An optical module

Abstract

The optical module provided in the application comprises a circuit board, a first laser chip electrically connected with the circuit board and capable of emitting light of a first wavelength and a second wavelength, a first filter receiving light emitted by the first laser chip and capable of reflecting light of the first wavelength and transmitting light of the second wavelength, a second laser chip electrically connected with the circuit board and capable of emitting light of the first wavelength and the second wavelength, a second filter receiving light emitted by the second laser chip and capable of reflecting light of the second wavelength and transmitting light of the first wavelength, and a combining assembly capable of receiving light of the first wavelength reflected by the first filter, receiving light of the second wavelength reflected by the second filter, and combining the received light of the first wavelength and the second wavelength into one beam.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to an optical module. Background Technology

[0002] Optical communication technology is used in emerging business and application models such as cloud computing, mobile internet, and video. Optical modules, which perform photoelectric conversion in optical communication technology, are one of the key components in optical communication equipment. The intensity of the optical signal input from the optical module into the external optical fiber directly affects the quality of optical fiber communication.

[0003] Some optical modules employ micro-optical form factor packaging for their light-emitting components. This means that the light emitted by the laser chip enters the air, and lenses, fiber optic adapters, and other devices are placed along the optical path to couple the light emitted by the chip through the lenses to the fiber optic adapter, which is then connected to an optical fiber. In micro-optical form factor packaging, to achieve high-efficiency output, the number of laser chips is usually not unique; that is, at least two laser chips are used.

[0004] However, during use, it was found that chirping occurs when the laser chip is turned on or off, such as negative chirping (redshift) from high to low frequency and positive chirping (blueshift) from low to high frequency. Although the crosstalk caused by chirping can be limited to one type, such as redshift or blueshift, by setting the temperature and current before the laser chip is turned on and off, chirping cannot be completely avoided. Assuming that the optical module includes at least laser chip 1 and laser chip 2, if laser chip 1 generates chirped output light with a wavelength of λ2, and laser chip 2 is specified to operate at a wavelength of λ2, then the λ2 light generated when laser chip 1 is turned on or off will cause chirping crosstalk to the λ2 light of laser chip 2 at its specified operating wavelength. Summary of the Invention

[0005] This application provides an optical module that avoids chirp crosstalk between laser chips when the laser chips in the optical module are turned on or off.

[0006] This application provides an optical module, including a circuit board; a first laser chip electrically connected to the circuit board, capable of emitting light of a first wavelength and a second wavelength; a first filter, capable of receiving light emitted by the first laser chip, reflecting light of the first wavelength, and transmitting light of the second wavelength; a second laser chip electrically connected to the circuit board, capable of emitting light of the first wavelength and the second wavelength; a second filter, capable of receiving light emitted by the second laser chip, reflecting light of the second wavelength, and transmitting light of the first wavelength; and a beam combiner, capable of receiving light of the first wavelength reflected from the first filter, receiving light of the second wavelength reflected from the second filter, and combining the received light of the first wavelength and the second wavelength into a single beam.

[0007] The first wavelength and the second wavelength are distinguished by a filter, thereby distinguishing the working wavelength from the non-working wavelength. The beam combining component combines the working wavelengths from different laser chips, thus filtering out the non-working wavelengths from the final output light and outputting a single beam. Attached Figure Description

[0008] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This is a schematic diagram of the connection relationship between optical communication terminals;

[0010] Figure 2 This is a schematic diagram of an optical network unit structure;

[0011] Figure 3 This is a schematic diagram of an optical module structure provided in an embodiment of this application;

[0012] Figure 4 This is a schematic diagram of the exploded structure of an optical module provided in an embodiment of this application;

[0013] Figure 5 A cross-sectional view of an optical module structure provided in an embodiment of this application;

[0014] Figure 6 This is a schematic diagram of the assembly structure of the optical transmitting submodule and the fiber optic socket provided in an embodiment of this application;

[0015] Figure 7 This is an exploded view of the optical emission submodule structure provided in an embodiment of this application;

[0016] Figure 8 This is a schematic diagram of the structure of an optical emission submodule provided in an embodiment of this application;

[0017] Figure 9 This is a schematic diagram of another optical emission submodule provided in an embodiment of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] One of the core aspects of optical communication is the conversion between optical and electrical signals. Optical communication uses optical signals carrying information to transmit information in information transmission equipment such as optical fibers / waveguides. The passive transmission characteristics of light in optical fibers / waveguides enable low-cost and low-loss information transmission. On the other hand, information processing equipment such as computers uses electrical signals. In order to establish an information connection between information transmission equipment such as optical fibers / waveguides and information processing equipment such as computers, it is necessary to realize the conversion between electrical and optical signals.

[0020] In the field of fiber optic communication technology, optical modules realize the mutual conversion between optical and electrical signals, which is the core function of optical modules. Optical modules achieve electrical connection with external host computers through gold fingers on their internal circuit boards. The main electrical connections include power supply, I2C signals, data signals, and grounding. The gold finger-based electrical connection method has become the mainstream connection method in the optical module industry. Based on this, the pin definitions on the gold fingers have formed various industry protocols / standards.

[0021] Figure 1 This is a schematic diagram illustrating the connection relationships between optical communication terminals. For example... Figure 1 As shown, 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.

[0022] One end of the optical fiber 101 is connected to the remote server, and one end of the network cable 103 is connected to the local information processing device. The connection between the local information processing device and the remote server is completed by the connection between the optical fiber 101 and the network cable 103. The connection between the optical fiber 101 and the network cable 103 is completed by the optical network unit 100 with the optical module 200.

[0023] The optical port of the optical module 200 is connected to the optical fiber 101, establishing a bidirectional optical signal connection. The electrical port of the optical module 200 is connected to the optical network unit 100, establishing a bidirectional electrical signal connection. The optical module realizes the mutual conversion between optical signals and electrical signals, thereby establishing a connection between the optical fiber 101 and the optical network unit 100.

[0024] Specifically, the optical signal from the optical fiber is converted into an electrical signal by the optical module and then input into the optical network unit 100. The electrical signal from the optical network unit 100 is converted into an optical signal by the optical module and then input into the optical fiber 101. The optical module 200 is a tool for realizing the conversion between photoelectric signals and electrical signals, but it does not have the function of processing data. In the above photoelectric conversion process, the carrier of information changes between light and electricity, but the information itself does not change.

[0025] The optical network unit 100 has an optical module interface 102 for connecting to the optical module 200 and establishing a bidirectional electrical signal connection with the optical module 200. The optical network unit also has a network cable interface 104 for connecting to a network cable 103 and establishing a bidirectional electrical signal connection with the network cable 103; the optical module 200 and the network cable 103 are connected through the optical network unit. Specifically, the optical network unit transmits signals from the optical module to the network cable and vice versa, acting as a host computer for the optical module to monitor its operation.

[0026] At this point, the remote server establishes a bidirectional signal transmission channel with the local information processing equipment via fiber optic cable 101, optical module 200, optical network unit 100, and network cable 103.

[0027] Common information processing equipment includes routers, switches, and computers; an optical network unit is the host computer of an optical module, which provides data signals to the optical module and receives data signals from the optical module. Other common host computers for optical modules include optical line terminals (OLTs).

[0028] Figure 2 This is a schematic diagram of an optical network unit structure. (Example:) Figure 2 As shown, the optical network unit 100 has a circuit board 105, and a cage 106 is provided on the surface of the circuit board 105; an electrical connector connected to the circuit board 105 is provided in the cage 106 for connecting to the electrical port of the optical module such as the gold finger; a heat sink 107 is provided on the cage 106, and the heat sink 107 has a fin-like protruding structure to increase the heat dissipation area.

[0029] The optical module 200 is inserted into the optical network unit 100, specifically by inserting the electrical port of the optical module into the electrical connector in the cage 106, and the optical port of the optical module is connected to the optical fiber 101.

[0030] The cage 106 is located on the circuit board 105 of the optical network unit 100, and encloses the electrical connector on the circuit board 105 in the cage; the optical module is inserted into the cage and fixed by the cage. The 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.

[0031] Figure 3 This is a schematic diagram of an optical module structure provided in an embodiment of this application. Figure 4 This is an exploded view of an optical module structure provided in an embodiment of this application, as shown below. Figure 3 , Figure 4 As shown, the optical module 200 provided in this embodiment of the invention includes an upper housing 201, a lower housing 202, an unlocking handle 203, a circuit board 300, an optical transmitting sub-module 400, an optical receiving sub-module 500, and an optical fiber socket 502.

[0032] The upper housing 201 and the lower housing 202 form a cavity with two ports, which can be two ports in the same direction (204, 205) or two ports in different directions; one port is an electrical port 204, used to insert into the host computer such as the optical network unit; the other port is an optical port 205, used to connect to the external optical fiber 101; the circuit board 300, the optical transmitting sub-module 400 and the optical receiving sub-module 500 and other optoelectronic devices are located in the cavity formed by the upper and lower housings.

[0033] The upper and lower housings are generally made of metal, which is beneficial for electromagnetic shielding and heat dissipation. The assembly method of combining the upper and lower housings makes it easy to install circuit boards and other components into the housing. The housing of the optical module is generally not made into a single structure, as this would make it difficult to install positioning components, heat dissipation and electromagnetic shielding structures when assembling circuit boards and other components, which is not conducive to production automation.

[0034] The unlocking handle 203 is located on the outer wall of the enclosure cavity / lower housing 202. Pulling the end of the unlocking handle allows the unlocking handle to move relative to the outer wall surface. When the optical module is inserted into the host computer, the unlocking handle 203 engages with the cage 106, thereby fixing the optical module in the host computer. By pulling the unlocking handle to release the engagement between the optical module 200 and the cage 106, the optical module can be pulled out of the host computer.

[0035] The circuit board 300 is located within a cavity formed by the upper housing and the outer shell. The circuit board 300 is electrically connected to the optical emitting sub-module 400 and the optical receiving sub-module 500, respectively. The circuit board is equipped with electrical components such as chips, capacitors, and resistors. Appropriate chips are selected based on product requirements. Common chips include microprocessors (MCUs), clock data recovery chips (CDRs), laser driver chips, transimpedance amplifier (TIA) chips, limiting amplifier (LA) chips, and power management chips. The transimpedance amplifier is closely related to the photodetector chip. Some products package the transimpedance amplifier and photodetector chip together, such as in the same TO tube or the same outer shell; alternatively, the photodetector chip and transimpedance amplifier can be packaged separately, with the transimpedance amplifier placed on the circuit board.

[0036] The chip on circuit board 300 can be a multi-functional integrated chip, such as integrating a laser driver chip and an MCU chip into one chip, or integrating a laser driver chip, a limiting amplifier chip, and an MCU chip into one chip. A chip is an integration of circuits, but the functions of each circuit do not disappear due to integration; only the circuit's form changes, and the chip still retains that circuit form. Therefore, having three independent chips—an MCU, a laser driver chip, and a limiting amplifier chip—on the circuit board is equivalent to having a single three-functional integrated chip on circuit board 300.

[0037] The end surface of the circuit board 300 has gold fingers, which are composed of independent pins. The circuit board is inserted into the electrical connector in the cage, and the gold fingers are connected to the snap-fit ​​spring in the electrical connector. Gold fingers can be set on only one side of the circuit board, but considering the large number of pins required, gold fingers are generally set on both the top and bottom surfaces of the circuit board. The gold fingers are used to establish an electrical connection with the host computer. The specific electrical connection can be power supply, grounding, I2C signal, communication data signal, etc.

[0038] An optical module also includes an optical transmitting sub-module and an optical receiving sub-module, which can be collectively referred to as an optical sub-module. For example... Figure 4 As shown, the optical module provided in this embodiment of the invention includes an optical emitting sub-module 400 and an optical receiving sub-module 500. The optical emitting sub-module 400 is located at the edge of the circuit board 300. The optical emitting sub-module 400 and the optical receiving sub-module 500 are staggered on the surface of the circuit board 300, which is beneficial to achieving a better electromagnetic shielding effect.

[0039] The optical emission submodule 400 is disposed on the surface of the circuit board 300. In another common packaging method, the optical emission submodule is physically separated from the circuit board and electrically connected through a flexible board. In this embodiment, the optical emission submodule 400 is connected to the first optical fiber socket 502 through the first optical fiber 501.

[0040] The optical emission submodule 400 is located within a cavity formed by upper and lower housings. For example... Figure 4 As shown, the circuit board 300 has a notch 301 for placing the light-emitting secondary module. The notch 301 can be located in the middle of the circuit board or at its edge. The light-emitting secondary module is embedded in the notch 301 of the circuit board, which facilitates the circuit board extending into the light-emitting secondary module and also facilitates fixing the light-emitting secondary module to the circuit board. Optionally, the light-emitting secondary module 400 can be fixedly supported by the lower housing 202.

[0041] The optical receiving submodule 500 is disposed on the surface of the circuit board 300. In another common packaging method, the optical receiving submodule is physically separated from the circuit board and electrically connected through a flexible board. In this embodiment, the optical receiving submodule 500 is connected to the second optical fiber socket 504 via the second optical fiber 503. The signal light from outside the optical module is transmitted through the external optical fiber to the second optical fiber socket 504 and then to the second optical fiber 503, and then through the second optical fiber 503 to the optical receiving submodule 500. The receiving submodule 500 converts the received signal light into a current signal.

[0042] Furthermore, the optical receiving sub-module 500 includes optical components and optoelectronic switching devices. The optical components include fiber optic adapters, arrayed waveguide gratings, lenses, etc. The second optical fiber 503 transmits the signal light to the optical components, then the optical components convert the signal light beam transmission path, and finally transmit it to the optoelectronic switching devices.

[0043] Figure 5 This is a cross-sectional view of an optical module structure provided in an embodiment of this application. For example... Figure 5 As shown, the optical module provided in this embodiment of the invention includes a lower housing 202, a circuit board 300, an optical transmitting sub-module 400, and an optical receiving sub-module 500. The optical transmitting sub-module 400 and the optical receiving sub-module 500 are located on the circuit board 300.

[0044] The first fiber optic socket 502 is connected to the optical transmitting sub-module 400 via the first fiber optic cable 501, and the second fiber optic socket 504 is connected to the optical receiving sub-module 500 via the second fiber optic cable 503. The following explanation uses the connection between the first fiber optic socket 502 and the optical transmitting sub-module 400 via the first fiber optic cable 501 as an example.

[0045] The lower housing 202 is used to support the circuit board 300 and the second fiber optic socket 502. The circuit board 300 supports the optical emission sub-module 400. Optionally, the lower housing 202 has a slot 206 with a gap 206a in it. The slot 206 may be formed by an upward protrusion on the surface of the lower housing.

[0046] The first fiber optic socket 502 includes a main body 502a and a protrusion 502b. The protrusion 502b is located on the surface of the main body 502a and protrudes relative to the main body. The first fiber optic socket 502 is assembled and fixed to the slot 206 on the lower housing 202. Specifically, the fiber optic socket is fixed to the lower housing by placing the protrusion 502b in the gap 206a of the slot 206. Furthermore, the structure and fixing method of the second fiber optic socket 504 are the same as those of the first fiber optic socket 502.

[0047] The slot 206 divides the lower housing into two areas. The circuit board 300 is located in one of these areas, and protrusions are formed on the surface of the lower housing in this area to fix the circuit board 300. The light-emitting secondary module 400 is fixed together with the circuit board 300. By fixing the circuit board 300, the light-emitting secondary module is fixed to the lower housing. Of course, the light-emitting secondary module can also be directly fixed to the lower housing without the need for indirect fixation through the circuit board 300.

[0048] The fiber optic socket is located in another area, and an external fiber optic plug extends into this other area to mate with the fiber optic socket. Thus, the circuit board 300 and the fiber optic socket are respectively fixed to the lower housing, meaning the positions of the optical transmitting sub-module 400 and the fiber optic socket 502 are relatively fixed. Consequently, the optical fiber 501a connecting the optical transmitting sub-module and the fiber optic socket needs to have specific dimensions.

[0049] Figure 6 This is a schematic diagram of an assembly structure of an optical transmitting submodule and an optical fiber socket provided in an embodiment of this application. Figure 6 As shown, the optical transmission sub-module 400 is connected to the first optical fiber socket 502 via the optical fiber adapter 600 and the first optical fiber 501. One end of the first optical fiber 501 is connected to the optical fiber adapter 600, and the other end is connected to the first optical fiber socket 502.

[0050] The fiber optic adapter 600 is used to be inserted into the optical emission sub-module to receive the light focused by the optical lens; the first fiber optic socket 502 is connected to the first fiber optic 501 and the fiber optic plug outside the optical module respectively, so as to realize the optical connection between the inside and outside of the optical module, thereby forming that the light of the optical emission sub-module enters the fiber optic through the fiber optic adapter, is transmitted to the first fiber optic socket 502 by the fiber optic, and is transmitted to the outside of the optical module by the first fiber optic socket 502.

[0051] Figure 7 This is an exploded view of an optical emission submodule structure provided in an embodiment of this application. For example... Figure 7 As shown in the embodiment of this application, the optical emitting sub-module is provided with a laser component 404, which includes a laser chip 404a, a collimating lens 404b, a metallized ceramic 404c, and a semiconductor cooler 404d. The most common optical emitting chip in optical modules is the laser chip. The laser chip 404a is disposed on the surface of the metallized ceramic 404c, and a circuit pattern is formed on the surface of the metallized ceramic 404c, which can supply power to the laser chip. Simultaneously, the metallized ceramic 404c has excellent thermal conductivity and can serve as a heat sink for dissipating heat from the laser chip 404a. Lasers, with their superior single-wavelength characteristics and excellent wavelength tuning characteristics, are the preferred light source for optical modules and even fiber optic transmission. Other types of light, such as LED light, are generally not used in common optical communication systems. Even if such light sources are used in special optical communication systems, their characteristics and chip structures differ significantly from lasers, resulting in significant technical differences between optical modules using lasers and those using other light sources. Those skilled in the art generally do not believe that these two types of optical modules can mutually provide technical inspiration.

[0052] The function of an optical lens is to converge light. Light emitted from a light-emitting chip is in a divergent state, and convergence processing is required to facilitate subsequent optical path design and optical coupling into the optical fiber. Common convergence methods include converging divergent light into parallel light, and converging divergent and parallel light into convergent light. Figure 7 The image shows a collimating lens 404b and a focusing lens 407. The collimating lens 404b is disposed in the light output path of the laser chip to converge the diverging light of the laser chip into parallel light. The focusing lens 407 is disposed on the side near the fiber optic adapter 600 to converge the parallel light into the fiber optic adapter 600.

[0053] Depending on the transmission design and the characteristics of the laser chip, the optical emission submodule may also include a semiconductor cooler TEC404d. The TEC404d is disposed directly or indirectly on the bottom surface of the optical emission submodule cavity, and metallized ceramic is disposed on the surface of the TEC404d. The TEC404d is used to balance heat to maintain the set operating temperature of the laser chip.

[0054] The optical emission sub-module has a packaging structure to encapsulate the laser chip and other components. Existing packaging structures include coaxial TO-CAN packaging, silicon photonics packaging, on-board lens assembly packaging (COB-LENS), and micro-optics XMD packaging. Packaging is also divided into hermetic packaging and non-hermetic packaging. Packaging provides a stable and reliable operating environment for the laser chip and forms external electrical connections and optical output.

[0055] Depending on the product design and manufacturing process, optical modules will employ different packages to create optical emitting sub-modules. Laser chips can have vertical-cavity surface emission (VCSEL) or edge emission, and the different emission directions of the laser chip will also affect the choice of package form. There are significant technical differences between various packages; both in terms of structure and manufacturing process, they represent different technological directions. Those skilled in the art understand that although different packages may achieve certain similarities in purpose, they belong to different technological routes, and different packaging technologies do not provide each other with technological inspiration.

[0056] like Figure 6 , Figure 7As shown, the optical emission sub-module 400 provided in this embodiment of the application further includes a cover plate 401 and an optical emission sub-module cavity (hereinafter referred to as cavity) 402. The cover plate 401 covers the cavity 402 from above. One side wall of the cavity 402 has an opening 403 for inserting a circuit board 300. The circuit board 300 is fixed to the lower housing of the optical module. A laser component 404 is disposed in the cavity 402. The circuit board 300 extending into the cavity is electrically connected to the laser component 404. The laser component has a laser chip and may also include components such as a collimating lens to form collimated light emission. In some optical modules, an optical multiplexing component is disposed in the cavity 402. The optical multiplexing component combines the light from the laser component 404 into a single beam of light, so that the single beam of light includes light of different wavelengths. The other side wall of the cavity 402 has a through hole 406, into which the single beam of light combined by the optical multiplexing component enters. A focusing lens 407 can also be disposed between the through-hole 406 and the optical multiplexing component to focus the light for subsequent coupling. The fiber optic adapter 600 extends into the through-hole 406 to couple and receive light from the optical multiplexing component. The tail of the fiber optic adapter is connected to the first fiber optic socket 502 via the first fiber optic cable 501. The light received by the fiber optic adapter 600 is transmitted to the first fiber optic socket 502 via the first fiber optic cable 501.

[0057] During use, it was discovered that when any laser chip is turned on or off, it generates light of a non-operating wavelength. When this non-operating wavelength light has the same wavelength as the signal light generated by other laser chips, it will cause chirp crosstalk to the signal light generated by that laser chip. To avoid chirp crosstalk caused by non-operating wavelength light generated when a laser chip is turned on or off, the optical emission sub-module 400 provided in this application embodiment further includes a multiplexing component, a first filter, and a second filter, etc., which are disposed in the cavity 402. In this application embodiment, the bandpass filtering effect of the first and second filters is used to ensure that the light of the operating wavelength and the non-operating wavelength are directed in different directions; the multiplexing component combines the light of the operating wavelengths from different laser chips, thereby filtering out the non-operating wavelength light in the final output light, resulting in a single-beam output.

[0058] The optical module provided in this application includes a first laser chip electrically connected to the circuit board, capable of emitting light of a first wavelength and a second wavelength; a first filter receiving light emitted by the first laser chip, capable of reflecting light of the first wavelength and transmitting light of the second wavelength; a second laser chip electrically connected to the circuit board, capable of emitting light of the first wavelength and the second wavelength; a second filter receiving light emitted by the second laser chip, capable of reflecting light of the second wavelength and transmitting light of the first wavelength; and a beam combiner capable of receiving light of the first wavelength reflected from the first filter, receiving light of the second wavelength reflected from the second filter, and combining the received light of the first wavelength and the second wavelength into a single beam.

[0059] The first wavelength is the operating wavelength of the first laser chip; the second wavelength is the operating wavelength of the second laser chip. The light emitted by the first laser chip and the second laser chip has overlapping wavelengths.

[0060] The beam combiner utilizes the principle of light polarization to combine light beams. It includes a first polarizer, one side of which can receive light of a first wavelength and a first polarization state; the other side of which can receive light of a second wavelength and a second polarization state; the first polarizer can transmit light of the first polarization state and reflect light of the second polarization state, so as to combine the light of the first wavelength and the light of the second wavelength.

[0061] Light with different polarization states can be obtained using a polarization state changing device. When light passes through the polarization state changing device, the polarization state of the light will change regularly. Using this principle, combined with the polarization state of the light before it enters the polarization state changing device, we can know the polarization state of the light after it passes through the polarization state changing device.

[0062] The light emitted by the first laser chip and the second laser chip can be in the same polarization state or in different polarization states. When the light emitted by the first laser chip and the second laser chip has the same polarization state, after passing through the first polarization state changing device and the second polarization state changing device respectively, the polarization states of the two beams are still the same, and they cannot be combined using the difference in polarization states. Therefore, the wave combining component also includes a third polarization state changing device, which works in conjunction with the first polarization state changing device to change the polarization state of the light from the first laser chip again, resulting in two beams with different polarization states, which can then be combined using the difference in polarization states.

[0063] The light emitted by the first laser chip and the second laser chip can have different polarization states. After passing through the first polarization state changing device and the second polarization state changing device respectively, the polarization states of the two beams are still different. The difference in polarization states can be used to combine the beams, and there is no need to use the third polarization state changing device.

[0064] The technical solution provided in this application will be described in detail below with specific examples.

[0065] Figure 8 This is a schematic diagram of the structure of an optical emission submodule provided in an embodiment of this application. Figure 8 As shown, the optical emission sub-module provided in this embodiment includes a first laser chip 404a1 and a second laser chip 404a2, as well as a beam splitter 405, a first filter 4054, and a second filter 4057. Specifically: when the first laser chip 404a1 is working normally, it generates a first wavelength signal light, denoted as first wavelength signal light λ1; when the first laser chip 404a1 is off and on, it generates a second wavelength light, denoted as second wavelength light λ2. Similarly, when the second laser chip 404a2 is working normally, it generates a second wavelength signal light, denoted as second wavelength signal light λ2; when the first laser chip 404a1 is off and on, it generates a first wavelength light, denoted as first wavelength light λ1. The first filter 4054 filters out the second wavelength light λ2, and the second filter 4057 filters out the first wavelength light λ1. The beam splitter assembly 405, the first filter 4054, and the second filter 4057 are combined to ensure that the second wavelength light λ2 generated by the first laser chip 404a1 when it is turned off and on is leaked through the first filter 4054 without causing crosstalk to the second wavelength signal light λ2 generated by the second laser chip 404a2 when it is working, and that the first wavelength light λ1 generated by the second laser chip 404a2 when it is turned off and on is leaked through the second filter 4057 without causing crosstalk to the first wavelength signal light λ1 generated by the first laser chip 404a1 when it is working. This avoids chirp crosstalk between laser chips 404a in the optical module when the laser chips 404a are turned on or off.

[0066] In this embodiment, the beam splitting assembly 405 includes a first polarization beam splitter 4051, a third polarization state changing device 4052, a first polarization state changing device 4053, a second polarization beam splitter 4055, and a second polarization state changing device 4056. The third polarization state changing device 4052, the first polarization state changing device 4053, and the second polarization state changing device 4056 cooperate with the beam combiner to realize the optical path. Specifically: a first polarization beam splitter 4051 is disposed in the output optical path of the first laser chip 404a1; a first polarization state changing device 4053 and a first filter 4054 are sequentially disposed in the transmission optical path of the first polarization beam splitter 4051; a third polarization state changing device 4052 is disposed in the reflection optical path of the first polarization beam splitter 4051; a second polarization beam splitter 4055 is disposed in the output optical path of the second laser chip 404a2, and the reflection optical path of the second polarization beam splitter 4055 reflects the signal light of the second laser chip 404a2 at a specified operating wavelength and transmits the signal light of the first laser chip 404a1 at a specified operating wavelength; a second polarization state changing device 4056 and a second filter 4057 are sequentially disposed in the transmission optical path of the second polarization beam splitter 4055.

[0067] like Figure 8As shown, the light generated by the first laser chip 404a1 during its off, on, and normal operation is linearly polarized, with the polarization direction parallel to the plane of the paper (double-headed arrows in the figure); the light generated by the second laser chip 404a2 during its off, on, and normal operation is also linearly polarized, with the polarization direction parallel to the plane of the paper (double-headed arrows in the figure). The first wavelength signal light λ1 is incident on the first polarization beam splitter 4051 along the output optical path of the first laser chip 404a1 and passes through the first polarization beam splitter 4051. It then travels along the transmission optical path of the first polarization beam splitter 4051 to the first polarization state changing device 4053, and then through the first polarization state changing device 4053 to the first filter 4054. Since the first filter 4054 filters out the second wavelength light λ2, the first wavelength signal light λ1 is reflected back to the first polarization state changing device 4053 by the first filter 4054. The first wavelength signal light λ1 then passes through the first polarization state changing device 4053 again and is re-incidentally incident on the first polarization beam splitter 4051. The first wavelength signal light λ1 is transmitted twice... The polarization direction of the first wavelength signal light, which passes through the first polarization state changing device 4053 for the first time, is rotated by 90°, meaning its polarization direction is perpendicular to the plane of the paper (as shown in the figure). The first wavelength signal light λ1, which is then re-injected into the first polarization beamsplitter 4051, will propagate along the reflected light path of the first polarization beamsplitter 4051 to the third polarization state changing device 4052. The third polarization state changing device 4052 will again change the polarization direction by 90°, making it parallel to the plane of the paper. It will then be incident on the second polarization beamsplitter 4055, and finally transmitted through the second polarization beamsplitter 4055 and output along its reflected light path. Meanwhile, the second wavelength light λ2, along the output light path of the first laser chip 404a1, is incident on the first polarization beamsplitter 4051 and propagates along its transmission light path to the first polarization state changing device 4053, before being transmitted out through the first filter 4054. In this embodiment, the first polarization beam splitter 4051, together with the first polarization state changing device 4053 and the first filter 4054, separates the transmission optical paths of the first wavelength signal light λ1 and the second wavelength light λ2, so that the second wavelength light λ2 does not transmit along the optical path of the first wavelength signal light λ1. Therefore, the second wavelength light λ2 will not enter the output optical path of the optical emission sub-module, and thus the second wavelength light λ2 will not cause crosstalk to the second wavelength signal light λ2.

[0068] The second wavelength signal light λ2 is incident on the second polarization beam splitter 4055 along the output optical path of the second laser chip 404a2, and then transmitted to the second polarization state changing device 4056 along the transmission optical path of the second polarization beam splitter 4055. After being transmitted to the second filter 4057 via the second polarization state changing device 4056, the second wavelength signal light λ2 is reflected back to the second polarization state changing device 4056 by the second filter 4057. The second wavelength signal light λ2 is then re-incident on the second polarization beam splitter 4055 after passing through the second polarization state changing device 4056 twice. Compared with the second wavelength signal light that passed through the second polarization state changing device 4056 for the first time, the polarization direction of the second wavelength signal light λ2 has rotated by 90°, that is, the polarization direction is perpendicular to the plane of the paper. The second wavelength signal light that is re-incident on the second polarization beam splitter 4055 is then transmitted and output along the reflection optical path of the second polarization beam splitter 4055. The first wavelength light λ1 is incident on the second polarization beam splitter 4055 along the output optical path of the second laser chip 404a2 and propagates along the transmission optical path of the second polarization beam splitter 4055 to the second polarization state changing device 4056, and then is transmitted out through the second filter 4057. In this embodiment, the second polarization beam splitter 4055, in combination with the second polarization state changing device 4056 and the second filter 4057, separates the transmission of the second wavelength signal light λ2 and the first wavelength light λ1, so that the first wavelength light λ1 does not propagate along the optical path of the second wavelength signal light λ2. Therefore, the first wavelength light λ1 will not enter the output optical path of the optical emission submodule, and thus the first wavelength light λ1 will not cause crosstalk to the first wavelength signal light λ1.

[0069] Furthermore, such as Figure 8As shown, the first polarization beam splitter 4051 includes a second polarizer 0511 and a second polarization beam splitting prism 0512; a first polarization state changing device 4053 and a first filter 4054 are sequentially disposed in the transmission optical path of the second polarizer 0511; a third polarization state changing device 4052 is disposed in the reflection optical path of the second polarization beam splitting prism 0512. A first wavelength signal light λ1 and a second wavelength light λ2 are incident on the second polarizer 0511 along the output optical path of the first laser chip 404a1. Since the polarization directions of the first wavelength signal light λ1 and the second wavelength light λ2 are both parallel to the plane of the paper, the first wavelength signal light λ1 and the second wavelength light λ2 transmitted to the polarization beam splitting medium film of the second polarizer 0511 pass through the polarization beam splitting medium film; the first wavelength signal light λ1, after being reflected again by the first filter 4054 and transmitted through the first polarization state changing device 4053, is polarized... The polarization direction has changed, and the polarization direction is perpendicular to the paper. When it is transmitted to the polarization beam-splitting medium film of the second polarizer 0511 again, it will be reflected by the polarization beam-splitting medium film of the second polarizer 0511 and transmitted to the second polarization beam-splitting prism 0512. When it is transmitted to the polarization beam-splitting medium film of the second polarization beam-splitting prism 0512, since the polarization direction is perpendicular to the paper, the first wavelength signal light λ1 will be reflected by the polarization beam-splitting medium film of the second polarization beam-splitting prism 0512 and then transmitted to the third polarization state changing device 4052.

[0070] Alternatively, a first reflecting surface 0512A can be provided between the second polarizer and the first polarizer to replace the polarization beam splitter film, which can reflect the light from the second polarizer toward the first polarizer. When a third polarization state changing device is present, the first reflecting surface can be provided between the second polarizer and the third polarization state changing device, or between the first polarizer and the third polarization state changing device.

[0071] Furthermore, such as Figure 8As shown, the second polarization beam splitter 4055 includes a third polarizer 0551; a second polarization state changing device 4056 and a second filter 4057 are sequentially disposed in the transmission optical path of the third polarizer 0551; and a first polarizer 0552 is disposed in the output optical path of the third polarization state changing device 4052. The second wavelength signal light λ2 and the first wavelength light λ1 are incident on the third polarizer 0551 along the output optical path of the second laser chip 404a2. Since the polarization directions of the second wavelength signal light λ2 and the first wavelength light λ1 are both parallel to the paper, the second wavelength signal light λ2 and the first wavelength light λ1 are transmitted to the polarization beam splitting medium film of the third polarizer 0551 and pass through the polarization beam splitting medium film. The second wavelength signal light λ2, after being reflected by the second filter 4056 and passing through the second polarization state changing device 4056 again, has a changed polarization direction that is perpendicular to the paper. When it is transmitted to the polarization beam splitting medium film of the third polarizer 0551 again, it will be reflected by the polarization beam splitting medium film of the third polarizer 0551 and transmitted to the first polarizer 0552. When it is transmitted to the polarization beam splitting medium film of the first polarizer 0552, since the polarization direction is perpendicular to the paper, the second wavelength signal light λ2 will be reflected by the polarization beam splitting medium film of the first polarizer 0552 and then output from the first polarizer 0552. The polarization direction of the first wavelength signal light λ1 transmitted through the third polarization state changing device 4052 is deflected by 90°, making it perpendicular to the plane of the paper. When the first wavelength signal light λ1 is transmitted to the polarization beam splitter film of the first polarizer 0552, it passes through the polarization beam splitter film and is then output from the first polarizer 0552. Finally, the first wavelength signal light λ1 and the second wavelength signal light λ2 are combined, without any mixing of the second wavelength light λ2 or the first wavelength light λ1, thus preventing crosstalk between the first wavelength signal light λ1 and the second wavelength signal light λ2.

[0072] Furthermore, such as Figure 8 As shown, the optical emission sub-module 400 provided in this embodiment of the application also includes a Faraday rotator 4058. The Faraday rotator 4057 is disposed at the output end of the reflected optical path of the second polarization beam splitter 4055, and the Faraday rotator 4058 has an optical isolation function. Specifically, when the polarization directions of the first wavelength signal light λ1 and the second wavelength signal light λ2 change after passing through the Faraday rotator 4057, and if they are reflected back to the Faraday rotator 4057, the polarization directions of the first wavelength signal light λ1 and the second wavelength signal light λ2 will change again, effectively preventing the first wavelength signal light λ1 from returning to the first laser chip 404a1 along its original path and the second wavelength signal light λ2 from returning to the second laser chip 404a2 along its original path.

[0073] exist Figure 8In the optical emission sub-module provided in the illustrated embodiment, the positions of the first laser chip 404a1 and the second laser chip 404a2 are merely examples, and their positions are not limited to those of the first laser chip 404a1 and the second laser chip 404a2. Figure 8 The structure shown can also be transformed into other forms or structures.

[0074] Figure 9 This is a schematic diagram of another optical emission submodule provided in an embodiment of this application. Figure 8 The optical emission sub-module provided in the Chinese embodiment is the same. Figure 9 In the embodiment shown, the first laser chip 404a1 and the second laser chip 404a2 of the optical emission sub-module also include a beam splitting component 405, a first filter 4054 and a second filter 4057.

[0075] In this embodiment, the beam splitting assembly 405 includes a first polarization beam splitter 4051, a third polarization state changing device 4052, a first polarization state changing device 4053, a second polarization beam splitter 4055, and a second polarization state changing device 4056. The third polarization state changing device 4052, the first polarization state changing device 4053, and the second polarization state changing device 4056 are used as a beam combiner assembly. Specifically: a first polarization beam splitter 4051 is disposed in the output optical path of the first laser chip 404a1; a first polarization state changing device 4053 and a first filter 4054 are sequentially disposed in the transmission optical path of the first polarization beam splitter 4051; a third polarization state changing device 4052 is disposed in the output optical path of the second laser chip 404a2; a second polarization beam splitter 4055 is disposed in the output optical path of the third polarization state changing device 4052, and the second polarization beam splitter 4055 is disposed in the reflection optical path of the first polarization beam splitter 4051; a second polarization state changing device 4056 and a second filter 4057 are sequentially disposed in the reflection optical path of the first polarization beam splitter 4051.

[0076] like Figure 9As shown, the first wavelength signal light λ1 is incident on the first polarization beam splitter 4051 along the output optical path of the first laser chip 404a1 and passes through the first polarization beam splitter 4051. Then, it is transmitted along the transmission optical path of the first polarization beam splitter 4051 to the first polarization state changing device 4053, and then transmitted through the first polarization state changing device 4053 to the first filter 4054. Since the first filter 4054 is used to filter out the second wavelength light λ2, the first wavelength signal light λ1 is reflected back to the first polarization state changing device 4053 by the first filter 4054. The signal light λ1 passes through the first polarization state changing device 4053 again and is re-injected into the first polarization beam splitter 4051. The polarization direction of the first wavelength signal light λ1, after passing through the first polarization state changing device 4053 twice, has rotated by 90° compared to the first time it passed through the device, meaning its polarization direction is perpendicular to the plane of the paper. Therefore, the first wavelength signal light λ1 re-injected into the first polarization beam splitter 4051 will propagate along the reflected light path of the first polarization beam splitter 4051 and be output. Meanwhile, the second wavelength light λ2 is incident into the first polarization beam splitter 4051 along the output light path of the first laser chip 404a1 and propagates along the transmission light path of the first polarization beam splitter 4051 to the first polarization state changing device 4053, and then is transmitted out through the first filter 4054. In this embodiment, the first polarization beam splitter 4051, together with the first polarization state changing device 4053 and the first filter 4054, separates the transmission optical paths of the first wavelength signal light λ1 and the second wavelength light λ2, so that the second wavelength light λ2 does not transmit along the optical path of the first wavelength signal light λ1. Therefore, the second wavelength light λ2 will not enter the output optical path of the optical emission sub-module, and thus the second wavelength light λ2 will not cause crosstalk to the second wavelength signal light λ2.

[0077] The second wavelength signal light λ2 is incident on the third polarization state changing device 4052 along the output optical path of the second laser chip 404a2. The polarization direction of the second wavelength signal light λ2 changes by 90° after passing through the third polarization state changing device 4052, that is, the polarization direction of the second wavelength signal light λ2 becomes perpendicular to the paper plane after passing through the third polarization state changing device 4052. The second wavelength signal light λ2, after passing through the third polarization state changing device 4052, is incident on the second polarization beam splitter 4055 and transmitted along the reflected optical path of the second polarization beam splitter 4055 to the second polarization state changing device 4056, and then transmitted through the second polarization state changing device 4056 to the second filter 4057. Since the second filter 4057 is used to filter out the first wavelength light λ1... Therefore, the second wavelength signal light λ2 is reflected back to the second polarization state changing device 4056 by the second filter 4057. The second wavelength signal light λ2 passes through the second polarization state changing device again and is re-injected into the second polarization beam splitter 4055. The polarization direction of the second wavelength signal light λ2 after passing through the second polarization state changing device 4056 twice is rotated by 90° compared to the second wavelength signal light that passed through the second polarization state changing device 4056 for the first time. That is, the polarization direction is perpendicular to the plane of the paper. The second wavelength signal light that is re-injected into the second polarization beam splitter 4055 is transmitted along the transmission optical path of the second polarization beam splitter 4055 and then to the first polarization beam splitter 4051. Finally, it is output along the reflection optical path of the first polarization beam splitter 4051. The first wavelength light λ1 is incident on the third polarization state changing device 4052 along the output optical path of the second laser chip 404a2. The polarization direction of the first wavelength light λ1 changes by 90° after passing through the third polarization state changing device 4052, that is, the polarization direction of the first wavelength light λ1 is converted to be perpendicular to the paper plane after passing through the third polarization state changing device 4052. The first wavelength light λ1 passing through the third polarization state changing device 4052 is incident on the second polarization beam splitter 4055 and transmitted along the reflected optical path of the second polarization beam splitter 4055 to the second polarization state changing device 4056. After passing through the second polarization state changing device 4056, it is transmitted to the second filter 4057 and then transmitted out of the second filter 4057. In this embodiment, the second polarization beam splitter 4055, in conjunction with the third polarization state changing device 4052, the second polarization state changing device 4056, the second filter 4057, and the first polarization beam splitter 4051, separates the transmission of the second wavelength signal light λ2 and the first wavelength light λ1, so that the first wavelength light λ1 does not propagate along the optical path of the second wavelength signal light λ2. Therefore, the first wavelength light λ1 will not enter the output optical path of the optical emission submodule, and thus the first wavelength light λ1 will not cause crosstalk to the first wavelength signal light λ1.

[0078] Furthermore, such as Figure 9As shown, a second polarizer 0511 and a reflecting prism 0513 are arranged in sequence on the transmission light path of the second polarizer 0511; a first polarization state changing device 4053 and a first filter 4054 are arranged in sequence on the reflection light path of the second polarizer 0511; and a reflecting prism 0513 is arranged on the reflection light path of the second polarizer 0511. The first wavelength signal light λ1 and the second wavelength light λ2 are incident on the second polarizer 0511 along the output optical path of the first laser chip 404a1. Since the polarization directions of the first wavelength signal light λ1 and the second wavelength light λ2 are both parallel to the paper, the first wavelength signal light λ1 and the second wavelength light λ2 transmitted to the polarization beam splitting medium film of the second polarizer 0511 pass through the polarization beam splitting medium film. The first wavelength signal light λ1, which is reflected again by the first filter 4054 and transmitted through the first polarization state changing device 4053, has changed its polarization direction and is now perpendicular to the paper. When it is transmitted to the polarization beam splitting medium film of the second polarizer 0511 again, it will be reflected by the polarization beam splitting medium film of the second polarizer 0511 and transmitted to the reflecting prism 0513. When the first wavelength signal light λ1 is transmitted to the reflecting film of the reflecting prism 0513, it will be reflected and output.

[0079] Furthermore, such as Figure 9As shown, the second polarization beam splitter 4055 includes a third polarizer 0551; the third polarizer 0551 is disposed on the output optical path of the third polarization state changing device 4052, located on the reflected optical path of the first polarization beam splitter 4051; the second polarization state changing device 4056 and the second filter 4057 are sequentially disposed on the reflected optical path of the third polarizer 0551. The second wavelength signal light λ2 and the first wavelength light λ1 are incident on the third polarization state changing device 4052 along the output optical path of the second laser chip 404a2. After the polarization direction is changed by the third polarization state changing device 4052, they are incident on the third polarizer 0551. Since the polarization directions of the second wavelength signal light λ2 and the first wavelength light λ1 are both perpendicular to the plane of the paper, the second wavelength signal light λ2 and the first wavelength light λ1, which are transmitted to the polarization beam splitting medium film of the third polarizer 0551, are reflected by the polarization beam splitting medium film of the third polarizer 0551 and then pass through the second filter 4056. The second wavelength signal light λ2, reflected and re-transmitted through the second polarization state changing device 4056, has its polarization direction changed to be parallel to the plane of the paper. When it is transmitted again to the polarization beam-splitting medium film of the third polarizer 0551, it will be transmitted through the polarization beam-splitting medium film of the third polarizer 0551 and then to the second polarizer 0511, and then through the polarization beam-splitting medium film of the second polarizer 0511 to the reflecting prism 0513. When the second wavelength signal light λ2 is transmitted to the reflecting film of the reflecting prism 0513, it will be reflected and output. Finally, the first wavelength signal light λ1 and the second wavelength signal light λ2 are combined, without the second wavelength light λ2 or the first wavelength light λ1 being mixed in, thus preventing crosstalk between the first wavelength signal light λ1 and the second wavelength signal light λ2 caused by the first wavelength light λ1 and the second wavelength light λ2.

[0080] Furthermore, such as Figure 9 As shown, the optical emission sub-module 400 provided in this embodiment of the application also includes a Faraday rotator 4058. The Faraday rotator 4057 is disposed at the output end of the reflected optical path of the second polarization beam splitter 4055, and the Faraday rotator 4058 has an optical isolation function.

[0081] exist Figure 9 In the optical emission sub-module provided in the illustrated embodiment, the positions of the first laser chip 404a1 and the second laser chip 404a2 are merely examples, and their positions are not limited to those of the first laser chip 404a1 and the second laser chip 404a2. Figure 8 The structure shown can also be transformed in other forms or structures. For example, the positions of the first laser chip 404a1 and the second laser chip 404a2 can be swapped.

[0082] In the optical module provided by this application embodiment, the second wavelength light generated by the first laser chip 404a1 when it is turned off and on is leaked out through the first filter without causing crosstalk to the second wavelength signal light generated by the second laser chip 404a2 when it is working. Similarly, the first wavelength light generated by the second laser chip 404a2 when it is turned off and on is leaked out through the second filter without causing crosstalk to the first wavelength signal light generated by the first laser chip 404a1 when it is working. This avoids chirp crosstalk between laser chips when they are turned on or off in the optical module. Furthermore, when the number of laser chips in the optical module is greater than a certain amount, adjusting the structure of the beam splitter assembly and the position and number of narrowband filters can effectively prevent chirp crosstalk between laser chips.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optical module, characterized in that, Including circuit boards; The first laser chip is electrically connected to the circuit board and is capable of emitting light of a first wavelength and a second wavelength. The first wavelength light is the operating wavelength light of the first laser chip, and the second wavelength light is the non-operating wavelength light of the first laser chip. The first polarization state changing device transmits light of the first wavelength and the second wavelength. The first filter receives light transmitted by the first polarization state changing device and is capable of reflecting light of the first wavelength and transmitting light of the second wavelength; the first polarization state changing device changes the polarization state of the reflected light of the first wavelength. The second laser chip is electrically connected to the circuit board and is capable of emitting light of the first wavelength and the second wavelength. The light of the first wavelength is the non-operating wavelength light of the second laser chip, and the light of the second wavelength is the operating wavelength light of the second laser chip. The second polarization state changing device transmits light of the first wavelength and the second wavelength. The second filter receives light transmitted by the second polarization state changing device and is capable of reflecting light of the second wavelength and transmitting light of the first wavelength. The second polarization state changing device changes the polarization state of the reflected light of the second wavelength; The beam combiner is capable of receiving light of a first wavelength from the first polarization state changing device, receiving light of a second wavelength from the second polarization state changing device, and combining the received light of the first wavelength and the second wavelength into a single beam.

2. The optical module as described in claim 1, characterized in that, It includes a first polarization state changing device, which is capable of receiving light of a first wavelength reflected from the first filter and changing the light of the first wavelength to a first polarization state; The second polarization state changing device is capable of receiving light of a second wavelength reflected from the second filter and changing the light of the second wavelength to a second polarization state. A beam combiner includes a first polarizer, one side of which can receive light of a first wavelength and a first polarization state; the other side of which can receive light of a second wavelength and a second polarization state; the first polarizer can transmit light of the first polarization state and reflect light of the second polarization state, so as to achieve beam combining of light of the first wavelength and light of the second wavelength.

3. The optical module as described in claim 2, characterized in that, It includes a second polarizer, which is disposed between the first laser chip and the first polarization state changing device, and is capable of transmitting light emitted by the first laser chip and reflecting light of the first wavelength and first polarization state; The third polarizer is disposed between the second laser chip and the second polarization state changing device. It can transmit light emitted by the second laser chip and reflect light of the second wavelength and second polarization state. The first reflecting surface is disposed between the second polarizer and the first polarizer, and is capable of reflecting the light from the second polarizer toward the first polarizer.

4. The optical module as described in claim 1, characterized in that, It includes a first polarization state changing device, which is capable of receiving light of a first wavelength reflected from the first filter and changing the light of the first wavelength to a second polarization state; The second polarization state changing device is capable of receiving light of a second wavelength reflected from the second filter and changing the light of the second wavelength to a second polarization state. The third polarization state changing device is capable of changing light with a first wavelength and a second polarization state to a first polarization state. A beam combiner includes a first polarizer, one side of which can receive light of a first wavelength and a first polarization state; the other side of which can receive light of a second wavelength and a second polarization state; the first polarizer can transmit light of the first polarization state and reflect light of the second polarization state, so as to achieve beam combining of light of the first wavelength and light of the second wavelength.

5. The optical module as described in claim 4, characterized in that, It includes a second polarizer, which is disposed between the first laser chip and the first polarization state changing device, and is capable of transmitting light emitted by the first laser chip and reflecting light of the first wavelength and first polarization state; The third polarizer is disposed between the second laser chip and the second polarization state changing device. It can transmit light emitted by the second laser chip and reflect light of the second wavelength and second polarization state. A third polarization state changing device is disposed between the first polarizer and the second polarizer; A first reflecting surface is disposed between the second polarizer and the third polarization state changing device, or between the first polarizer and the third polarization state changing device; capable of reflecting the light from the second polarizer toward the first polarizer.

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