window 55 and a spacer receiving chamber 513b for receiving the spacer 56.
The isolator 56 is a passive device that allows light to pass through in one direction and prevents light from passing through in the opposite direction, and is used for limiting the propagation direction of light, so that light can only be transmitted in one direction, and light reflected by the optical fiber echo can be well isolated by the isolator 56, thereby improving the light wave transmission efficiency. Wherein the inner diameter of isolator accommodation chamber 513b matches the outer diameter of isolator 56 to facilitate positioning of isolator 56, such as by providing isolator accommodation chamber 513b with an inner diameter equal to the outer diameter of isolator 56 or by providing isolator accommodation chamber 513b with an inner diameter slightly larger than the outer diameter of isolator 56. Thus, at the time of packaging, the separator 56 is inserted into the separator accommodation chamber 513b, the outer wall of the separator 56 is brought into contact with the inner wall of the separator accommodation chamber 513b, and then the two are welded together with glue. Further, it is also possible to provide the length of the separator 56 longer than the depth of the separator accommodation chamber 513b, that is, after the separator 56 is accommodated in the separator accommodation chamber 513b, a part of the separator 56 is disposed outside the separator accommodation chamber 513b, so that the separator 56 can be taken out of the separator accommodation chamber 513b in an edge side subsequent to the need, if necessary, and on the other hand, the installation positioning of the separator 56 in the optical axis direction can be facilitated.
In addition, in order to facilitate fixing of the light louver 55, the present embodiment provides that the light louver 55 is disposed to be inclined in a direction away from the light emitting device 70, that is, in a direction of the spacer 55. For the convenience of setting the inclination angle of the optical window piece 55, the cavity wall for fixing the optical window piece 55 in the optical window piece accommodating cavity 513a is also designed to be a surface with a certain inclination angle relative to the vertical direction in the embodiment, and the specific inclination angle can be set according to the inclination angle requirement of the optical window piece 55. For example, if the inclination angle of the optical window piece 55 is required to be 2 °, the cavity wall of the optical window piece accommodating cavity 513a is also set to be 2 ° so that the optical window piece 55 is directly attached to the cavity wall without adjusting the placement angle of the optical window piece 55; meanwhile, a through hole is formed in the cavity wall, and the through hole is covered by the optical window sheet 55 to ensure the air tightness of the housing 51, and the optical signal emitted by the light emitting device 70 is emitted to the outside of the housing 51 after passing through the optical window sheet 55 and the through hole in sequence.
Fig. 17 is an exploded structural schematic view of a light emitting device and a housing provided in the embodiment of the present application, and fig. 18 is an assembled structural schematic view of the light emitting device and the housing provided in the embodiment of the present application. As shown in fig. 17 and 18, in order to make the light emitted from the light emitting device 70 coincide with the optical axes of the isolator 55 and the fiber adapter 54 and stabilize the operating temperature of the light emitting device 70 to avoid the problem of the wavelength drift of the emitted light, the light emitting device 70 in this embodiment includes a TEC (thermal electric cooler) 71, a heat sink 72, a spacer 73, a collimating lens 74, a laser core 75, and a backlight detector 77.
Fig. 19 is an exploded view of a light emitting device according to an embodiment of the present disclosure. As shown in fig. 17 to 19, a TEC71 is provided on the bottom plate 512c of the housing 51, a heat sink 72 is provided on the upper surface of the TEC71, a collimating lens 74 and a spacer 73 are provided on the upper surface of the heat sink 72, and a laser chip 75 is provided on the upper surface of the spacer 73.
TEC71 is used to conduct heat generated by laser chip 75 away from base plate 512 c. Specifically, TEC71 includes an upper heat exchange surface 711, a structural member 712, and a lower heat exchange surface 713. The top of the upper heat exchange surface 711 is provided with a heat sink 72, and the upper heat exchange surface 711 is used for absorbing heat generated by the laser chip 75 transferred from the gasket 73 on the heat sink 72. A structural member 712 is connected to the bottom of the upper heat exchange surface 711, the structural member 712 is fixed to the lower heat exchange surface 713, the structural member 712 is used for transferring heat absorbed by the upper heat exchange surface 711 to the lower heat exchange surface 713, and the lower heat exchange surface 713 is fixed to the bottom plate 512c, so that the heat of the lower heat exchange surface 713 can be conducted out of the housing 51 through the bottom plate 512 c. In this embodiment, the TEC71 further includes an electrode 714, and the electrode 714 is used to supply power to the TEC71, so as to achieve a heat dissipation effect. One end of the electrode 714 is electrically connected to the circuit board 30, the other end of the electrode 714 is fixed on the lower heat exchanging surface 713, and the circuit board 30 transmits electric power to the electrode 714 so as to ensure the normal operation of the TEC71 by the electrode 714.
The heat sink 72 may be made of a ceramic material with good thermal conductivity and high processing precision, and is certainly not limited to ceramic, and is configured to provide a flat bearing surface for the collimating lens 74 and the spacer 73, and at the same time, is further configured to adjust the heights of the laser chip 75 and the collimating lens 74 in optical path transmission, so that the optical axes of the two coincide with each other, and coincide with the optical axis of the isolator 56 and the optical axis of the optical fiber ferrule in the optical fiber adapter 54, thereby improving the optical coupling efficiency. The optical signal emitted from the laser chip 75 is collimated by the collimating lens 74 to avoid optical loss in long-distance transmission, and then enters the isolator 56, although the heat sink 72 may not be provided in other embodiments.
Fig. 20 is a schematic structural diagram of a pad and a laser chip according to an embodiment of the present disclosure. As shown in fig. 20, the spacer 73 includes an insulating and heat conducting layer 731 and a metal layer, and the insulating and heat conducting layer 731 can be made of a ceramic material with good heat conduction performance, good insulation performance and high processing precision, but is not limited to ceramic. In order to facilitate the mounting of each electrical component on the pad 73, the metal layers disposed on the upper surface of the insulating and heat conducting layer 731 include a first ground metal layer 733 and a high-speed signal line 734, and the lower surface of the insulating and heat conducting layer 731 is in contact with the heat sink 72.
If the high frequency signal transmission mode adopts the GSG (ground-signal-ground) mode, the first ground metal layer 733 may be routed on both sides of the high speed signal line 734. The first ground metal layer 733 is connected to a ground pin on the lead 514, and the ground pin on the lead 514 is connected to a ground layer on the circuit board 30 through the flexible board 40. A first end of the high-speed signal line 734 is connected to a high-speed signal pin on the pin 514, the pin 514 is connected to the circuit board 30 through the flexible board 40, and a high-frequency data signal transmitted from the circuit board 30 can be transmitted to the high-speed signal line 734 through the pin 514; a second end of the high-speed signal line 734 is electrically connected to the anode of the laser chip 75; meanwhile, the cathode of the laser chip 75 may be welded to the first ground metal layer 733 by using welding or conductive glue; in addition, the laser chip 75 can also be electrically connected to a dc bias pin on the pin 514 to drive the laser chip 75 to emit light. Thus, the laser chip 75 can emit a data optical signal based on the high-frequency data electrical signal transmitted through the high-speed signal line 734 when operating.
Because the laser chip 75 generates heat during operation, the highest temperature reached by the laser chip 75 during operation is recorded as Ton; when the laser chip 75 stops operating, it does not emit light, so the temperature of the laser chip 75 begins to decrease, and the temperature of the laser chip 75 is recorded as Toff. Generally, a temperature drift coefficient exists between the temperature and the working wavelength of the laser chip, and the coefficient is different from the temperature drift coefficient of different types of laser chips, but is generally between 0.1-0.15 nm/DEG C, namely, the emission wavelength is increased or decreased by one degree per liter, and the emission wavelength can drift by 0.1-0.15 nm. Therefore, every time the laser chip 75 is turned on, it emits light and generates heat, the temperature of the laser chip 75 rises from Toff and then remains stable to Ton, during which the temperature of the laser chip changes dramatically and the emission wavelength of the laser chip 75 also shifts. In order to solve this problem, in the present embodiment, the heating resistor 761 is provided on the pad 73, and the heating resistor 761 is provided close to the laser chip. Meanwhile, the heating resistor 761 is arranged to heat the laser chip 75 when the laser chip 75 is turned off, so as to stabilize the temperature of the laser chip 75, and reduce the temperature difference between the on and off states of the laser chip 75, and the emitted emission wavelength drift caused by the temperature difference.
Further, as the transmission rate of the optical module increases, the requirement for insertion loss introduced by the high-speed signal line 734 is also higher, and therefore, in the present embodiment, the high-speed signal line 734 is designed to be a long strip structure with two straight sides, even if the high-speed signal line 734 is designed without bending, and then compared with the existing L-type, M-type and other signal lines with corners, the parasitic inductance at the bending position of the signal line can be reduced, and thus the insertion loss can be reduced, which is helpful for improving the high-frequency performance of the optical module.
The high-speed signal line 734 and the pin 514 may be connected by wire bonding, that is, connected by a metal wire, and the metal wire is usually set to be thinner, that is, has a smaller diameter, so that parasitic inductance introduced by the metal wire is larger, and the parasitic inductance introduced by the metal wire is also continuously increased along with the improvement of the communication rate of the optical module, so that the influence of the parasitic inductance on the high-speed photoelectric performance of the optical module is more and more obvious, and the width of the high-speed signal line 734 cannot be increased at will based on the impedance matching requirement between the high-speed signal line 734 and the laser chip 75 and the smaller and smaller area of the pad 73.
To solve the problem, in the present embodiment, the width of the first end portion of the high-speed signal line 734, which is used for being connected to the pin 514, is gradually widened along the reverse direction of the high-frequency data electrical signal transmission, that is, the first end portion of the high-speed signal line 734 is configured in a horn shape, so that the area of the first end portion of the high-speed signal line 734 is increased, the number of wires can be increased at the first end portion of the high-speed signal line 734, and further the total diameter of the metal wires can be increased, so that the inductance generated in the working process of the optical module can be reduced, which is beneficial to improving the high. Meanwhile, due to the fact that the width of the first end portion is in the gently widened structure, compared with the case that the first end portion is set to be a rectangular signal line, a square signal line and the like with corners, parasitic capacitance and inductance at the bent portion of the signal line can be reduced, insertion loss can be further reduced, and improvement of high-frequency performance of the optical module is facilitated.
However, the width of the first end of the high-speed signal line 734 is gradually widened, which makes the tip of the high-speed signal line 734 have a sharp angle, which is not good for its high-frequency performance, and the portion near the sharp angle is inconvenient for wire bonding due to its small area. Therefore, as shown in fig. 20, the present embodiment provides that the first end portion of the high-speed signal line 734 includes a first sub-end portion 734a and a second sub-end portion 734b, wherein one end of the first sub-end portion 734a is connected to the middle portion of the high-speed signal line 734, and the other end is connected to the second sub-end portion 734b, and the width thereof is gradually widened in the opposite direction of the data electrical signal transmission, i.e. the first sub-end portion 734a is designed to be a trapezoid structure, and at the same time, the second sub-end portion is designed to be a rectangular structure. Thus, the area of the first end portion can be increased, and the problem of sharp corners at the end of the high-speed signal line 734 can be avoided.
Furthermore, since the high-speed signal line 734 has a certain resistance, if the impedance of the high-speed signal line 734 and the impedance of the laser chip 75 are not matched, the signal output by the high-speed signal line 734 may be seriously degraded, therefore, in this embodiment, a matching resistor 762 is further disposed on the pad 73, wherein a first end of the matching resistor 762 is electrically connected to the anode of the laser chip 75, a second end of the matching resistor 762 is connected to the first ground metal layer 733, and a resistance value of the matching resistor 762 is equal to a resistance value of the high-speed signal line 734, so as to implement impedance matching between the laser chip 75 and the high-speed signal line 734. For example, if the laser chip 75 is an electro-absorption modulated laser chip, and the anode pad of the electro-absorption modulated laser chip includes an electro-absorption modulator pad and a laser pad, the electro-absorption modulator pad can be electrically connected to the second end of the high-speed signal line 734 and the matching resistor 762, respectively, by wire bonding, and the laser pad can be electrically connected to the laser driver chip on the circuit board 30 by wire bonding.
Preferably, the matching resistor 762 is designed to be composed of a first matching resistor and a second matching resistor connected in series, wherein a first end of the first matching resistor is connected to the anode of the laser chip 75, a second end of the first matching resistor is connected to a first end of the second matching resistor, a second end of the second matching resistor is connected to the first ground metal layer 733, and resistance values of the first matching resistor and the second matching resistor are each half of a resistance value of the high-speed signal line 734. Therefore, the influence of resistance value precision of the resistor on impedance matching can be reduced, in addition, an important factor is also provided, if the resistor parasitic with weak resistance is considered, the series design of the first matching resistor and the second matching resistor is equivalent to a distributed parasitic capacitor, and further, the high-frequency effect can be benefited in a high-frequency band.
In order to filter noise in the signal transmitted from the high-speed signal line 734 to the laser chip 75, in this embodiment, a filter capacitor 763 is further disposed on the pad 73, wherein a first end of the filter capacitor 763 is connected to the anode of the laser chip 75, and a second end of the filter capacitor 763 is connected to the first ground metal layer 733.
Fig. 21 is an exploded schematic structural diagram of a gasket according to an embodiment of the present application. As shown in fig. 21, the insulating and heat conducting layer 731 in this embodiment includes a first insulating and heat conducting layer 731a and a second insulating and heat conducting layer 731b, wherein a second ground metal layer 732 is disposed between the first insulating and heat conducting layer 731a and the second insulating and heat conducting layer 731b, and the second ground metal layer 732 can be coated on the lower surface of the first insulating and heat conducting layer 731 a. The high-speed signal line 734 and the first ground metal layer 733 located at two sides of the high-speed signal line 734 are disposed on the upper surface of the first insulating heat conduction layer 731a, and a ground hole 735 is disposed on the first ground metal layer 733, and the ground hole 735 penetrates through the first insulating heat conduction layer 731a and then is connected to the second ground metal layer 732.
In this embodiment, the grounding hole 735 is formed around the high-speed signal line 734 and electrically connected to the second grounding metal layer 732, so that not only the grounding area can be increased, but also the shortest signal return path can be provided for the high-speed signal line 734, and the area surrounded by the return paths of the differential signals is reduced, so as to reduce electromagnetic interference radiation of the signals, further reduce signal loss, ensure signal integrity, and increase high-frequency performance. In addition, the insulating and heat conducting layer 731 is designed to sandwich the second ground metal layer 732, and the ground hole 735 can directly penetrate through the first insulating and heat conducting layer 731a to connect with the second ground metal layer 732, so that the signal to ground loop can be made shorter, and the grounding effect can be increased.
Fig. 22 is a schematic back side structure view of a first ceramic substrate according to an embodiment of the present disclosure. As shown in fig. 22, in order to ensure the signal reflow symmetry, the ground holes 735 near the two sides of the high-speed signal line 734 are designed to be symmetrically distributed, i.e. symmetrically arranged on the left and right sides, where the direction perpendicular to the signal flow direction is defined as the left and right direction in this embodiment.
In order to further increase the grounding area, a third grounding metal layer (not shown) is further plated on the sidewall of the first insulating and heat conducting layer 731a, and the third grounding metal layer is electrically connected to the first grounding metal layer 733. Fig. 23 is an insertion loss simulation result of the gasket provided in the embodiment of the present application, and fig. 24 is a return loss simulation result of the gasket provided in the embodiment of the present application. As shown in fig. 23 and 24, it can be proved that, after the ground layer is plated on the side wall of the first insulating and heat conducting layer 731a, the area of the first ground metal layer 733 is effectively increased without increasing the area of the pad 73, and the high-frequency performance thereof is greatly improved.
Based on the structure of plating the third ground metal layer on the sidewall of the first insulating and heat conducting layer 731a, in order to prevent the third ground metal layer from being connected to the second ground metal layer 732, as shown in fig. 22, the area of the second ground metal layer 732 is smaller than that of the first insulating and heat conducting layer 731a, that is, the edge of the second ground metal layer 732 has a certain distance from the edge of the first insulating and heat conducting layer 731 a. Thus, when the third ground metal layer is formed on the sidewall of the first insulating and heat conducting layer 731a, the height of the third ground metal layer does not need to be precisely controlled, for example, even if the third ground metal layer is plated on the sidewall of the second insulating and heat conducting layer 731b, there is no problem that the third ground metal layer is connected to the second ground metal layer 732. Note that, in this embodiment, the height of the third ground metal layer in the thickness direction of the first insulating and heat conducting layer 731a is referred to as "height of the third ground metal layer".
Further, as for the modulation method of the laser chip 75, a direct modulation method may be adopted, that is, a high-frequency data electrical signal is directly loaded on the laser, but this method has a low dispersion tolerance value and a short transmission distance, generally less than 80 km. Therefore, in this embodiment, an external modulation mode is adopted to obtain a larger dispersion tolerance value, the laser chip 75 is configured as an integrated device of an Electric Absorption Modulator (EAM) and a DFB laser (tunable laser), which is also called an electric absorption modulation (EML) laser, and the electric absorption modulator operating by using the quantum confinement Stark effect and the DFB laser determining the wavelength by using the internal grating coupling are integrated into one chip, so that the volume of the chip can be reduced to reduce the space occupation in the housing 51.
Fig. 25 is a schematic structural diagram of a laser chip according to an embodiment of the present application. As shown in fig. 25, the electrodes on the upper surface thereof include an active area electrode 751, a grating reflection area electrode 752, a GND ground 753, and an electro-absorption modulator electrode 754. In packaging, the electrode on the lower surface of the laser chip, that is, the cathode thereof is fixed to the first ground metal layer 733 of the pad 73 by soldering or by means of conductive glue or the like, the active region electrode 751 and the grating reflection region electrode 752 are connected to the laser driver pin and the connection on the lead 514, the GND ground 753 is connected to the first ground metal layer 733, and the electro-absorption modulator electrode 754 is connected to the high-speed signal line 734. When the optical module works, the DFB laser is used for outputting light which does not carry signals, and the continuous output light of the DFB laser is subjected to amplitude modulation through the electro-absorption modulator to generate data optical signals; in addition, the current injected into the grating reflecting region electrode 752 of the DFB laser can be changed, so that the Bragg wavelength can be changed, the lasing wavelength can be changed, and the modulation of the output wavelength of the DFB laser can be realized.
Since the DFB laser has a major disadvantage that the DBR (Distributed Bragg reflector) is easily damaged by an overvoltage or ESD, the present embodiment provides a diode for limiting the voltage input to the grating reflective region electrode 752. Fig. 26 is a schematic structural diagram of a pad and a lead according to an embodiment of the present disclosure. As shown in fig. 26, a first diode 764 is provided on the pad 73. The anode of the first diode 764 is electrically connected to the grating reflective area electrode of the laser chip 75, wherein the laser chip 75 includes a tunable laser and an electro-absorption modulator, and is disposed in the housing, the anode of the tunable laser includes an active area electrode and a grating reflective area electrode, and the cathode of the first diode 764 is fixed on the first ground metal layer 733 of the pad 73 by welding or by means of conductive glue, etc. to achieve grounding.
The first diode 764 may be configured as a clamp diode, and the first diode 764 may clamp the voltage from several hundred volts to several tens of volts, and simultaneously undertake a large amount of voltage to flow away from the ground loop of the first diode 764, and input the clamped voltage to the grating reflective area electrode of the laser chip 75, thereby implementing an overvoltage and electrostatic surge protection circuit for the laser chip 75.
Further, in order to ensure the purity of the signal input to the grating reflective area electrode of the laser chip 75, a first capacitor 766 is further disposed on the pad 73, wherein one end of the first capacitor 766 is electrically connected to the grating reflective area electrode of the laser chip 75 and the anode of the first diode 764, and the other end is fixed to the first ground metal layer 733 of the pad 73 by welding or by conductive glue, so as to achieve grounding. First electric capacity 766, laser chip 75 and first diode 764 can be connected through the mode electricity of routing, and in order to prevent that the routing is too much on the laser chip, damage laser chip 75, laser chip 75 can be connected with the first end of first electric capacity 766 through the routing, then, the first end of first electric capacity 766 passes through the routing and the positive pole of first diode 764.
In this embodiment, the first capacitor 766 is connected in parallel with the laser chip 75 and the first diode 764, so that on one hand, noise in the signal transmitted to the laser chip 75 can be filtered out, and on the other hand, the first capacitor 766 is protected from being broken down by the first diode 764.
Similarly, in order to protect the active region of the laser chip 75, the embodiment further provides a second diode 765, wherein an anode of the second diode 765 is electrically connected to an electrode of the active region of the laser chip 75, and a cathode of the second diode 765 is fixed on the ground trace layer of the lead 514 by welding or by conductive glue, so as to achieve grounding.
In this embodiment, the second diode 765 is fixed on the lead 514, so that the internal space of the housing 51 can be fully utilized, and the problem of insufficient space caused by excessive components on the gasket 73 can be prevented. Of course, in other embodiments, other components may be mounted on the ground trace layer of pin 514, such as first diode 764 soldered on it and second diode 765 soldered on first ground metal layer 733 of pad 73.
The second diode 765 can clamp the voltage from hundreds of volts to tens of volts, simultaneously bear a large amount of energy to flow away from a circuit to the ground of the second diode 765, and input the clamped voltage to the electrode of the active area of the laser chip 75, thereby realizing an overvoltage and electrostatic surge protection circuit for the laser chip 75.
In order to ensure the purity of the signal input to the active area electrode of the laser chip 75, a second capacitor 767 is further disposed on the pad 73, wherein one end of the first capacitor 767 is electrically connected to the active area electrode of the laser chip 75 and the anode of the second diode 765, respectively, and the other end is soldered to the first ground metal layer 733 of the pad 73 to achieve grounding. In this embodiment, the first capacitor 766 is connected in parallel with the laser chip 75 and the second diode 765, so that on one hand, noise in the signal transmitted to the laser chip 75 can be filtered out, and on the other hand, the first capacitor 766 is protected from being broken down by the first diode 764.
Further, if the laser chip 75 adopts an electro-absorption modulation method, since the electro-absorption modulator is an intensity modulator, the absorption of the optical signal output by the laser by the modulator is controlled by adjusting the voltage, and in order to realize the optical signal with the modulation depth meeting the transmission requirement, extra loss is introduced in the modulation process, so that the output power of the laser chip 75 is limited. Therefore, in this embodiment, a semiconductor optical amplifier is further added to the laser chip 75 to amplify the optical signal output by the electro-absorption modulator. For example, to solve the problem of mode field matching between chips, a lens is required to perform mode field conversion between the electro-absorption modulator and the semiconductor optical amplifier, but the difficulty of the packaging process and the packaging cost of the device are increased.
Fig. 27 is a schematic structural diagram of a laser chip and a third diode provided in the embodiment of the present application. As shown in fig. 27, in the present embodiment, a laser, an electro-absorption modulator, and a semiconductor optical amplifier are integrated on the same substrate, and a laser chip integrating the above three devices is collectively referred to as a semiconductor optical amplifying laser, wherein an anode thereof includes a laser electrode 755, an electro-absorption modulator electrode 756, and a semiconductor optical amplifier electrode 757, and the laser electrode 755 may be electrically connected to a laser driving pin on the circuit board 30 through a pin 514, the electro-absorption modulator electrode 756 may be electrically connected to a high-frequency data signal pin on the circuit board 30 through a pin 514, and the semiconductor optical amplifier electrode 757 may be electrically connected to a semiconductor optical amplifier driving pin on the circuit board 30 through a pin 514. By utilizing the structure, the laser and the electric absorption modulator are connected through the first waveguide to form the optical signal output area, the electric absorption modulator and the semiconductor optical amplifier are connected through the second waveguide to form the signal amplification area, and the semiconductor optical amplifier amplifies and outputs the optical signal output by the electric absorption modulator. Of course, in other embodiments, the laser, the electroabsorption modulator, and the semiconductor optical amplifier may be provided as three separate devices, or the laser and the electroabsorption modulator may be integrated on one chip and the semiconductor optical amplifier may be provided separately.
However, the semiconductor optical amplifier is also easily damaged by overvoltage or ESD, and in order to solve this problem, the third diode 768 is provided in the case 51, and an anode of the third diode 768 is electrically connected to the semiconductor optical amplifier electrode 757, and a cathode of the third diode 768 is fixed to the first ground metal layer 733 of the pad 73, or may be soldered to the ground wiring layer of the pin 514 to realize grounding.
The third diode 768 can be configured as a clamp diode, and the voltage can be clamped from hundreds of volts to tens of volts by the third diode 768, and simultaneously, a large amount of energy is born to flow away from a ground loop of the third diode 768, and the clamped voltage is input to the semiconductor optical amplifier, so that an overvoltage and electrostatic surge protection circuit for the semiconductor optical amplifier can be realized.
Further, in order to ensure the purity of the signal input to the semiconductor optical amplifier, a third capacitor is further disposed on the housing 51, wherein one end of the third capacitor is electrically connected to the anode of the semiconductor optical amplifier and the anode of the third diode, and the other end of the third capacitor is soldered to the first ground metal layer 733 of the pad 73, or may be soldered to the ground wiring layer of the pin 514, so as to achieve grounding. In this embodiment, the third capacitor is connected in parallel with the laser chip 75 and the third diode, so that on one hand, noise in the signal transmitted to the laser chip 75 can be filtered out, and on the other hand, the third capacitor is protected from being broken down by the third diode.
By the arrangement of the matching components on the peripheries of the gasket 73 and the laser chip 75, the laser chip 75 can output high-quality optical signals while working safely. Among the optical signals emitted from the laser chip 75, the high-power optical signal propagates toward the fiber adapter 54 (forward propagation). Further, to ensure the stability of the optical power of the optical signal output by the laser chip 75.
As shown in fig. 26, a backlight detector 77 is further provided on the backlight surface side of the laser chip 75, wherein the light exit surface of the laser chip 75 faces the optical fiber adapter 54. The light sensing surface of the backlight detector 77 corresponds to a light outlet of the laser chip 75 that emits a light signal backward. The laser chip 75 emits an optical signal, wherein the high-power optical signal propagates toward the fiber adapter 54 (forward propagation), and the low-power optical signal propagates toward the back light detector 77 (backward propagation).
The low-power optical signal emitted by the laser chip 75 is received by the backlight detector 77, and the backlight detector 77 is configured to perform power monitoring on the low-power optical signal emitted by the laser chip 75, where the optical power entering the backlight detector 77 is generally much smaller than the total power of the optical waves emitted by the laser chip 75, and the power entering the backlight detector 77 for performing power detection is generally set to 1/10 of the total power, so as to monitor the front light optical power of the laser chip 75.
However, in the backlight detector 77 of fig. 26, a planar structure photosensitive member is attached to the ceramic base, and the photosensitive member reflects light, and the reflected light affects the forward optical path of the laser chip 75.
Fig. 28 is a schematic view of a first structure of a spacer, a laser chip, and a backlight detector provided in the embodiment of the present application, and fig. 29 is a schematic view of a second structure of the spacer, the laser chip, and the backlight detector provided in the embodiment of the present application.
The backlight detector 77 in this embodiment is provided on the spacer 73 and on the backlight surface side of the laser chip 75. Fig. 30 is a schematic view of a first structure of a backlight detector provided in the embodiment of the present application, and fig. 31 is a schematic view of a first structure of a backlight detector provided in the embodiment of the present application. As shown in fig. 28 to 30, the light-sensitive surface 772 of the backlight detector 77 is designed in a concave arc structure, and the light-sensitive surface 772 faces the backlight surface of the laser chip 75 to collect light emitted from the backlight surface of the laser chip 75. The backlight detector 77 is electrically connected to the circuit board 30, and further can send the collected data to a related device disposed on the circuit board 30, such as an MCU, to monitor the output optical power of the laser chip 75.
Like this, the photosurface 772 of the backlight detector 77 is of a concave arc structure, and compared with a planar structure, the reflected light of the photosurface 772 can be effectively reduced, so that the crosstalk of the reflected light to the front light of the laser chip 75 is reduced, and therefore, when the laser chip is packaged, the included angle between the position of the backlight detector 77 and the position of the laser chip 75 does not need to be strictly controlled. Moreover, the arc structure can increase the area of the photosensitive surface 772, thereby effectively increasing the backlight amount received by the backlight detector 77 and improving the optical power detection precision.
In order to further reduce crosstalk of the reflected light to the front light of the laser chip 75, so as to achieve the purpose of better monitoring the light power of the light emitted from the laser chip 75, in this embodiment, a normal line of the photosensitive surface 772 and a normal line of a backlight surface of the laser chip 75 have a certain included angle, and the included angle is optimally set to 4 to 8 degrees, but is not limited to changing the value.
Further, as shown in fig. 30 and 30, in order to facilitate wire bonding and a heterojunction structure combining with the photodiode, in the embodiment, the anode 771 is disposed on the upper surface of the backlight detector 77, and the cathode 774 is disposed on the lower surface of the backlight detector 77, so that the backlight detector 77 can be connected to the pin 514 by the anode 771 through wire bonding, and the cathode 774 can be directly welded or conductively fixed on the first grounding 733 metal layer of the pad 73 by means of conductive adhesive or the like, thereby achieving electrical connection between the backlight detector 77 and the circuit board 30.
In order to ensure the working performance of the backlight detector 77 and to take the backlight light-emitting path of the laser chip 75 into consideration, the light-sensitive surface 772 of the present embodiment is disposed near the bottom of the backlight detector 77, that is, the end surface of the backlight detector 77 near the laser chip 75 includes the light-sensitive surface 772 and a side wall surface 773 located above the light-sensitive surface, where the side wall surface 773 may be a vertical surface, or certainly, an inclined surface. Meanwhile, the distance between the photosensitive surface 772 and the backlight surface of the laser chip 75 is gradually increased along the top-to-bottom direction of the backlight detector 77, for example, the photosensitive surface 772 is designed to be a quarter-arc or elliptical arc structure, so as to reduce the crosstalk of the reflected light of the photosensitive surface 772 on the front light of the laser chip 75.
In the present embodiment, the surface of the backlight detector 77 that contacts the spacer 73 is referred to as a lower surface thereof, and the surface opposite to the lower surface is referred to as an upper surface; in addition, the backlight detector 77 and the laser chip 75 are not limited TO the package on the pad 73, and may be other packages, for example, TO packages.
Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.
It will be understood that the present application is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims (5)

1. A light module, comprising:
a circuit board;
the light emitting component is electrically connected with the circuit board;
the light emitting assembly includes:
the laser chip is electrically connected with the circuit board and comprises a light-emitting surface and a backlight surface, and light signals generated by the laser chip are emitted through the light-emitting surface;
the backlight detector is arranged on the backlight surface side of the laser chip, is electrically connected with the circuit board, and has a photosensitive surface facing the backlight surface; the photosensitive surface is of a concave arc structure and is used for collecting light emitted from the backlight surface.
2. The light module of claim 1, wherein the photosurface is disposed proximate a bottom of the backlight detector;
and the distance between the photosensitive surface and the backlight surface is gradually increased along the direction from the top to the bottom of the backlight detector.
3. The optical module according to claim 1, wherein a normal line corresponding to an incident point of the optical signal on the photosensitive surface forms an angle with a normal line of the backlight surface.
4. The light module of claim 1 or 2, wherein the light emitting assembly further comprises a gasket, wherein:
the gasket comprises an insulating heat conduction layer, a grounding metal layer and a high-speed signal wire, wherein the grounding metal layer and the high-speed signal wire are arranged on the surface of the insulating heat conduction layer;
the cathode of the laser chip is electrically arranged on the grounding metal layer, the anode of the laser chip is electrically connected with the second end part of the high-speed signal wire through routing, and the first end part of the high-speed signal wire is electrically connected with the circuit board;
the lower surface of the backlight detector is provided with a cathode, the upper surface of the backlight detector is provided with an anode, the cathode of the backlight detector is arranged on the grounding metal layer in a conductive mode, and the anode is electrically connected with the circuit board through a routing.
5. The light module of claim 4, wherein the light emitting assembly further comprises a housing, wherein:
the shell is provided with a pin, one end of the pin is inserted into the shell and is connected with the grounding metal layer on the gasket in a routing mode, and the other end of the pin is electrically connected with the circuit board.
CN202020661340.XU 2020-04-26 2020-04-26 Optical module Active CN212647079U (en)

Priority Applications (1)

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CN202020661340.XU CN212647079U (en) 2020-04-26 2020-04-26 Optical module

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Application Number Priority Date Filing Date Title
CN202020661340.XU CN212647079U (en) 2020-04-26 2020-04-26 Optical module
PCT/CN2021/080965 WO2021218463A1 (en) 2020-04-26 2021-03-16 Optical module

Publications (1)

Publication Number Publication Date
CN212647079U true CN212647079U (en) 2021-03-02

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021218463A1 (en) * 2020-04-26 2021-11-04 青岛海信宽带多媒体技术有限公司 Optical module

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021218463A1 (en) * 2020-04-26 2021-11-04 青岛海信宽带多媒体技术有限公司 Optical module

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