Polarization rotation beam splitter, optical chip and optical module

Abstract

The invention provides a polarization rotation beam splitter, an optical chip and an optical module, and the polarization rotation beam splitter comprises a mode conversion part which comprises a first waveguide and a second waveguide; one end of the connecting part is connected with the other end of the first waveguide, and the width of one end of the connecting part is larger than that of the other end; the mode coupling part comprises a first coupling waveguide and a second coupling waveguide, and the second coupling waveguide is located on the side edge of the first coupling waveguide and is spaced from the first coupling waveguide; one end of the first coupling waveguide is connected with the other end of the connecting part; the beam splitting part comprises a third waveguide and a fourth waveguide, one end of the third waveguide is connected with one end of the first coupling waveguide, one end of the fourth waveguide is connected with the other end of the second coupling waveguide, and a gap is formed between the third waveguide and the fourth waveguide. According to the polarization rotation beam splitter provided by the invention, deflection beam splitting of polarization multiplexing light beams can be realized, multiplexing of optical fibers and the like in an optical module can be conveniently adapted, and the requirement of high bandwidth of the optical module can be conveniently adapted.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of optical communication technology, and in particular to a polarization rotation beam splitter, an optical chip and an optical module. BACKGROUND

[0002] With the development of new business and application modes such as cloud computing, mobile Internet, video, etc., the progress of optical communication technology becomes increasingly important. In optical communication technology, an optical module, as one of the key devices in optical communication equipment, can realize optical-electrical signal conversion.

[0003] In optical communication, polarization multiplexing technology is used, two orthogonal polarization states can be used to carry different information to further improve the communication capacity. Therefore, optical polarization multiplexing technology expands the development path of on-chip optical communication. The polarization rotation beam splitter is an important part of realizing optical polarization multiplexing technology. SUMMARY

[0004] The polarization rotation beam splitter, the optical chip and the optical module provided by the present disclosure are convenient for adapting to the high-bandwidth requirement of the optical module.

[0005] In a first aspect, the present disclosure provides a polarization rotation beam splitter, comprising:

[0006] a substrate;

[0007] a beam splitting waveguide layer arranged above the substrate and used for splitting light;

[0008] a cladding layer wrapped around the side of the beam splitting waveguide layer;

[0009] The beam splitting waveguide layer comprises:

[0010] a mode conversion part comprising a first waveguide and a second waveguide, the second waveguide is arranged above the first waveguide and the bottom of the second waveguide is connected to the top of the first waveguide, the thickness of the second waveguide is greater than the thickness of the first waveguide; the width of one end of the second waveguide is greater than the width of the other end of the second waveguide, the width of one end of the second waveguide is greater than or equal to the width of one end of the first waveguide, and the width of the other end of the first waveguide is greater than the width of the other end of the second waveguide;

[0011] a connecting part connected to the other end of the first waveguide, the width of one end of the connecting part is greater than the width of the other end of the connecting part;

[0012] A mode coupling section includes a first coupling waveguide and a second coupling waveguide, the second coupling waveguide is located at the side of the first coupling waveguide, and there is a gap between the first coupling waveguide and the second coupling waveguide; one end of the first coupling waveguide is connected to the other end of the connecting section, the width of one end of the first coupling waveguide is greater than the width of the other end of the first coupling waveguide; the width of one end of the second coupling waveguide is greater than the width of the other end of the second coupling waveguide;

[0013] A beam splitting section includes a third waveguide and a fourth waveguide, one end of the third waveguide is connected to the other end of the first coupling waveguide, one end of the fourth waveguide is connected to the other end of the second coupling waveguide, and there is a gap between the third waveguide and the fourth waveguide.

[0014] In a second aspect, the polarization rotation beam splitter provided by the present disclosure comprises:

[0015] A mode conversion section includes a first waveguide and a second waveguide, the second waveguide is arranged above the first waveguide, and the bottom of the second waveguide is connected to the top of the first waveguide, the thickness of the second waveguide is greater than the thickness of the first waveguide; the width of one end of the second waveguide is greater than the width of the other end of the second waveguide, the width of one end of the second waveguide is greater than the width of one end of the first waveguide, and the width of the other end of the first waveguide is greater than the width of the other end of the second waveguide;

[0016] A connecting section is connected to the other end of the first waveguide, and the width of one end of the connecting section is greater than the width of the other end of the connecting section.

[0017] A mode coupling section includes a first coupling waveguide and a second coupling waveguide, the second coupling waveguide is located at the side of the first coupling waveguide, and there is a gap between the first coupling waveguide and the second coupling waveguide; one end of the first coupling waveguide is connected to the other end of the connecting section, the width of one end of the first coupling waveguide is greater than the width of the other end of the first coupling waveguide; the width of one end of the second coupling waveguide is greater than the width of the other end of the second coupling waveguide; one end of the second coupling waveguide is provided with a curved waveguide, the curved waveguide is located at one side of the connecting section, one end of the curved waveguide extends away from the connecting section, and the other end of the curved waveguide is connected to one end of the second coupling waveguide;

[0018] A beam splitting section includes a third waveguide and a fourth waveguide, one end of the third waveguide is connected to the other end of the first coupling waveguide, one end of the fourth waveguide is connected to the other end of the second coupling waveguide, and there is a gap between the third waveguide and the fourth waveguide.

[0019] In a third aspect, the optical chip provided by the present disclosure is provided, and a polarization rotation beam splitter is arranged at an entrance of the optical chip, the polarization rotation beam splitter is used for polarization multiplexing beam splitting, wherein the polarization rotation beam splitter is the polarization rotation beam splitter provided by the first aspect, or the polarization rotation beam splitter is the polarization rotation beam splitter provided by the second aspect.

[0020] In a fourth aspect, the optical chip provided by the present disclosure is provided, and a polarization rotation beam splitter is arranged at an exit of the optical chip, the polarization rotation beam splitter is reversely arranged at the exit, and the polarization rotation beam splitter is used for polarization multiplexing beam splitting, wherein the polarization rotation beam splitter is the polarization rotation beam splitter provided by the first aspect, or the polarization rotation beam splitter is the polarization rotation beam splitter provided by the second aspect.

[0021] In a fifth aspect, the optical module provided by the present disclosure is provided, and the optical module comprises a circuit board.

[0022] An optical chip is electrically connected to the circuit board, and the optical chip is the optical chip provided by the third aspect and / or the optical chip provided by the fourth aspect.

[0023] In the polarization rotation beam splitter, the optical chip and the optical module provided by the present disclosure, a polarization multiplexing beam comprising TM0 polarized light and TE0 polarized light is input to the polarization rotation beam splitter after being converted by the mode conversion part, the TM0 polarized light is converted into TE1 polarized light by mode hybridization in the mode conversion part, the TE1 polarized light is coupled and transmitted to the mode coupling part through the connecting part, the mode coupling part couples the TE1 polarized light to the second coupling waveguide and converts it into TE0 polarized light through the mode coupling effect, and finally outputs the TE0 polarized light through the fourth waveguide of the beam splitting part; the TE0 polarized light is transmitted to the third waveguide of the beam splitting part along the first coupling waveguide of the mode conversion part, the connecting part and the mode coupling part, and finally output through the third waveguide. Therefore, the polarization rotation beam splitter provided by the present disclosure can realize polarization multiplexing beam splitting, which is convenient for fiber multiplexing in the optical module, and further convenient for high-bandwidth requirements of the optical module. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the present disclosure, the drawings used in some embodiments of the present disclosure will be briefly introduced below. Obviously, the drawings in the following description are only some drawings of the embodiments of the present disclosure, and other drawings can also be obtained by those skilled in the art according to these drawings. In addition, the drawings in the following description can be regarded as schematic diagrams, and are not limited to the actual size, actual process, actual time sequence, etc. of the products, methods, signals, etc. involved in the embodiments of the present disclosure.

[0025] Figure 1 A local architecture diagram of an optical communication system is provided according to some embodiments of the present disclosure;

[0026] Figure 2 A partial structural diagram of a host computer according to some embodiments of the present disclosure;

[0027] Figure 3 A structural diagram of an optical module according to some embodiments of the present disclosure;

[0028] Figure 4 An exploded view of an optical module according to some embodiments of the present disclosure;

[0029] Figure 5 An internal structural schematic diagram of an optical module according to some embodiments of the present disclosure;

[0030] Figure 6 A structural schematic diagram of an optical chip according to some embodiments of the present disclosure;

[0031] Figure 7 A structural schematic diagram of a polarization-rotating beam splitter according to some embodiments of the present disclosure; Figure 1

[0032] Figure 8 A sectional view in the direction of A-A; Figure 7

[0033] Figure 9 A partial enlarged view of a polarization-rotating beam splitter according to some embodiments of the present disclosure; Figure 1

[0034] Figure 10 A partial enlarged view of a polarization-rotating beam splitter according to some embodiments of the present disclosure; Figure 2

[0035] Figure 11 A partial enlarged view of a polarization-rotating beam splitter according to some embodiments of the present disclosure; Figure 3

[0036] Figure 12 A partial enlarged view of a polarization-rotating beam splitter according to some embodiments of the present disclosure; Figure 4

[0037] Figure 13 A structural schematic diagram of a polarization-rotating beam splitter according to some embodiments of the present disclosure; Figure 2

[0038] Figure 14 A sectional view in the direction of B-B; Figure 9

[0039] Figure 15 A sectional view in the direction of C-C; Figure 9

[0040] ​​​​​​​​​Figure 16 A structural diagram of a mode conversion unit according to some embodiments of the present disclosure;

[0041] Figure 17 A structural diagram of a mode conversion unit according to some embodiments of the present disclosure; Figure 10 A sectional view in the direction of D-D;

[0042] Figure 18 A structural diagram of a mode conversion unit according to some embodiments of the present disclosure; Figure 10 A sectional view in the direction of E-E;

[0043] Figure 19 A structural diagram of a mode conversion unit according to some embodiments of the present disclosure; Figure 11 A sectional view in the direction of F-F;

[0044] Figure 20 A partial enlarged view of a polarization rotation beam splitter according to some embodiments of the present disclosure;

[0045] Figure 21 A structural diagram of another mode coupling unit according to some embodiments of the present disclosure;

[0046] Figure 22 A structural diagram of another mode coupling unit according to some embodiments of the present disclosure;

[0047] Figure 23 A structural diagram of another mode coupling unit according to some embodiments of the present disclosure; Figure 12 A sectional view in the direction of G-G. DETAILED DESCRIPTION

[0048] Some embodiments of the present disclosure will be described in detail below with reference to the drawings. However, the described embodiments are only some embodiments of the present disclosure, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided by the present disclosure are within the scope of protection of the present disclosure.

[0049] Unless otherwise required by the context, throughout the specification and claims, the term "comprising" is to be interpreted as open, inclusive, meaning "including, but not limited to"; the terms "first", "second" are not to be interpreted as indicating or implying relative importance or indicating the upper limit of the number; the term "multiple" means two or more; the term "connected" should be interpreted broadly, for example, "connected" can be fixedly connected, or detachably connected, or integrated, can be directly connected, or indirectly connected through an intermediate medium; the use of the terms "adapted for" or "configured for" means open and inclusive language, which does not exclude devices adapted for or configured to perform additional tasks or steps; the terms "parallel", "perpendicular", "same", "consistent", "flush" and the like are not limited to absolute mathematical theoretical relationships, but also include acceptable error ranges generated in practice, and also include differences based on the same design concept but due to manufacturing reasons.

[0050] In optical communication technology, in order to establish information transmission between information processing devices, information needs to be loaded onto light, and the transmission of information is achieved by the propagation of light. Here, the light loaded with information is an optical signal. The optical signal can reduce the loss of optical power when transmitted in the information transmission device, so as to achieve high-speed, long-distance and low-cost information transmission. The signal that can be recognized and processed by the information processing device is an electrical signal. The information processing device usually includes an optical network unit (ONU), a gateway, a router, a switch, a mobile phone, a computer, a server, a tablet computer, a television, etc., and the information transmission device usually includes an optical fiber and a third coupling waveguide, etc.

[0051] The optical module can realize the mutual conversion between the optical signal and the electrical signal between the information processing device and the information transmission device. For example, at least one of the optical signal input end or the optical signal output end of the optical module is connected with an optical fiber, and at least one of the electrical signal input end or the electrical signal output end of the optical module is connected with an optical network unit; a first optical signal from the optical fiber is transmitted to the optical module, the optical module converts the first optical signal into a first electrical signal, and transmits the first electrical signal to the optical network unit; a second electrical signal from the optical network unit is transmitted to the optical module, the optical module converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber. Since multiple information processing devices can transmit information through electrical signals, at least one of the multiple information processing devices needs to be directly connected with the optical module, without the need for all the information processing devices to be directly connected with the optical module. Here, the information processing device directly connected with the optical module is referred to as the host computer of the optical module. In addition, the optical signal input end or the optical signal output end of the optical module can be referred to as an optical port, and the electrical signal input end or the electrical signal output end of the optical module can be referred to as an electrical port.

[0052] Figure 1 A partial structure diagram of an optical communication system according to some embodiments of the present disclosure is provided. As shown in FIG. 1, the optical communication system mainly includes a remote information processing device 1000, a local information processing device 2000, a host computer 100, an optical module 200, an optical fiber 101 and a network cable 103. Figure 1

[0053] ​One end of the optical fiber 101 extends towards the direction of the remote information processing device 1000, and the other end of the optical fiber 101 is connected to the optical module 200 through the optical port of the optical module 200. The optical signal can be totally reflected in the optical fiber 101, and the propagation of the optical signal in the total reflection direction can maintain the original optical power. The optical signal is totally reflected in the optical fiber 101 multiple times to transmit the optical signal from the remote information processing device 1000 to the optical module 200, or to transmit the optical signal from the optical module 200 to the remote information processing device 1000, thereby realizing long-distance and low-power-loss information transmission.

[0054] The optical communication system can include one or more optical fibers 101, and the optical fiber 101 is detachably connected or fixedly connected to the optical module 200. The host computer 100 is configured to provide a data signal to the optical module 200, or receive a data signal from the optical module 200, or monitor or control the working state of the optical module 200.

[0055] The host computer 100 includes a housing substantially in the shape of a rectangular cuboid, and an optical module interface 102 disposed on the housing. The optical module interface 102 is configured to access the optical module 200 to establish a one-way or two-way electrical signal connection between the host computer 100 and the optical module 200.

[0056] The host computer 100 further comprises an external electrical interface configured to access an electrical signal network. For example, the external electrical interface comprises a Universal Serial Bus (USB) interface or a network cable interface 104 configured to access a network cable 103 to establish a unidirectional or bidirectional electrical signal connection between the host computer 100 and the network cable 103. One end of the network cable 103 is connected to the local information processing device 2000, and the other end of the network cable 103 is connected to the host computer 100 to establish an electrical signal connection between the local information processing device 2000 and the host computer 100 through the network cable 103. For example, a third electrical signal emitted by the local information processing device 2000 is transmitted to the host computer 100 through the network cable 103, and the host computer 100 generates a second electrical signal according to the third electrical signal. The second electrical signal from the host computer 100 is transmitted to the optical module 200, and the optical module 200 converts the second electrical signal into a second optical signal and transmits the second optical signal to the optical fiber 101. The second optical signal is transmitted in the optical fiber 101 to the remote information processing device 1000. For example, the first optical signal from the remote information processing device 1000 is transmitted through the optical fiber 101, the first optical signal from the optical fiber 101 is transmitted to the optical module 200, the optical module 200 converts the first optical signal into a first electrical signal, the optical module 200 transmits the first electrical signal to the host computer 100, the host computer 100 generates a fourth electrical signal according to the first electrical signal, and the fourth electrical signal is transmitted to the local information processing device 2000. It should be noted that the optical module is a tool for converting optical signals and electrical signals, and the information does not change in the conversion process of the optical signals and the electrical signals, and the encoding and decoding mode of the information can change.

[0057] The host computer 100 comprises an optical line terminal (OLT), an optical network terminal (ONT), or a data center server in addition to the optical network terminal.

[0058] Figure 2 A partial structural diagram of a host computer according to some embodiments of the present disclosure is provided. In order to clearly show the connection relationship between the optical module 200 and the host computer 100, Figure 2 Only the structure of the host computer 100 related to the optical module 200 is shown. As Figure 2 shown, the host computer 100 further comprises a PCB circuit board 105 arranged in the housing, a cage 106 arranged on the surface of the PCB circuit board 105, a heat sink 107 arranged on the cage 106, and an electrical connector arranged inside the cage 106. The electrical connector is configured to access the electrical port of the optical module 200; the heat sink 107 has a protruding structure such as fins to increase the heat dissipation area.

[0059] The light module 200 is inserted into the cage 106 of the host computer 100, and the light module 200 is fixed by the cage 106. The heat generated by the light module 200 is conducted to the cage 106, and then diffused through the heat sink 107. After the light module 200 is inserted into the cage 106, the electrical port of the light module 200 is connected to the electrical connector inside the cage 106, so that the light module 200 and the host computer 100 establish a bidirectional electrical signal connection. In addition, the optical port of the light module 200 is connected to the optical fiber 101, so that the light module 200 and the optical fiber 101 establish a bidirectional optical signal connection.

[0060] Figure 3 FIG. 1 is a structural diagram of a light module according to some embodiments of the present disclosure, Figure 4 FIG. 2 is an exploded view of the light module according to some embodiments of the present disclosure. As shown in Figure 3 and Figure 4 The light module 200 includes a shell, a circuit board 300 arranged in the shell, a light chip 400, and a light source 500. The light chip 400 and the light source 500 are electrically connected to the circuit board 300, respectively. The light emitting end of the light source 500 is optically coupled to the light chip 400. In some embodiments, the light emitting end of the light source 500 is coupled to the light chip 400 through an optical fiber.

[0061] The shell includes an upper shell 201 and a lower shell 202. The upper shell 201 covers the lower shell 202 to form the shell having two openings 204 and 205. The outer contour of the shell generally presents a square body.

[0062] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 arranged perpendicularly to the bottom plate 2021 on both sides of the bottom plate 2021. The upper shell 201 includes a cover plate 2011, which covers the two lower side plates 2022 of the lower shell 202 to form the shell.

[0063] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 arranged perpendicularly to the bottom plate 2021 on both sides of the bottom plate 2021. The upper shell 201 includes a cover plate 2011 and two upper side plates arranged perpendicularly to the cover plate 2011 on both sides of the cover plate 2011. The two upper side plates and the two lower side plates 2022 are combined to cover the lower shell 202 by the upper shell 201.

[0064] The direction of the line connecting the two openings 204 and 205 can be consistent with the length direction of the light module 200, or can be inconsistent with the length direction of the light module 200. For example, the opening 204 is located at the end (left end) of the light module 200, and the opening 205 is also located at the end of the light module 200. Figure 3 ​Figure 3 The opening 204 is an electrical port, and the gold finger 301 of the circuit board 300 extends from the opening 204 and is inserted into the electrical connector of the host computer 100. The opening 205 is an optical port and is configured to access the external optical fiber 101 so that the optical fiber 101 is connected to the optical chip 400 in the optical module 200.

[0065] The upper shell 201 and the lower shell 202 are combined to facilitate the installation of the circuit board 300, the optical chip 400, and the light source 500 into the shells. The upper shell 201 and the lower shell 202 can encapsulate and protect the above-mentioned devices. In addition, when the circuit board 300, the optical chip 400, and the light source 500 are assembled, the positioning components, the heat dissipation components, and the electromagnetic shielding components of these devices can be arranged, which facilitates the automatic production.

[0066] In some embodiments, the upper shell 201 and the lower shell 202 are made of metal materials, which facilitates electromagnetic shielding and heat dissipation.

[0067] In some embodiments, the optical module 200 further includes an unlocking component 600 outside the shell. The unlocking component 600 is configured to achieve the fixed connection between the optical module 200 and the host computer or to release the fixed connection between the optical module 200 and the host computer.

[0068] For example, the unlocking component 600 is located outside the two lower side plates 2022 of the lower shell 202 and includes a clamping component that matches the cage 106 of the host computer 100. When the optical module 200 is inserted into the cage 106, the clamping component of the unlocking component 600 fixes the optical module 200 in the cage 106. When the unlocking component 600 is pulled, the clamping component of the unlocking component 600 moves, thereby changing the connection relationship between the clamping component and the host computer, releasing the fixed connection between the optical module 200 and the host computer, and allowing the optical module 200 to be pulled out of the cage 106.

[0069] Circuit board 300 includes circuit traces, electronic components, and chips. The circuit traces connect the electronic components and chips according to the circuit design to achieve functions such as power supply, electrical signal transmission, and grounding. Electronic components may include, for example, capacitors, resistors, transistors, and metal-oxide-semiconductor field-effect transistors (MOSFETs). Chips may include, for example, microcontroller units (MCUs), laser driver chips, transimpedance amplifiers (TIAs), limiting amplifiers (LAs), clock and data recovery chips (CDRs), power management chips, and digital signal processing (DSP) chips.

[0070] Circuit board 300 is generally a rigid circuit board. Due to its relatively hard material, the rigid circuit board can also perform a load-bearing function. For example, the rigid circuit board can stably support the aforementioned electronic components and chips. The rigid circuit board can also be inserted into the electrical connector in the cage 106 of the host computer 100.

[0071] The circuit board 300 also includes gold fingers 301 formed on its end surface, the gold fingers 301 consisting of a plurality of independent pins. The circuit board 300 is inserted into the cage 106 and is connected to an electrical connector within the cage 106 by the gold fingers 301. The gold fingers 301 may be provided only on one side of the surface of the circuit board 300 (e.g., Figure 4 The upper surface shown can also be positioned on the upper and lower surfaces of the circuit board 300 to provide a greater number of pins, thus adapting to applications with high pin count requirements. The gold fingers 301 are configured to establish an electrical connection with the host computer to achieve power supply, grounding, two-wire synchronous serial (Inter-Integrated Circuit, I2C) signal transmission, and data signal transmission. Of course, flexible circuit boards are also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards as a supplement to rigid circuit boards.

[0072] Figure 5 This is a schematic diagram of the internal structure of an optical module according to some embodiments of the present disclosure. Figure 5As shown, in some embodiments, the light source 500 is arranged at the side of the optical chip 400, and the light source 500 emits light sideways and is coupled into the optical chip 400. The light source 500 serves as an external light source of the optical chip 400, and the light emitted by the light source 500 enters the optical chip 400. The light source 500 can be a laser box, which encapsulates a laser inside. The laser emits a laser beam, and the light source 500 is used to provide a laser emission to the optical chip 400. The laser has better single-wavelength characteristics and better wavelength tuning characteristics, and thus becomes the preferred light source for optical modules and even optical fiber 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, the characteristics and chip components of the light sources are quite different from those of lasers, so that there is a large technical difference between optical modules using lasers and optical modules using other light sources. Generally, those skilled in the art will not consider that the two types of optical modules can give technical inspiration to each other.

[0073] The light emitted by the light source 500 is light without carrying data, which enters the optical chip 400. The optical chip 400 performs phase modulation on the light to load electrical signals into the light, so as to obtain light carrying data, i.e., to generate an optical emission signal, thereby realizing emission of the optical signal.

[0074] In some embodiments, the optical chip 400 can be a silicon optical chip, i.e., the optical chip 400 is encapsulated by using silicon material. The silicon optical chip includes a Mach-Zehnder modulator (MZM), and a silicon optical phase modulator is integrated inside the MZM. The silicon optical phase modulator is used to realize modulation and demodulation of the optical signal.

[0075] In some embodiments, the optical chip 400 can be a thin-film lithium niobate chip, i.e., the optical chip 400 is encapsulated by using thin-film lithium niobate material. The thin-film lithium niobate has the characteristics of linear electro-optic effect, and an external electric field can cause linear changes in the refractive index in the corresponding direction, so that the light wave transmitted in the medium has controllable intensity, phase, and other information. Therefore, the thin-film lithium niobate is selected as the material of the optical modulator, so as to realize higher modulation efficiency and the like.

[0076] In some embodiments, the optical chip 400 can be a hybrid InP / Si optical chip, i.e., the hybrid InP / Si optical chip is encapsulated by mixing InP material and silicon material. The hybrid InP / Si optical chip can combine the performance of the InP material and the performance of the silicon material, so that the optical chip 400 has good performance and is convenient for improving the bandwidth of the optical chip 400.

[0077] Figure 6 FIG. 1 shows a structural schematic diagram of an optical chip according to some embodiments of the present disclosure. As shown in FIG. 1, the optical chip 400 includes a light source 500 and a modulator 600. Figure 6As shown, one side of the optical chip 400 is provided with an entrance port 410, and a polarization rotation beam splitter 700 is arranged in the entrance port 410. The polarization multiplexed light beam is coupled to the polarization rotation beam splitter 700 through the entrance port 410, and the polarization rotation beam splitter 700 transmits the polarization multiplexed light beam after beam splitting. For example, the polarization multiplexed light beam includes TM0 polarized light and TE0 polarized light, and the polarization rotation beam splitter 700 splits the polarization multiplexed light beam into two TE0 polarized light beams.

[0078] In some embodiments, the entrance port 410 of the optical chip 400 can be provided with one or more, such as two, three, four, etc.

[0079] In some embodiments, the other side of the optical chip 400 is provided with an exit port 420, and a polarization rotation beam splitter 700 can be arranged in the exit port 420. For example, the polarization rotation beam splitter 700 arranged in the exit port 420 is arranged in the opposite direction to the polarization rotation beam splitter 700 arranged in the entrance port 410, so that the polarization rotation beam splitter 700 in the exit port 420 is used for polarization multiplexing the polarization multiplexed light beam to polarize two polarized light beams into one polarized light beam. For example, two TE0 polarized light beams are polarization multiplexed into a light beam including TM0 polarized light and TE0 polarized light.

[0080] In some embodiments, the exit port 420 of the optical chip 400 can be provided with one or more, such as two, three, four, etc.

[0081] In some embodiments, the entrance port 410 and the exit port 420 can be arranged on the same side or adjacent sides of the optical chip 400.

[0082] In some embodiments, the entrance port 410 is coupled to a light source 500 or a fiber outside the optical module. When the entrance port 410 is coupled to the light source 500, the polarization rotation beam splitter 700 in the entrance port 410 splits the light beam without carrying signals; when the entrance port 410 is coupled to the fiber outside the optical module, the polarization rotation beam splitter 700 in the entrance port 410 splits the light beam carrying signals.

[0083] In some embodiments, the exit port 420 is used to output the modulated light signal of the optical chip 400, and the polarization rotation beam splitter 700 of the exit port 420 is used to output the light beam carrying signals.

[0084] Figure 7 A structure diagram of a polarization rotation beam splitter according to some embodiments of the present disclosure Figure 1 , Figure 8 A structure diagram of a polarization rotation beam splitter according to some embodiments of the present disclosure Figure 7 A sectional view in the A-A direction Figure 7 and Figure 8 A structure diagram of a polarization rotation beam splitter according to some embodiments of the present disclosureFigure 7 and Figure 8 The structure is shown below. The polarization-rotating beam splitter 700 provided by the embodiments of the present disclosure is described in detail below in combination with Figure 7 , Figure 8 and other drawings.

[0085] In some embodiments, the polarization-rotating beam splitter 700 includes a mode conversion part 710, which is formed with a tapered waveguide structure, and is used to convert a TM0 polarized light mode into a TE1 polarized light.

[0086] In some embodiments, the mode conversion part 710 includes a first waveguide 711 and a second waveguide 712, the first waveguide 711 is arranged below the second waveguide 712, and the bottom of the second waveguide 712 is connected to the first waveguide 711. The thickness of the second waveguide 712 is greater than the thickness of the first waveguide 711. For example, the first waveguide 711 and the second waveguide 712 form an irregular ridge waveguide structure.

[0087] A polarization multiplexed light beam including TM0 polarized light and TE0 polarized light is coupled into the mode conversion part 710 from one end of the mode conversion part 710. For example, one end of the second waveguide 712 is the coupling end of the polarization multiplexed light beam, that is, the polarization multiplexed light beam is input from one end of the second waveguide 712. During transmission, the polarization multiplexed light beam is gradually coupled from the second waveguide 712 into the first waveguide 711, and the TM0 polarized light is converted into TE1 polarized light during propagation by mode hybridization.

[0088] Figure 9 A partial enlargement of a polarization-rotating beam splitter according to some embodiments of the present disclosure Figure 1 In some embodiments, the second waveguide 712 is located at the center of the top of the first waveguide 711, and of course the embodiments of the present disclosure are not limited to arranging the second waveguide 712 at the center of the top of the first waveguide 711. Of course, the embodiments of the present disclosure are not limited to arranging the second waveguide 712 above the first waveguide 711, but can also be arranged below the first waveguide 711.

[0089] In some embodiments, the width of one end of the first waveguide 711 is smaller than the width of the other end of the first waveguide 711. For example, the first waveguide 711 is a tapered waveguide.

[0090] In some embodiments, the width of one end of the second waveguide 712 is greater than the width of the other end of the second waveguide 712. For example, the second waveguide 712 is a tapered waveguide.

[0091] In some embodiments, the width of one end of the second waveguide 712 is greater than or equal to the width of one end of the first waveguide 711, and the width of the second waveguide 712 is smaller than the width of the other end of the first waveguide 711.

[0092] In some embodiments, the width of one end of the first waveguide 711 is greater than or equal to 0.7 μm, and the width of the other end of the first waveguide 711 is less than or equal to 2 μm. For example, the width of the first waveguide 711 is 0.8 μm, and the width of the other end of the first waveguide 711 is 2 μm.

[0093] In some embodiments, the width of one end of the second waveguide 712 is less than or equal to 0.7 μm, and the width of the other end of the second waveguide 712 is less than or equal to 0.1 μm. For example, the width of one end of the second waveguide 712 is 0.7 μm, and the width of the other end of the second waveguide 712 is 0.05 μm.

[0094] In some embodiments, the polarization-rotating beam splitter 700 comprises a connecting portion 720. One end of the connecting portion 720 is connected to the other end of the mode conversion portion 710, and the connecting portion 720 is used to adapt the other end of the mode conversion portion 710. For example, one end of the connecting portion 720 is connected to the other end of the first waveguide 711.

[0095] In some embodiments, the width of one end of the connecting portion 720 is greater than the width of the other end of the connecting portion 720. For example, the connecting portion 720 is a tapered waveguide.

[0096] Figure 10 A partial enlargement of a polarization-rotating beam splitter according to some embodiments of the present disclosure Figure 2 In some embodiments, the connecting portion 720 comprises a tapered waveguide 721 and a straight waveguide 722. One end of the tapered waveguide 721 is connected to the other end of the first waveguide 711, and the other end of the tapered waveguide 721 is connected to one end of the straight waveguide 722. The width of one end of the tapered waveguide 721 is greater than the width of the other end of the tapered waveguide 721. The tapered waveguide 721 is used to adapt the width of the connecting portion. The straight waveguide 722 is arranged in the connecting portion 720 to reduce the back-coupling of the light beam at the other end of the tapered waveguide 721 into the tapered waveguide 721.

[0097] In some embodiments, the polarization-rotating beam splitter 700 comprises a mode coupling portion 730. The mode coupling portion 730 uses the mode coupling effect to split the TE1 polarized light and the TE0 polarized light and to convert the TE1 polarized light into the TE0 polarized light.

[0098] Figure 11 A partial enlargement of a polarization-rotating beam splitter according to some embodiments of the present disclosure Figure 3In some embodiments, the mode coupling section 730 includes a first coupling waveguide 731 and a second coupling waveguide 732. One end of the first coupling waveguide 731 is connected to the other end of the connecting section 720, and the second coupling waveguide 732 is located on the side of the first coupling waveguide 731. A gap exists between the first coupling waveguide 731 and the second coupling waveguide 732. For example, as... Figure 11 As shown, the second coupling waveguide 732 is located above the first coupling waveguide 731, and there is a gap between the upper side of the first coupling waveguide 731 and the upper side of the second coupling waveguide 732. Alternatively, in this embodiment, the second coupling waveguide 732 may also be located below the first coupling waveguide 731. In this embodiment, the first coupling waveguide 731 and the second coupling waveguide 732 generate a mode coupling effect, causing the TE1 polarized light output from the connecting portion 720 to be coupled into the second coupling waveguide 732 and converted into TE0 polarized light. The TE0 polarized light output from the connecting portion 720 continues to propagate along the first coupling waveguide 731, thereby achieving beam splitting of the TE1 and TE0 polarized light.

[0099] In some embodiments, the width of one end of the first coupling waveguide 731 is greater than the width of the other end of the first coupling waveguide 731. For example, the first coupling waveguide 731 is a tapered waveguide, such as a symmetrical tapered waveguide or an asymmetrical tapered waveguide.

[0100] In some embodiments, the width of one end of the second coupling waveguide 732 is smaller than the width of the other end of the second coupling waveguide 732. For example, the second coupling waveguide 732 is a tapered waveguide, such as a symmetrical tapered waveguide or an asymmetrical tapered waveguide.

[0101] In some embodiments, the width of one end of the first coupling waveguide 731 is greater than the width of the other end of the second coupling waveguide 732, and the width of the other end of the first coupling waveguide 731 is greater than the width of one end of the second coupling waveguide 732.

[0102] In some embodiments, the polarization rotating beam splitter 700 includes a beam splitting section 740, one end of which is connected to a mode coupling section 730. The beam splitting section 740 is used to split and transmit two TEO polarized beams output by the mode coupling section 730. The beam splitting section 740 facilitates the polarization rotating beam splitter 700 to output two TEO polarized beams.

[0103] Figure 12 This is a partial magnification of a polarization rotating beam splitter provided according to some embodiments of the present disclosure. Figure 4In some embodiments, the beam splitting part 740 includes a third waveguide 741 and a fourth waveguide 742, one end of the third waveguide 741 is connected to the other end of the first coupling waveguide 731, and one end of the fourth waveguide 742 is connected to the other end of the second coupling waveguide 732. The third waveguide 741 serves as one output end of the polarization rotation beam splitter 700 for outputting one beam of TE0 polarized light, and the fourth waveguide 742 serves as the other output end of the polarization rotation beam splitter 700 for outputting another beam of TE0 polarized light. There is a gap between the third waveguide 741 and the fourth waveguide 742, and the width of the other end of the gap is greater than the width of one end of the gap, which helps to effectively reduce the coupling between the two beams of TE0 polarized light when the other end of the third waveguide 741 and the other end of the fourth waveguide 742 are close to each other, thereby facilitating the reduction of crosstalk between the two beams of TE0 polarized light at the output end of the polarization rotation beam splitter 700.

[0104] In some embodiments, the third waveguide 741 includes an epitaxial waveguide 7411, one end of the epitaxial waveguide 7411 is connected to the other end of the first coupling waveguide 731, and the epitaxial waveguide 7411 extends away from the center line of the other end of the first coupling waveguide 731. For example, the epitaxial waveguide 7411 extends away from the second coupling waveguide 732, so as to adjust the gap between the third waveguide 741 and the fourth waveguide 742.

[0105] In some embodiments, the third waveguide 741 includes a first straight waveguide 7412 located at the end of the third waveguide 741, facilitating the coupling connection of the third waveguide 741 with other structures. For example, one end of the first straight waveguide 7412 is connected to the other end of the epitaxial waveguide 7411, and the smooth transition from the other end of the first coupling waveguide 731 to the one end of the first straight waveguide 7412 is realized through the epitaxial waveguide 7411, so that the gap between the third waveguide 741 and the fourth waveguide 742 gradually expands.

[0106] In some embodiments, the epitaxial waveguide 7411 adopts a Bessel curved waveguide, an Euler curved waveguide, a circular arc waveguide, etc., so that the epitaxial waveguide 7411 extends smoothly, effectively reducing the occurrence of sharp places on the epitaxial waveguide 7411 and causing damage to the light beam reflection.

[0107] In some embodiments, the fourth waveguide 742 includes a second straight waveguide 7421, one end of the second straight waveguide 7421 is connected to the other end of the second coupling waveguide 732. The second straight waveguide 7421 is located at the end of the fourth waveguide 742, facilitating the coupling connection of the fourth waveguide 742 with other structures.

[0108] In some embodiments, one end of the epitaxial waveguide 7411 is close to the second straight waveguide 7421, and the other end of the epitaxial waveguide 7411 is away from the second straight waveguide 7421.

[0109] In some embodiments, the fourth waveguide 742 may include an epitaxial waveguide, one end of which is connected to the other end of the second coupling waveguide 732, and the epitaxial waveguide extends in a direction away from the centerline of the other end of the second coupling waveguide 732. For example, the epitaxial waveguide extends in a direction away from the first coupling waveguide 732 to facilitate adjustment of the spacing between the third waveguide 741 and the fourth waveguide 742.

[0110] In some embodiments, the mode conversion section 710, the connection section 720, the mode coupling section 730, and the beam splitter section 740 form a beam splitter waveguide layer 700a.

[0111] Figure 13 This is a schematic diagram of the structure of a polarization rotating beam splitter according to some embodiments of the present disclosure. Figure 2 .like Figure 13 As shown, the polarization rotating beam splitter 700 includes a substrate 750, and a beam splitting waveguide layer 700a is disposed on the substrate 750.

[0112] In some embodiments, the substrate 750 includes a first substrate layer 751 and a second substrate layer 752, the second substrate layer 752 being disposed on the first substrate layer 751, and the beam splitter waveguide layer 700a being disposed on the second substrate layer 752.

[0113] In some embodiments, the polarization rotating beam splitter 700 includes a cladding 760 that wraps around the side of the beam splitting waveguide layer 700a.

[0114] In some embodiments, the structure of the beam splitter waveguide layer 700a can be made of materials such as Si, SiN, InP, lithium niobate (LiNbO3), the first substrate layer 751 is made of materials such as Si, the second substrate layer 752 is made of materials such as SiO2, and the cladding layer 760 is made of materials such as SiO2.

[0115] Figure 14 for Figure 9 Cross-sectional view along the BB direction. Figure 15 for Figure 9 Cross-sectional view along the CC direction. Figure 14 and Figure 15 A cross-sectional view of a mode conversion section is shown. For example... Figure 14 and Figure 15 As shown, the first waveguide 711 is a continuous symmetrical tapered waveguide, and the second waveguide 712 is a continuous symmetrical tapered waveguide, meaning that the first waveguide 711 and the second waveguide 712 change uniformly. However, this is not the only embodiment disclosed in this invention. In some embodiments, the mode conversion unit 710 has an axisymmetric structure.

[0116] Figure 16 This is a schematic diagram of the structure of a mode switching unit provided according to some embodiments of the present disclosure. Figure 16As shown, the first waveguide 711 includes a plurality of first tapered waveguides 7111 connected in sequence, and the width of one end of the first tapered waveguide 7111 is smaller than the width of the other end of the first tapered waveguide 7111. For example, the first waveguide 711 includes a first tapered waveguide 7111a, a first tapered waveguide 7111b, and a first tapered waveguide 7111n, etc. The first tapered waveguide 7111a, the first tapered waveguide 7111b, and the first tapered waveguide 7111n, etc. can have different lengths, and the side slopes of the first tapered waveguide 7111a, the first tapered waveguide 7111b, and the first tapered waveguide 7111n, etc. can be different, so that the first waveguide 711 is a discontinuous tapered waveguide structure.

[0117] In some embodiments, the plurality of first tapered waveguides 7111 in the first waveguide 711 can be symmetric tapered waveguides, but are not limited to symmetric tapered waveguides.

[0118] As shown, the second waveguide 712 includes a plurality of second tapered waveguides 7121 connected in sequence, and the width of one end of the second tapered waveguide 7121 is greater than the width of the other end of the second tapered waveguide 7121. For example, the second waveguide 712 includes a second tapered waveguide 7121a, a second tapered waveguide 7121b, and a second tapered waveguide 7121n, etc. The second tapered waveguide 7121a, the second tapered waveguide 7121b, and the second tapered waveguide 7121n, etc. can have different lengths, and the side slopes of the second tapered waveguide 7121a, the second tapered waveguide 7121b, and the second tapered waveguide 7121n, etc. can be different, so that the second waveguide 712 is a discontinuous tapered waveguide structure.

[0119] In some embodiments, the plurality of second tapered waveguides 7121 in the second waveguide 712 can be symmetric tapered waveguides, but are not limited to symmetric tapered waveguides.

[0120] Figure 17 For Figure 10 a cross-sectional view in the direction of D-D, Figure 17 a cross-sectional view in the direction of D-D, Figure 17 As shown, the width of the connection part 720 at D-D is smaller than the width of the first waveguide 711 at C-C.

[0121] Figure 18 For Figure 10 a cross-sectional view in the direction of E-E, Figure 19 a cross-sectional view in the direction of E-E, Figure 11 a cross-sectional view in the direction of F-F, Figure 20 a cross-sectional view in the direction of F-F, Figures 18-20 a cross-sectional view in the direction of F-F, Figures 18-20As shown, the first coupling waveguide 731 includes a first side surface 7311 located at a side of the first coupling waveguide 731 facing the second coupling waveguide 732; the second coupling waveguide 732 includes a second side surface 7321 located at a side of the second coupling waveguide 732 facing the first coupling waveguide 731. A spacing between the first side surface 7311 and the second side surface 7321 is a first preset value, which is about 0.3 μm. For example, the first preset value is greater than 0 μm and less than 0.3 μm, such as 0.1 μm, 0.15 μm, 0.2 μm, etc.

[0122] In some embodiments, the mode coupling part 730 further includes a curved waveguide 733 disposed at one end of the second coupling waveguide 732. For example, one end of the curved waveguide 733 is away from a side of the connecting part 720, and the other end of the curved waveguide 733 is connected to one end of the second coupling waveguide 732. The one end of the curved waveguide 733 extends away from the connecting part 720, and the curved waveguide 733 is used to reduce the coupling of the light beam from the second coupling waveguide 732 to the connecting part 720, so as to facilitate guaranteeing the performance of the polarization rotation beam splitter.

[0123] In some embodiments, the curved waveguide 733 can be a circular arc waveguide or a spiral waveguide, etc.

[0124] In some embodiments, the curved waveguide 733 is located at a side of the straight waveguide 722, so as to increase the distance between the curved waveguide 733 and the straight waveguide 722 and reduce the coupling of the light beam from the second coupling waveguide 732 to the straight waveguide 722.

[0125] In some embodiments, the first side surface 7311 is a continuous and flat side surface, and the second side surface 7321 is a continuous and flat side surface. For example, the first coupling waveguide 731 is a symmetric tapered waveguide, so as to form the continuous first side surface 7311 at a side of the first coupling waveguide 731; the second coupling waveguide 732 is a symmetric tapered waveguide, so as to form the continuous second side surface 7321 at a side of the second coupling waveguide 732. Of course, in the embodiments of the present disclosure, the first coupling waveguide 731 and the second coupling waveguide 732 are not limited to the symmetric tapered waveguide.

[0126] Figure 21 FIG. 6 is a structural diagram of another mode coupling part according to some embodiments of the present disclosure, Figure 21 FIGS. 6(a) and 6(b) respectively show a mode coupling part structure. As shown in FIG. 6(a), Figure 21 In the mode coupling part 730, the first coupling waveguide 731 and the second coupling waveguide 732 are both asymmetric tapered waveguides; or, the first coupling waveguide 731 is a symmetric tapered waveguide, and the second coupling waveguide 732 is an asymmetric tapered waveguide. Of course, in the embodiments of the present disclosure, the forms of the first coupling waveguide 731 and the second coupling waveguide 732 are not limited to this.

[0127] Figure 22 FIG. 6 shows a structure diagram of another mode coupling part according to some embodiments of the present disclosure, Figure 22 FIG. 6 shows a structure diagram of another mode coupling part according to some embodiments of the present disclosure, Figure 22 As shown in FIG. 6, in some embodiments, the first coupling waveguide 731 includes a multi-section waveguide connected in sequence, wherein the multi-section waveguide includes a plurality of tapered waveguides, straight waveguides, etc.

[0128] In some embodiments, in the first coupling waveguide 731, one side of the multi-section waveguide is respectively provided with a first sub-side surface 7311a, a first sub-side surface 7311b, a first sub-side surface 7311c, etc., and the first sub-side surface 7311a, the first sub-side surface 7311b, the first sub-side surface 7311c, etc. are connected in sequence to form the first side surface 7311.

[0129] In some embodiments, the second coupling waveguide 732 includes a multi-section waveguide connected in sequence, wherein the multi-section waveguide includes a plurality of tapered waveguides, straight waveguides, etc.

[0130] In some embodiments, in the second coupling waveguide 732, one side of the multi-section waveguide is respectively provided with a second sub-side surface 7321a, a second sub-side surface 7321b, a second sub-side surface 7321c, etc., and the second sub-side surface 7321a, the second sub-side surface 7321b, the second sub-side surface 7321c, etc. are connected in sequence to form the second side surface 7321.

[0131] In some embodiments, the interval between the first sub-side surface 7311a and the second sub-side surface 7321a is a first preset value, the interval between the first sub-side surface 7311b and the second sub-side surface 7321b is a first preset value, the interval between the first sub-side surface 7311c and the second sub-side surface 7321c is a first preset value, etc.

[0132] Figure 23 FIG. 7 shows a structure diagram of another mode coupling part according to some embodiments of the present disclosure, Figure 12 FIG. 7 shows a structure diagram of another mode coupling part according to some embodiments of the present disclosure, Figure 23 FIG. 7 shows a structure diagram of another mode coupling part according to some embodiments of the present disclosure, Figure 23 As shown in FIG. 7, the interval between the first straight waveguide 7412 and the second straight waveguide 7421 is greater than the width of the first straight waveguide 7412, and the interval between the first straight waveguide 7412 and the second straight waveguide 7421 is greater than the width of the second straight waveguide 7421.

[0133] Comparison Figure 23 and Figure 19As shown in the cross-sectional view, the interval between the first straight waveguide 7412 and the second straight waveguide 7421 is greater than the first preset value. For example, the interval between the first straight waveguide 7412 and the second straight waveguide 7421 is 10 times the first preset value, etc.

[0134] In some embodiments, according to the optical path reversibility principle, two beams of TE0 polarized light corresponding to the end input of the beam splitter 740 can be multiplexed into a beam of polarized light including TM0 polarized light and TE0 polarized light, that is, polarization rotation beam combining is realized by using the polarization rotation beam splitter 700. Specifically: one beam of TE0 polarized light is input from the end of the fourth waveguide 742, transmitted against the direction of the polarization rotation beam splitter 700, and mode hybridization occurs in the polarization rotation beam splitter 700, and finally TM0 polarized light is output at one end of the mode conversion part 710; one beam of TE0 polarized light is input from the end of the third waveguide 741, transmitted against the direction of the polarization rotation beam splitter 700, and output at one end of the mode conversion part 710; and TM0 polarized light and TE0 polarized light are synthesized into a beam at one end of the mode conversion part 710.

[0135] Based on the second waveguide 712, the polarization rotation beam splitter 700 provided by the embodiments of the present disclosure is convenient to apply to optical links with thick waveguide layers, such as heterogeneous integrated optoelectronic chips. The polarization rotation beam splitter 700 provided by the embodiments of the present disclosure has a structure that is easy to process, a small device size, a large manufacturing tolerance, and a good working bandwidth performance, and has low loss and good polarization extinction ratio.

[0136] The polarization rotation beam splitter 700 provided by the embodiments of the present disclosure is not limited to be used in the optical chip 400 provided by the above embodiments, but can also be used in other optical chips involving polarization multiplexed light beams.

[0137] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and any person skilled in the art can think of changes or replacements within the technical range disclosed by the present disclosure, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A polarization-rotating beamsplitter, characterized by, The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof.

2. The polarization-rotating beamsplitter of claim 1, wherein, The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof.

3. The polarization-rotating beamsplitter of claim 1, wherein, The application relates to a beam splitting waveguide layer and a preparation method thereof.

4. The polarization-rotating beamsplitter of claim 3, wherein, The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof.

5. The polarization-rotating beamsplitter of claim 1, wherein, The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof.

6. The polarization-rotating beamsplitter of claim 5, wherein, The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. The application relates to a beam splitting waveguide layer and a preparation method thereof. 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7. The polarization-rotating beamsplitter of claim 1, wherein, The third waveguide comprises an epitaxial waveguide and a first straight waveguide, and the fourth waveguide comprises a second straight waveguide. One end of the epitaxial waveguide is connected to the other end of the first coupling waveguide, and the other end of the epitaxial waveguide is connected to the first straight waveguide; one end of the second straight waveguide is connected to the second coupling waveguide; one end of the epitaxial waveguide is close to the second straight waveguide, and the other end of the epitaxial waveguide is away from the second straight waveguide.

8. A polarization-rotating beamsplitter, characterized by Comprise: A mode conversion part comprises a first waveguide and a second waveguide, the second waveguide is arranged above the first waveguide, and the bottom of the second waveguide is connected to the top of the first waveguide, the thickness of the second waveguide is greater than the thickness of the first waveguide; the width of one end of the second waveguide is greater than the width of the other end of the second waveguide, the width of one end of the second waveguide is greater than the width of one end of the first waveguide, and the width of the other end of the first waveguide is greater than the width of the other end of the second waveguide; A connecting part, one end of which is connected to the other end of the first waveguide, the width of one end of the connecting part is greater than the width of the other end of the connecting part; A mode coupling part comprises a first coupling waveguide and a second coupling waveguide, the second coupling waveguide is located on the side of the first coupling waveguide, and there is a gap between the first coupling waveguide and the second coupling waveguide; one end of the first coupling waveguide is connected to the other end of the connecting part, and the width of one end of the first coupling waveguide is greater than the width of the other end of the first coupling waveguide; the width of one end of the second coupling waveguide is greater than the width of the other end of the second coupling waveguide; one end of the second coupling waveguide is provided with a curved waveguide, the curved waveguide is located on one side of the connecting part, one end of the curved waveguide extends away from the connecting part, and the other end of the curved waveguide is connected to one end of the second coupling waveguide; A beam splitting part comprises a third waveguide and a fourth waveguide, one end of the third waveguide is connected to the other end of the first coupling waveguide, one end of the fourth waveguide is connected to the other end of the second coupling waveguide, and there is a gap between the third waveguide and the fourth waveguide.

9. An optical chip, characterized by The light inlet of the optical chip is provided with a polarization rotation beam splitter, and the polarization rotation beam splitter is used for beam splitting of a polarization multiplexed light beam; wherein the polarization rotation beam splitter is the polarization rotation beam splitter of any one of claims 1-7; or, the polarization rotation beam splitter is the polarization rotation beam splitter of claim 8.

10. An optical module characterized by comprising: Comprise: A circuit board; An optical chip electrically connected to the circuit board, the optical chip is the optical chip of claim 9.

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