Optical chip, optical chip manufacturing method, optical signal transmission method and optical module

Abstract

The invention provides an optical chip, an optical chip manufacturing method, an optical signal transmission method and an optical module.The optical chip comprises an optical port coupled with an optical fiber and used for receiving a first optical signal from the optical fiber, and the first optical signal comprises a component in a transverse magnetic (TM) mode; the PSR is used for performing first processing on the first optical signal to generate a second optical signal, the second optical signal is in a transverse electric TE mode, and the second optical signal is a single-channel multi-wavelength optical signal; the at least one wavelength demultiplexer DeMux is used for performing second processing on the second optical signal to generate a third optical signal, and the third optical signal is a multi-channel single-wavelength optical signal; the photoelectric detector array is used for converting the third optical signal into an electric signal; wherein the optical port, the PSR, and the at least one DeMux are made of silicon nitride SiN.

Description

Technical Field

[0001] The present application relates to the field of optoelectronic communications, and more specifically, to an optical chip, an optical chip manufacturing method, an optical signal transmission method, and an optical module. Background Art

[0002] With the dramatic increase in data traffic, higher demands are placed on high-speed, low-cost optical communications. In order to obtain higher transmission speeds, one is to increase the single-channel rate, the second is to increase the number of channels for data transmission, and the third is to use wavelength division multiplexing to multiplex multiple wavelengths into one optical fiber for transmission. The use of wavelength division multiplexing / demultiplexing functions can effectively reduce the number of optical fibers used, reduce the cost of the communication system, and increase the data transmission rate. The receiving optical chip is the core component of the optical signal-electrical signal conversion of the optical communication system, and is mainly composed of passive optical devices and photodetectors.

[0003] At present, wavelength demultiplexing receiving optical chips mainly adopt on-chip integrated chips made by packaging planar lightwave circuit (PLC) of arrayed waveguide grating (AWG) filter of silicon dioxide SiO2 material and photodetector (PD) patch, or integrated chips made by integrating germanium Ge PD and AWG filter of SiO2 material and Si passive devices on silicon-on-insulator (SOI) platform. However, the wavelength demultiplexer (DeMux) made of Si material has large insertion loss, high temperature drift coefficient, requires temperature cooling control, and is expensive. Summary of the invention

[0004] The present application provides an optical chip, which realizes on-chip integration of low-loss wavelength division multiplexing receiving optical chip by adopting silicon nitride SiN-SOI hybrid integration, passive devices such as DeMux made of SiN material, and active photodetectors with excellent performance made through an SOI platform compatible with complementary metal oxide semiconductor (CMOS).

[0005] In a first aspect, an optical chip is provided, comprising: an optical port coupled to an optical fiber, for receiving a first optical signal from the optical fiber, wherein the first optical signal comprises a component of a transverse magnetic TM mode; a polarization splitter rotator PSR, for performing a first processing on the first optical signal to generate a second optical signal, wherein the second optical signal is a transverse electric TE mode, and the second optical signal is a single-channel multi-wavelength optical signal; at least one wavelength demultiplexer DeMux, for performing a second processing on the second optical signal to generate a third optical signal, wherein the third optical signal is a multi-channel single-wavelength optical signal; and a photodetector array, for converting the third optical signal into an electrical signal; wherein the optical port, the PSR and at least one DeMux are made of silicon nitride SiN.

[0006] Among them, a single-channel multi-wavelength optical signal can be understood as an optical signal including multiple wavelengths of light transmitted through an optical path (such as an optical fiber, a waveguide, etc.), and correspondingly, a multi-channel single-wavelength optical signal can be understood as the existence of multiple optical paths, and a single-wavelength optical signal is transmitted through each channel. Similar expressions in this application can be understood in this way and will not be repeated in the following text.

[0007] According to the solution of the present application, passive devices such as DeMux are prepared by SiN material, so that the optical chip is insensitive to temperature, has low insertion loss, does not require refrigerator control, and has low cost.

[0008] It should be understood that the PSR is coupled to the optical port via a first waveguide, and at least one DeMux is coupled to the PSR via a second waveguide, and the first waveguide and the second waveguide are made of SiN.

[0009] In combination with the first aspect, in some implementations of the first aspect, the photodetector array is connected to at least one DeMux via a third waveguide, and the third waveguide is made of SiN.

[0010] In combination with the first aspect, in certain implementations of the first aspect, the optical chip also includes: a waveguide conversion structure, used to couple and transmit the third optical signal from the third waveguide to the fourth waveguide, including a first part and a second part, the first part is coupled to at least one DeMux through the third waveguide, the second part is coupled to the photodetector array through the fourth waveguide, and the first part and the fourth waveguide are made of SiN.

[0011] In combination with the first aspect, in some implementations of the first aspect, the second portion of the waveguide conversion structure and the second waveguide are made of silicon Si.

[0012] In combination with the first aspect, in some implementations of the first aspect, the DeMux includes M stages of cascaded filter units, and the i-th stage of cascaded filter units includes 2 i Directionally coupled Mach-Zehnder interferometer DCMZI or 2i A micro-ring assisted Mach-Zehnder interferometer RMZI is provided, wherein the DCMZI includes N repeated DCMZI filter structures, the DCMZI filter structure includes two waveguide arms, and the RMZI includes L repeated RMZI filter structures, the RMZI filter structure includes a micro-ring resonant cavity, M, N, L are positive integers, i∈[1,M].

[0013] It should be understood that at this time, the third optical signal includes 2 M single wavelength optical signals of different wavelengths.

[0014] In combination with the first aspect, in certain implementations of the first aspect, the DeMux is an arrayed waveguide grating AWG filter, the AWG filter includes an output port and an array waveguide, the third optical signal is output from the output port, and the third optical signal includes K single-wavelength optical signals of different wavelengths.

[0015] In combination with the first aspect, in some implementations of the first aspect, the DeMux further includes 2 M An arrayed waveguide grating AWG filter is connected to the M-th cascaded filter unit in the M-th cascaded filter unit. Each AWG filter includes an output port and an arrayed waveguide. The third optical signal is output from the output port. The third optical signal includes K·2 M single wavelength optical signals of different wavelengths.

[0016] In combination with the first aspect, in certain implementations of the first aspect, the photodetector array adopts at least one structure of a PN junction photodiode PNPD, a PIN photodiode PIN PD, an avalanche diode APD, a single photon avalanche diode SPAD, a Schottky barrier diode SBD and a silicon photomultiplier tube SiPM.

[0017] In combination with the first aspect, in some implementations of the first aspect, the photodetector array is a detector made of a semiconductor material epitaxially grown by silicon on insulator (SOI).

[0018] In combination with the first aspect, in certain implementations of the first aspect, the optical chip further includes at least one of a semiconductor optical amplifier SOA, a laser diode LD, a modulator, a heater heater, a variable optical attenuator VOA, and a multiplexer Mux.

[0019] According to the solution of the present application, SiN-SOI hybrid integration is adopted, passive devices such as DeMux are made of SiN materials, and active photodetectors with excellent performance are made through a CMOS-compatible SOI platform, so that the on-chip integrated wavelength division multiplexing receiving optical chip does not require cooling and has low loss.

[0020] In a second aspect, a method for transmitting an optical signal is provided, the method comprising: a first optical signal enters an optical chip from an optical fiber through an optical port coupled to the optical fiber, the first optical signal comprising a component of a transverse magnetic TM mode; the first optical signal is subjected to a first processing by a polarization beam splitter rotator PSR to generate a second optical signal, the second optical signal is a transverse electric TE mode, and the second optical signal is a single-channel multi-wavelength optical signal; the second optical signal is subjected to a second processing by at least one wavelength demultiplexer DeMux to generate a third optical signal, the third optical signal is a multi-channel single-wavelength optical signal; the third optical signal is converted into an electrical signal by a photodetector array; wherein the optical port, the PSR and at least one DeMux are made of silicon nitride SiN.

[0021] It should be understood that the PSR is coupled to the optical port via a first waveguide, and at least one DeMux is coupled to the PSR via a second waveguide, and the first waveguide and the second waveguide are made of SiN.

[0022] In combination with the second aspect, in some implementations of the second aspect, the photodetector array is connected to at least one DeMux via a third waveguide, and the third waveguide is made of SiN.

[0023] In combination with the second aspect, in certain implementations of the second aspect, the third optical signal is also coupled and transmitted from the third waveguide to the fourth waveguide through a waveguide conversion structure, the waveguide conversion structure includes a first part and a second part, the first part is coupled and connected to at least one DeMux through the third waveguide, the second part is coupled and connected to the photodetector array through the fourth waveguide, and the first part and the third waveguide are made of SiN.

[0024] In combination with the second aspect, in some implementations of the second aspect, the second portion of the waveguide conversion structure and the fourth waveguide are made of silicon Si.

[0025] In conjunction with the second aspect, in some implementations of the second aspect, the DeMux includes M stages of cascaded filter units, and the i-th stage of cascaded filter units includes 2 i Directionally coupled Mach-Zehnder interferometer DCMZI or 2 i A micro-ring assisted Mach-Zehnder interferometer RMZI is provided, wherein the DCMZI includes N repeated DCMZI filter structures, the DCMZI filter structure includes two waveguide arms, and the RMZI includes L repeated RMZI filter structures, the RMZI filter structure includes a micro-ring resonant cavity, M, N, L are positive integers, i∈[1,M].

[0026] It should be understood that at this time, the third optical signal includes 2 M single wavelength optical signals of different wavelengths.

[0027] In combination with the second aspect, in some implementations of the second aspect, the DeMux is an arrayed waveguide grating AWG filter, the AWG filter includes an output port and an array waveguide, the third optical signal is output from the output port, and the third optical signal includes K single-wavelength optical signals of different wavelengths.

[0028] In conjunction with the second aspect, in some implementations of the second aspect, the DeMux further includes 2 M An arrayed waveguide grating AWG filter is connected to the M-th cascaded filter unit in the M-th cascaded filter unit. Each AWG filter includes an output port and an arrayed waveguide. The third optical signal is output from the output port. The third optical signal includes K·2 M single wavelength optical signals of different wavelengths.

[0029] In a third aspect, a method for manufacturing an optical chip is provided, the method comprising: providing a silicon-on-insulator substrate SOI, the SOI comprising a silicon substrate and an oxide layer; setting an optical port, a polarization beam splitter rotator PSR and at least one wavelength demultiplexer DeMux in the oxide layer; making a photodetector array on the silicon substrate; wherein the optical port, the PSR and at least one DeMux are made of silicon nitride SiN, the optical port is coupled to an optical fiber, and is used to receive a first optical signal from the optical fiber, the first optical signal comprising a component of a transverse magnetic TM mode; the PSR is used to perform a first processing on the first optical signal to generate a second optical signal, the second optical signal is a transverse electric TE mode, and the second optical signal is a single-channel multi-wavelength optical signal; at least one DeMux is used to perform a second processing on the second optical signal to generate a third optical signal, the third optical signal is a multi-channel single-wavelength optical signal; the photodetector array is used to convert the third optical signal into an electrical signal.

[0030] In combination with the third aspect, in certain implementations of the third aspect, the method further includes: manufacturing a first waveguide and a second waveguide, the PSR is coupled to the optical port through the first waveguide, at least one DeMux is coupled to the PSR through the second waveguide, and the first waveguide and the second waveguide are made of SiN.

[0031] In combination with the third aspect, in certain implementations of the third aspect, the method further includes: manufacturing a third waveguide, the photodetector array and at least one DeMux are connected through the third waveguide, and the third waveguide is made of SiN.

[0032] In combination with the third aspect, in certain implementations of the third aspect, the method further includes: setting a waveguide conversion structure and making a fourth waveguide; wherein the waveguide conversion structure is used to couple and transmit the third optical signal from the third waveguide to the fourth waveguide, and includes a first part and a second part, wherein the first part is coupled to at least one DeMux through the third waveguide, and the second part is coupled to the photodetector array through the fourth waveguide, and the first part and the third waveguide are made of SiN.

[0033] In combination with the third aspect, in some implementations of the third aspect, the second portion of the waveguide conversion structure and the fourth waveguide are made of silicon Si.

[0034] In conjunction with the third aspect, in some implementations of the third aspect, the DeMux includes M stages of cascaded filter units, and the i-th stage of cascaded filter units includes 2 i Directionally coupled Mach-Zehnder interferometer DCMZI or 2 i A micro-ring assisted Mach-Zehnder interferometer RMZI is provided, wherein the DCMZI includes N repeated DCMZI filter structures, the DCMZI filter structure includes two waveguide arms, and the RMZI includes L repeated RMZI filter structures, the RMZI filter structure includes a micro-ring resonant cavity, M, N, L are positive integers, i∈[1,M].

[0035] In combination with the third aspect, in certain implementations of the third aspect, the DeMux is an arrayed waveguide grating AWG filter, the AWG filter includes an output port and an array waveguide, the third optical signal is output from the output port, and the third optical signal includes K single-wavelength optical signals of different wavelengths.

[0036] In conjunction with the third aspect, in some implementations of the third aspect, the DeMux further includes 2 M An arrayed waveguide grating AWG filter is connected to the M-th cascaded filter unit in the M-th cascaded filter unit. Each AWG filter includes an output port and an arrayed waveguide. The third optical signal is output from the output port. The third optical signal includes K·2 M single wavelength optical signals of different wavelengths.

[0037] In combination with the third aspect, in certain implementations of the third aspect, the photodetector array adopts at least one structure of a PN junction photodiode PNPD, a PIN photodiode PIN PD, an avalanche diode APD, a single photon avalanche diode SPAD, a Schottky barrier diode SBD and a silicon photomultiplier tube SiPM.

[0038] In combination with the third aspect, in certain implementations of the third aspect, the method further includes: setting at least one of a semiconductor optical amplifier SOA, a laser diode LD, a modulator, a heater heater, a variable optical attenuator VOA, and a multiplexer Mux.

[0039] In a fourth aspect, an optical module is provided, comprising: a housing; a substrate; an electrical chip for generating or processing radio frequency signals, located on the substrate; the optical chip in the first aspect and its possible implementation methods, located on the substrate; and a signal line, located on the substrate, for transmitting radio frequency signals between the electrical chip and the optical chip.

[0040] In a fifth aspect, a communication device is provided, which includes: a receiver including the optical module in the fourth aspect; and / or a transmitter including the optical module in the fourth aspect.

[0041] In a sixth aspect, a communication device is provided, which includes: a transceiver for receiving or sending a signal, the transceiver includes the optical module in the fourth aspect, the optical module is used to modulate or demodulate the signal; and a processor is used to process the signal.

[0042] Specifically, the beneficial effects of other aspects can refer to the beneficial effects described in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a layout diagram of an implementation method of an optical decomposition and multiplexing receiving chip provided in an embodiment of the present application;

[0044] Figure 2 It is a layout diagram of another optical decomposition and demultiplexing receiving chip implementation method provided in an embodiment of the present application;

[0045] Figure 3 is a cross-sectional schematic diagram of an optical decomposition and demultiplexing receiving chip provided in an embodiment of the present application;

[0046] Figure 4 It is a top view and a side view of a possible implementation of a waveguide conversion structure provided in an embodiment of the present application;

[0047] Figure 5 This is a schematic diagram of the structure of a wavelength demultiplexer provided in an embodiment of the present application;

[0048] Figure 6 This is a schematic diagram of a spectrum output by a wavelength demultiplexer provided in an embodiment of the present application;

[0049] Figure 7 This is a schematic diagram of another wavelength demultiplexer structure provided in an embodiment of the present application;

[0050] Figure 8 is a schematic diagram of a spectrum output by another wavelength demultiplexer provided in an embodiment of the present application;

[0051] Fig. 9 This is a schematic diagram of another wavelength demultiplexer structure provided in an embodiment of the present application;

[0052] Fig.10 This is a schematic diagram of another wavelength demultiplexer structure provided in an embodiment of the present application;

[0053] Fig.11 This is a schematic diagram of another wavelength demultiplexer structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0054] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0055] First, the terms "including" and "having" and any variations thereof in the embodiments of the present application shown below are intended to cover non-exclusive inclusions. For example, a system, product or device comprising a series of units is not necessarily limited to those units explicitly listed, but may include other units that are not explicitly listed or inherent to these products or devices.

[0056] Second, in the embodiments of the present application, words such as "exemplarily" or "for example" are used to indicate examples, illustrations or descriptions, and the embodiments or designs described as "exemplarily" or "for example" should not be interpreted as being more preferred or more advantageous than other embodiments or designs. The use of words such as "exemplarily" or "for example" is intended to present related concepts in a specific way for easy understanding.

[0057] Third, the terms "first", "second", etc. and various digital numbers in the text description or drawings of the embodiments of the present application shown below are merely distinctions for the convenience of description and do not have to be used to describe a specific order or sequence and are not used to limit the scope of the embodiments of the present application.

[0058] The optical path of the waveguide chip is manufactured using integrated circuit technology, and various functions of conventional discrete optical components are integrated into the surface of the same optical substrate, completing the optical information processing capabilities of a large optical system composed of multiple discrete optical components, and realizing functions such as light wave signal production and detection, optical power distribution, optical switching, and optical filtering. With the rapid development of optical fiber communication technology, this technology has also developed rapidly and gradually formed its own characteristics. Most of the functional structures are on the same optical substrate, and the main structure is the optical waveguide channel, so this technology is called planar lightwave circuit (PLC).

[0059] Planar optical waveguide technology is developed on the basis of integrated circuit technology and has its own unique features. The basic components of integrated circuits are resistors, capacitors, inductors and transistors (diodes, triodes). Integrated circuit technology is to make these basic components on silicon substrates through thin film deposition, diffusion, epitaxy, photolithography, etching, annealing and other processes, and interconnect them with wires. The basic components of planar optical waveguides are lasers, optical waveguides and detectors. The substrate materials used are different, such as III-V compound semiconductors (InP and GaAs), silicon dioxide (SiO2), lithium niobate (LiNbO3), silicon-on-insulator substrate SOI, polymer, glass, etc. Due to the different materials, there are many types of manufacturing processes.

[0060] Planar optical waveguide devices are devices made using planar optical waveguide technology, and are divided into passive devices, active devices, and active / passive hybrid integrated devices. Among them, passive devices can be understood as devices that do not require energy (electricity) and can be used to achieve functions such as transmission, splitting, combining, and filtering of optical wave signals. Passive devices mainly include planar optical waveguide splitters, arrayed waveguide gratings (AWG), optical filters, etc.

[0061] In a possible implementation, discrete AWGs can be used to assemble a wavelength division multiplexing receiving optoelectronic chip through patches, and the wavelength division multiplexing function can be realized using the AWG made of Si material. The light output by the AWG is coupled into the vertical structure PD through mirror reflection.

[0062] It should be understood that the optical chip manufacturing process in the above implementation has low precision, large device size, low device yield, high cost, large coupling loss from PLC to PD, and reduced sensitivity of the receiving optical sub-assembly (ROSA) when the wavelength is at the sideband position.

[0063] In another possible implementation, a CWDM4 chip is integrated based on an SOI platform, and an EDG filter made of Si material is used in the receiving optical chip to realize wavelength division multiplexing / demultiplexing functions, filtering the incident multiple wavelengths into 4 channels; a waveguide-coupled vertical Ge PD photodetector is used to realize photoelectric conversion, and the optical chip is insensitive to polarization.

[0064] The optical chip manufacturing process in the above implementation has low precision, the EDG insertion loss is large, the EDG is sensitive to temperature and requires a cooler to control temperature drift, the 1dB passband of the filter spectrum is narrow, and the flat top is narrow.

[0065] It should be understood that the use of Si materials to prepare DeMux has large insertion loss, high temperature drift coefficient, requires temperature refrigeration control, and is costly. Based on the above problems, the present application provides the following embodiments, using SiN-SOI hybrid integration, passive devices such as DeMux made of SiN materials, and active photodetectors with excellent performance made through a CMOS-compatible SOI platform, so as to realize on-chip integration of low-loss wavelength division multiplexing receiving optical chips without cooling.

[0066] Figure 1 1 is a layout diagram of an optical demultiplexing receiving chip implementation method provided by the present application. Figure 1 As shown, the optical chip at least includes the following parts:

[0067] The optical port 100 is coupled to the optical fiber and is used to receive a first optical signal from the optical fiber.

[0068] The optical port may also be called an optical coupler, an optical port coupling structure, an optical input port, or an optical fiber end face coupler, etc., and this application does not impose any limitation on this.

[0069] Polarization splitter and rotators 200 (PSR), PSR200 is used to perform a first processing on the input first optical signal to generate a second optical signal. The second optical signal is a transverse electric (TE) mode. Specifically, the input non-single polarized light is split into two polarized lights with orthogonal polarization states, and one polarization state is converted into another polarization state, for example, the input transverse magnetic (TM) mode optical signal is converted into a TE mode optical signal.

[0070] The PSR 200 realizes mode polarization rotation of input light, converts the input TM mode optical signal into a TE mode optical signal, and outputs it from one of the ports; while the TE mode optical signal maintains TE mode transmission and is output from the other port.

[0071] At least one wavelength demultiplexer (DeMux) 300 is used to perform a second processing on the second optical signal to generate a third optical signal, and the third optical signal is a multi-channel single-wavelength optical signal, that is, a single-channel multi-wavelength optical signal is processed to obtain a multi-channel single-wavelength optical signal. DeMux 300 can filter the multi-wavelength optical signal input by a single channel and output it from different channels respectively, and the wavelength interval between channels is adjustable, and meets the coarse wavelength division multiplexing (CWDM) application standard and the fine wavelength division multiplexing (LWDM) application standard.

[0072] In one possible implementation, Figure 1 As shown in the figure, the two ports of PSR 200 carry the TE and TM signal components of the original optical signal respectively. Therefore, the two ports need to be connected to a set of identical DeMux respectively. The two sets of DeMux are then connected to the PD of the same channel. The photocurrents are added in parallel at the PD to achieve complete photoelectric conversion of the original optical signal.

[0073] In another possible implementation, the two ports of PSR 200 carry the TE and TM signal components of the original optical signal respectively, and then the two TE beams are directly combined through the device, so that only one DeMux can be connected. Or if the polarization balance of the receiving end responsivity is not considered, then either the TE path or the TM path can be connected to the DeMux.

[0074] The photodetector array 700 is used to convert optical signals into electrical signals.

[0075] The photodetector array 700 can be a PN junction photodiode, a PIN photodiode (PIN photodiode, PIN-PD), an avalanche diode (avalanche photodiode, APD), a single photonavalanche diode (single photonavalanche diode, SPAD), a Schottky barrier diode (schottky barrier diode, SBD) and a silicon photomultiplier (silicon photomultiplier, SiPM), etc., or it can be a combination of multiple sensor devices. The present application does not limit this. The function of converting optical signals into electrical signals shall prevail. Similar devices or combinations of devices should be within the scope of protection of the present application.

[0076] The optical port 100 and the PSR 200 are coupled and connected via a first waveguide 410 , the PSR 200 and the DeMux 300 are coupled and connected via a second waveguide 420 , and the DeMux 300 and the photodetector array 700 are coupled and connected via a third waveguide 430 . The waveguides are used for coupling and transmitting optical signals between devices.

[0077] Figure 2 FIG. 1 is a layout diagram of another optical demultiplexing receiving chip implementation method provided by the present application. Figure 2 As shown, the optical chip also includes:

[0078] The waveguide conversion structure 500 is used to couple and transmit the optical signal from the third waveguide 420 to the fourth waveguide 600. The waveguide conversion structure 500 is connected to the photodetector array 700 through the fourth waveguide 600, and the fourth waveguide 600 is used for coupling and transmitting the optical signal therebetween.

[0079] Figure 3 It is a cross-sectional schematic diagram of an optical decomposition and multiplexing receiving chip provided by the present application.

[0080] like Figure 3 As shown, the optical chip includes a substrate 800, which is made of silicon Si material. An oxide layer 900 is arranged on the substrate 800, and the oxide layer 900 is made of silicon dioxide SiO2. The oxide layer can also be called a buried oxide layer.

[0081] The optical port 100, PSR200 and DeMux300 are made of silicon nitride SiN material and are arranged in the oxide layer 900. The optical port 100 and PSR 200 are coupled and connected through the first waveguide 410, the PSR 200 and DeMux 300 are coupled and connected through the second waveguide 420, and the DeMux 300 and the photodetector array 700 are coupled and connected through the third waveguide 430. The first waveguide 410, the second waveguide 420 and the third waveguide 430 are made of SiN and can be called SiN waveguides.

[0082] Compared with Si waveguide, SiN waveguide has the following advantages: the refractive index of SiN is smaller than that of Si, and the refractive index contrast of the waveguide formed by SiN and the oxide layer is small. The waveguide size is larger, so its sensitivity to the waveguide thickness is reduced, and the yield of the device can be improved; SiN has a smaller thermo-optical coefficient, which is one order of magnitude smaller than Si, and the impact of temperature changes is greatly reduced; SiN waveguide can reduce the complexity of the optical path and reduce the chip size; SiN waveguide has reduced transmission loss, which can further reduce on-chip loss.

[0083] The fourth waveguide 600 may also be referred to as an SOI waveguide. The structure of the SOI waveguide may be a strip waveguide, a large cross-sectional area ridge waveguide, a slot waveguide, a photonic crystal (PhC) waveguide, a sub-wavelength grating (SWG) waveguide, a sub-wavelength grating slot (SWGS) waveguide, or a surface plasmon slot (SPP-slot) waveguide, etc., which is not limited in the present application.

[0084] In order to connect waveguides made of different materials, a waveguide conversion structure 500 is provided, which is made of SiN material and SOI material from top to bottom in the vertical direction, so that the optical signal is coupled and transmitted from the third waveguide 430 to the fourth waveguide 600.

[0085] Figure 4 These are a top view and a side view of a possible implementation of a waveguide conversion structure provided in the present application.

[0086] like Figure 4 As shown in the top view (a), the first part of the waveguide conversion structure 500 is made of SiN material, and the second part is made of Si material. The shadows of the first part and the second part overlap at the transition point, so that the SiN waveguide and the Si waveguide are evanescently coupled, and the effective refractive index of the waveguide is controlled by the waveguide cross section, so that the optical signal is gradually coupled from the SiN waveguide into the Si waveguide. Figure 4 (b) side view, the SiN material and the SOI material do not need to be in contact, that is, there can be a certain gap between the two. The first part and the second part of the waveguide conversion structure 500 can be as follows Figure 3The gradually narrowing strip shape shown in the figure may also be other shapes such as a triangle. The present application does not limit the specific shape of the waveguide conversion structure 500.

[0087] In one possible implementation, Figure 1 In the implementation method in, the waveguide conversion structure may not be used. In this case, SiN is directly coupled to the waveguide (such as Si-Ge) of the PD at the photodetector array, and the third waveguide and the fourth waveguide are the same.

[0088] The photodetector array 700 is made of semiconductor materials grown by selective epitaxial growth on an SOI substrate, including but not limited to germanium Ge, indium gallium arsenide InGaAs, gallium phosphide GaP, and silicon Si. Figure 3 The growth process of the PD semiconductor material can be epitaxy or other processes, which is not limited in this application.

[0089] In a possible implementation, the photodetector array 700 may be a Ge PD array structure, consisting of four channels of Ge PD, each PD having a Ge absorption region connected by a PIN junction and electrical interconnection to achieve photoelectric conversion. The Ge PD of each channel may adopt a lateral PIN structure or a vertical PIN structure.

[0090] It should be understood that the Ge PD of each channel may also be formed by connecting a plurality of PDs in parallel, or may also be implemented using an APD structure.

[0091] Arbitrary polarization multi-wavelength light is input from the optical port 100, and the input TM mode light is converted into TE mode light by PSR200 and output from one of the ports; the TE mode light remains in TE mode and is output from the other port. Then, filtering is performed by DeMux300 to realize multi-channel single-wavelength optical signals with a channel spacing of Δλnm. After the light from each output port passes through the SiN-SOI waveguide conversion structure 500, it is optically coupled to the SOI second waveguide 600, and is coupled into the Ge PD photodetector array 700 to realize photoelectric conversion and convert the optical signal into an electrical signal.

[0092] The present application provides various structures of wavelength demultiplexer DeMux300.

[0093] In one possible implementation, Figure 5 As shown, DeMux300 is implemented by a directional coupler mach zender interferometer (DCMZI) filter. DeMux300 includes M stages of cascaded DCMZI filter units, and the i-th stage includes 2 icascaded DCMZI filter units, each DCMZI unit may include N DCMZI filter structures, each DCMZI filter structure includes two waveguide arms, a total of 2 M Output ports, can output 2 M optical signals of different wavelengths, 2 M The wavelength interval of optical signals of different wavelengths is Δλnm.

[0094] It should be understood that the optical signal can be filtered by the optical path difference of the two waveguide arms of the DCMZI filtering structure. The length of the waveguide arm in the drawings of the present application is only a comparative schematic diagram, and the present application does not limit the specific length of the waveguide arm.

[0095] For example, the optical signal may be an optical signal including four wavelengths of λ0, λ1, λ2, and λ3. The optical signal can achieve filtering with a wavelength interval of Δλnm through the first-stage cascaded DCMZI filter unit. To achieve a higher extinction ratio (ER), the cascaded DCMZI filter unit may also adopt a multiple-repetition structure. Through two second-stage cascaded DCMZI filter units, filtering with a wavelength interval of 2Δλnm can be achieved. To achieve a higher ER, the second-stage cascaded DCMZI filter unit may also adopt a multiple-repetition structure. Finally, filtering with a wavelength interval of Δλnm is achieved, and light of different wavelengths λ0, λ1, λ2, and λ3 are output from four ports respectively. The spectrum is as follows: Figure 6 As shown, the loss of multiple wavelengths with an interval of Δλnm is small.

[0096] In another possible implementation, Figure 7 As shown, DeMux300 is implemented by a micro-ring assisted Mach-Zehnder interferometer (RMZI) filter. DeMux300 includes M-stage cascaded RMZI filter units, and the i-th stage includes 2 i cascaded RMZI filter units, each RMZI unit may include L RMZI filter structures, each RMZI filter structure includes a micro-ring resonant cavity, a total of 2 M Output ports, can output 2 M optical signals of different wavelengths, 2 M The wavelength interval of optical signals of different wavelengths is Δλnm.

[0097] It should be understood that RMZI uses a micro-ring resonator to enhance the filtering characteristics based on MZI. The beam splitter and beam combiner in RMZI can be directional coupler (DC), Y-branch, multimode interference coupler (MMI), trident type, etc. The DC structure of the beam splitter and beam combiner in the drawings of this application is only a schematic diagram, and this application does not limit the structure of the beam splitter and beam combiner in RMZI.

[0098] For example, the optical signal may be an optical signal including four wavelengths of λ0, λ1, λ2, and λ3. The optical signal can achieve filtering with a wavelength interval of Δλnm through the first-stage cascaded RMZI filter unit. To achieve a higher ER, the cascaded RMZI filter unit may also adopt a multiple-repetition structure. Through two second-stage cascaded RMZI filter units, filtering with a wavelength interval of 2Δλnm can be achieved. To achieve a higher ER, the second-stage cascaded RMZI filter unit may also adopt a multiple-repetition structure. Finally, filtering with a wavelength interval of Δλnm is achieved, and light of different wavelengths λ0, λ1, λ2, and λ3 are output from four ports respectively. The spectrum is as follows Figure 8 As shown, the loss of multiple wavelengths with an interval of Δλnm is small.

[0099] DCMZI and RMZI can be used separately or simultaneously.

[0100] In another possible implementation, Fig. 9 As shown, DeMux 300 is implemented by a combination of RMZI filters and / or DCMZI filters. DeMux 300 includes M-stage cascaded filter units, and the i-th stage includes 2 i cascaded RMZI or DCMZI filter units, each RMZI unit may include L RMZI filter structures, each RMZI filter structure includes a microring resonant cavity, each DCMZI unit may include N DCMZI filter structures, each DCMZI filter structure includes two waveguide arms, a total of 2 M Output ports, can output 2 M optical signals of different wavelengths, 2 M The wavelength interval of optical signals of different wavelengths is Δλnm.

[0101] For example, the optical signal may be an optical signal including four wavelengths of λ0, λ1, λ2, and λ3. The optical signal can achieve filtering with a wavelength interval of Δλnm through the first-stage cascaded RMZI filter unit. To achieve a higher ER, the cascaded RMZI filter unit may also adopt a multiple-repetition structure. Through two second-stage cascaded DCMZI filter units, filtering with a wavelength interval of 2Δλnm can be achieved. To achieve a higher ER, the second-stage cascaded DCMZI filter unit may also adopt a multiple-repetition structure. Finally, filtering with a wavelength interval of Δλnm is achieved, and light of different wavelengths λ0, λ1, λ2, and λ3 are output from four ports respectively.

[0102] To achieve filtering of more channels, DeMux300 can be implemented by any combination of M-level cascaded DCMZI or RMZI filter structures, such as Fig.10 As shown, each level of cascaded DCMZI filters can be composed of multiple DCMZI cascades, and each level of cascaded RMZI filters can be composed of multiple RMZI cascades, ultimately achieving filtering with a wavelength interval of Δλnm, and light of different wavelengths is respectively transmitted from 2 M port output.

[0103] In another possible implementation, Fig.11 As shown in (a), DeMux 300 can be implemented by using an AWG filter made of SiN material. Filtering with a wavelength interval of Δλnm can be achieved, and lights of different wavelengths are output from K ports respectively.

[0104] To achieve filtering of more channels, DeMux300 can be realized by combining cascaded DCMZI or RMZI filter structures with AWG filters, such as Fig.11 As shown in (b), DeMux300 includes M-stage cascaded filter units, and the i-th stage includes 2 i The invention provides a cascaded RMZI or DCMZI filter unit, each RMZI unit may include L RMZI filter structures, each RMZI filter structure includes a micro-ring resonant cavity, each DCMZI unit may include N DCMZI filter structures, each DCMZI filter structure includes two waveguide arms, and is connected to the M-th filter unit by 2 M AWG filter structures, each AWG filter structure includes K output ports, so DeMux300 has a total of K·2 M Output ports, can output K·2 M optical signals of different wavelengths, K·2 M The wavelength interval of optical signals of different wavelengths is Δλnm.

[0105] The size of the wavelength interval Δλnm of the multi-wavelength light can be controlled by adjusting the specific structure of the RMZI filter, the cascaded DCMZI filter or the SiN AWG filter, and the specific adjustment method is not limited in this application.

[0106] Through the solution of the present application, the SiN material DeMux device is implemented using an RMZI filter, a cascaded DCMZI filter or a SiN AWG filter, which can realize the wavelength division multiplexing function without the need for an additional cooler and has low optical transmission loss.

[0107] The optical chip provided in the present application can also be integrated on-chip with a laser diode (LD), a modulator, a heater, a semiconductor optical amplifier (SOA), a variable optical attenuator (VOA) and a multiplexer Mux to realize an on-chip integrated optical chip with integrated transmission / reception.

[0108] In a possible implementation, a SOA device may be provided between the optical port 100 and the DeMux 300. When used in a scene with weak light intensity, the SOA device plays a role of light amplification.

[0109] In a possible implementation, a VOA may be provided between the optical port 100 and the DeMux 300. In contrast to the SOA, the VOA is used when the light intensity at the receiving end is relatively large, and the VOA device plays a role of optical attenuation.

[0110] In a possible implementation, LD, modulator, heater, and Mux can constitute the transmitting component. Among them, LD is the light source at the transmitting end, and the modulator is an electro-optical modulator, which converts the electrical signal into an optical signal and transmits it to the Mux for wave combination through a waveguide, and finally outputs it to the outside of the chip through an optical port. The heater achieves waveguide phase modulation by changing the temperature through heating, and then adjusts the filtering characteristics of the DeMux and Mux to achieve the desired passband. Among them, the heater or other phase shifter at the transmitting end is mainly used to adjust the initial phase of the modulator to achieve the desired operating point.

[0111] According to the aforementioned optical chip, the present application provides an optical signal transmission method.

[0112] The method comprises at least the following steps:

[0113] The first optical signal enters the optical chip from the optical fiber through the optical port, the optical port is coupled to the optical fiber, and the first optical signal includes a component of the transverse magnetic TM mode; the first optical signal is first processed by the PSR to generate a second optical signal, the second optical signal is a transverse electric TE mode, and the second optical signal is a single-channel multi-wavelength optical signal.

[0114] The first optical signal includes a TM mode component and a TE mode component. When passing through the PSR, the input TM mode optical signal is converted into a TE mode optical signal and output from one of the ports; while the TE mode optical signal maintains TE mode transmission and is output from the other port.

[0115] The second optical signal is subjected to a second processing by at least one DeMux to generate a third optical signal, which is a multi-channel single-wavelength optical signal; the third optical signal is converted into an electrical signal by a photodetector array; wherein the optical port, the PSR and at least one DeMux are made of silicon nitride SiN.

[0116] In a possible implementation, the PSR is coupled to the optical port via a first waveguide, and at least one DeMux is coupled to the PSR via a second waveguide, and the first waveguide and the second waveguide are made of SiN.

[0117] The photodetector array is connected to at least one DeMux via a third waveguide, which is made of SiN.

[0118] In a possible implementation manner, the third optical signal is also coupled and transmitted from the third waveguide to the fourth waveguide through the waveguide conversion structure.

[0119] The waveguide conversion structure comprises a first part and a second part, the first part is coupled to at least one DeMux via a third waveguide, the second part is coupled to the photodetector array via a fourth waveguide, and the first part and the third waveguide are made of SiN.

[0120] The second part of the waveguide conversion structure and the fourth waveguide are made of silicon Si.

[0121] In a possible implementation, the DeMux includes M stages of cascaded filter units, and the i-th stage of cascaded filter units includes 2 i DCMZI or 2 i The DCMZI includes N repeated DCMZI filter structures, the DCMZI filter structure includes two waveguide arms, the RMZI includes L repeated RMZI filter structures, the RMZI filter structure includes a microring resonant cavity, M, N, L are positive integers, i∈[1,M].

[0122] The third optical signal includes 2 M single wavelength optical signals of different wavelengths.

[0123] In one possible implementation, DeMux also includes 2 MAn AWG filter is connected to the M-th cascaded filter unit in the M-th cascaded filter unit, each AWG filter includes an output port and an array waveguide, the third optical signal is output from the output port, and the third optical signal includes K·2 M single wavelength optical signals of different wavelengths.

[0124] In a possible implementation manner, the DeMux is an AWG filter, the AWG filter includes an output port and an array waveguide, the third optical signal is output from the output port, and the third optical signal includes K single-wavelength optical signals with different wavelengths.

[0125] Based on the aforementioned optical chip, the present application also provides a method for manufacturing an optical chip.

[0126] The method comprises: providing a silicon-on-insulator substrate SOI, wherein the SOI comprises a silicon substrate and an oxide layer; arranging an optical port, a polarization beam splitter rotator PSR and at least one wavelength demultiplexer DeMux in the oxide layer; and manufacturing a photodetector array on the silicon substrate; wherein the optical port, the PSR and at least one DeMux are made of SiN,

[0127] The optical port is coupled to the optical fiber and is used to receive a first optical signal from the optical fiber, wherein the first optical signal includes a component of a transverse magnetic TM mode; the PSR is used to perform a first processing on the first optical signal to generate a second optical signal, wherein the second optical signal is a transverse electric TE mode and is a single-channel multi-wavelength optical signal; at least one DeMux is used to perform a second processing on the second optical signal to generate a third optical signal, wherein the third optical signal is a multi-channel single-wavelength optical signal; and the photodetector array is used to convert the third optical signal into an electrical signal.

[0128] This application does not limit the process of manufacturing optical ports, PSR and DeMux.

[0129] The photodetector array can be made on an SOI substrate by selective epitaxial growth of semiconductor materials, including but not limited to germanium Ge, indium gallium arsenide InGaAs, gallium phosphide GaP and silicon Si. The growth process of PD semiconductor materials can be epitaxy or other processes, which is not limited in this application.

[0130] In a possible implementation, a first waveguide and a second waveguide are manufactured, the PSR is coupled to the optical port through the first waveguide, at least one DeMux is coupled to the PSR through the second waveguide, and the first waveguide and the second waveguide are made of SiN.

[0131] In a possible implementation manner, a third waveguide is manufactured, and the photodetector array is connected to at least one DeMux via the third waveguide, and the third waveguide is made of SiN.

[0132] In one possible implementation, a waveguide conversion structure is provided, and a fourth waveguide is manufactured; wherein the waveguide conversion structure is used to couple and transmit the third optical signal from the third waveguide to the fourth waveguide, and comprises a first part and a second part, wherein the first part is coupled to at least one DeMux via the third waveguide, and the second part is coupled to the photodetector array via the fourth waveguide, and the first part and the third waveguide are made of SiN.

[0133] The second part of the waveguide conversion structure and the fourth waveguide are made of silicon Si.

[0134] In a possible implementation, the DeMux includes M stages of cascaded filter units, and the i-th stage of cascaded filter units includes 2 i DCMZI or 2 i The DCMZI includes N repeated DCMZI filter structures, the DCMZI filter structure includes two waveguide arms, the RMZI includes L repeated RMZI filter structures, the RMZI filter structure includes a microring resonant cavity, M, N, L are positive integers, i∈[1,M].

[0135] In one possible implementation, DeMux also includes 2 M an arrayed waveguide grating AWG filter, the AWG filter is connected to the M-th cascaded filter unit in the M-stage cascaded filter units, each AWG filter comprises an output port and an arrayed waveguide, the third optical signal is output from the output port, and the third optical signal comprises K·2 M single wavelength optical signals of different wavelengths.

[0136] In a possible implementation manner, the DeMux is an AWG filter, the AWG filter includes an output port and an array waveguide, the third optical signal is output from the output port, and the third optical signal includes K single-wavelength optical signals with different wavelengths.

[0137] In a possible implementation, the photodetector array adopts at least one structure selected from the group consisting of a PN junction photodiode PN PD, a PIN photodiode PINPD, an avalanche diode APD, a single photon avalanche diode SPAD, a Schottky barrier diode SBD, and a silicon photomultiplier tube SiPM.

[0138] In a possible implementation manner, at least one of a semiconductor optical amplifier SOA, a laser diode LD, a modulator, a heater heater, a variable optical attenuator VOA and a multiplexer Mux is provided.

[0139] An embodiment of the present application also provides an optical module, including: a shell; a substrate; an electrical chip for generating radio frequency signals or processing radio frequency signals, located on the substrate; the above-mentioned optical chip, located on the substrate; a signal line, located on the substrate, for transmitting radio frequency signals between the electrical chip and the optical chip.

[0140] An embodiment of the present application further provides a communication device, including: a receiver, including the above-mentioned optical module; and / or a transmitter, including the above-mentioned optical module.

[0141] An embodiment of the present application also provides a communication device, including: a transceiver, used to receive or send signals, the transceiver includes the above-mentioned optical module, the optical module is used to modulate or demodulate the signal; a processor, used to process the signal.

[0142] In the several embodiments provided in the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0143] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0144] It should be understood that different embodiments may be used independently or in combination based on certain internal or external connections, and different implementations in the embodiments may be used independently or in combination.

[0145] It should be understood that the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0146] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An optical chip, characterized in that: include: an optical port, coupled to the optical fiber, and configured to receive a first optical signal from the optical fiber, wherein the first optical signal includes a component of a transverse magnetic TM mode; a polarization beam splitter rotator PSR, configured to perform a first process on the first optical signal to generate a second optical signal, wherein the second optical signal is a transverse electric TE mode and is a single-channel multi-wavelength optical signal; at least one wavelength demultiplexer DeMux, configured to perform a second process on the second optical signal to generate a third optical signal, wherein the third optical signal is a multi-channel single-wavelength optical signal; A photodetector array is used to convert the third optical signal into an electrical signal; wherein The optical port, the PSR and the at least one DeMux are made of silicon nitride SiN.

2. The optical chip according to claim 1, characterized in that: The PSR is coupled to the optical port via a first waveguide, the at least one DeMux is coupled to the PSR via a second waveguide, and the first waveguide and the second waveguide are made of SiN.

3. The optical chip according to claim 2, characterized in that: The photodetector array is connected to the at least one DeMux via a third waveguide, and the third waveguide is made of SiN.

4. The optical chip according to claim 2, characterized in that: The optical chip further includes: a waveguide conversion structure for coupling and transmitting the third optical signal from the third waveguide to the fourth waveguide, The method comprises a first part and a second part, wherein the first part is coupled to the at least one DeMux through the third waveguide, the second part is coupled to the photodetector array through the fourth waveguide, and the first part and the third waveguide are made of SiN.

5. The optical chip according to claim 4, characterized in that: The second portion of the waveguide conversion structure and the fourth waveguide are made of silicon Si.

6. The optical chip according to any one of claims 1 to 5, characterized in that: The DeMux includes M levels of cascaded filter units, and the i-th level of cascaded filter units includes 2 i Directionally coupled Mach-Zehnder interferometer DCMZI or 2 i A micro-ring assisted Mach-Zehnder interferometer RMZI is provided, wherein the DCMZI comprises N repeated DCMZI filter structures, wherein the DCMZI filter structure comprises two waveguide arms, and the RMZI comprises L repeated RMZI filter structures, wherein the RMZI filter structure comprises a micro-ring resonant cavity, wherein M, N, and L are positive integers, and i∈[1, M].

7. The optical chip according to claim 6, characterized in that: The third optical signal includes 2 M single wavelength optical signals of different wavelengths.

8. The optical chip according to any one of claims 1 to 5, characterized in that: The DeMux is an array waveguide grating AWG filter, the AWG filter comprises an output port and an array waveguide, the third optical signal is output from the output port, and the third optical signal comprises K single-wavelength optical signals with different wavelengths.

9. The optical chip according to claim 6, characterized in that: The DeMux also includes 2 M an arrayed waveguide grating AWG filter, the AWG filter is connected to the M-th cascaded filter unit in the M-stage cascaded filter units, each AWG filter comprises an output port and an arrayed waveguide, the third optical signal is output from the output port, and the third optical signal comprises K·2 M single wavelength optical signals of different wavelengths.

10. The optical chip according to any one of claims 1 to 9, characterized in that: The photodetector array adopts at least one structure of a PN junction photodiode PNPD, a PIN photodiode PIN PD, an avalanche diode APD, a single photon avalanche diode SPAD, a Schottky barrier diode SBD and a silicon photomultiplier tube SiPM.

11. The optical chip according to any one of claims 1 to 10, characterized in that: The photodetector array is a detector made of semiconductor material epitaxially grown on silicon on insulator (SOI).

12. The optical chip according to any one of claims 1 to 11, characterized in that: The optical chip further includes at least one of a semiconductor optical amplifier SOA, a laser diode LD, a modulator, a heater heater, a variable optical attenuator VOA and a multiplexer Mux.

13. A method for transmitting an optical signal, characterized in that: include: A first optical signal enters the optical chip from the optical fiber through an optical port, the optical port is coupled to the optical fiber, and the first optical signal includes a component of a transverse magnetic TM mode; The first optical signal is first processed by a polarization beam splitter rotator PSR to generate a second optical signal, wherein the second optical signal is a transverse electric TE mode and is a single-channel multi-wavelength optical signal; The second optical signal is subjected to a second process by at least one wavelength demultiplexer DeMux to generate a third optical signal, wherein the third optical signal is a multi-channel single-wavelength optical signal; The third optical signal is converted into an electrical signal by a photodetector array; wherein The optical port, the PSR and the at least one DeMux are made of silicon nitride SiN.

14. The method according to claim 13, characterized in that The PSR is coupled to the optical port via a first waveguide, the at least one DeMux is coupled to the PSR via a second waveguide, and the first waveguide and the second waveguide are made of SiN.

15. The method according to claim 14, characterized in that The photodetector array is connected to the at least one DeMux via a third waveguide, and the third waveguide is made of SiN.

16. The method according to claim 14, characterized in that The third optical signal is also coupled and transmitted from the third waveguide to the fourth waveguide through a waveguide conversion structure, wherein the waveguide conversion structure includes a first part and a second part, wherein the first part is coupled and connected to the at least one DeMux through the third waveguide, and the second part is coupled and connected to the photodetector array through the fourth waveguide, and the first part and the third waveguide are made of SiN.

17. The method according to claim 16, characterized in that The second portion of the waveguide conversion structure and the fourth waveguide are made of silicon Si.

18. The method according to any one of claims 13 to 17, characterized in that The DeMux includes M levels of cascaded filter units, and the i-th level of cascaded filter units includes 2 i Directionally coupled Mach-Zehnder interferometer DCMZI or 2 i A micro-ring assisted Mach-Zehnder interferometer RMZI is provided, wherein the DCMZI comprises N repeated DCMZI filter structures, wherein the DCMZI filter structure comprises two waveguide arms, and the RMZI comprises L repeated RMZI filter structures, wherein the RMZI filter structure comprises a micro-ring resonant cavity, wherein M, N, and L are positive integers, and i∈[1, M].

19. The method according to claim 18, characterized in that The third optical signal includes 2 M single wavelength optical signals of different wavelengths.

20. The method according to any one of claims 13 to 17, characterized in that The DeMux is an array waveguide grating AWG filter, the AWG filter comprises an output port and an array waveguide, the third optical signal is output from the output port, and the third optical signal comprises K single-wavelength optical signals with different wavelengths.

21. The method according to claim 18, characterized in that The DeMux also includes 2 M an arrayed waveguide grating AWG filter, the AWG filter is connected to the M-th cascaded filter unit in the M-stage cascaded filter units, each AWG filter comprises an output port and an arrayed waveguide, the third optical signal is output from the output port, and the third optical signal comprises K·2 M single wavelength optical signals of different wavelengths.

22. A method for manufacturing an optical chip, characterized in that: include: Providing a silicon-on-insulator (SOI) substrate, wherein the SOI comprises a silicon substrate and an oxide layer; An optical port, a polarization beam splitter rotator PSR and at least one wavelength demultiplexer DeMux are arranged in the oxide layer; A photodetector array is fabricated on the silicon substrate; wherein the optical port, the PSR and the at least one DeMux are made of silicon nitride SiN, The optical port is coupled to the optical fiber and is used to receive a first optical signal from the optical fiber, wherein the first optical signal includes a component of a transverse magnetic TM mode; The PSR is used to perform a first processing on the first optical signal to generate a second optical signal, wherein the second optical signal is a transverse electric TE mode, and the second optical signal is a single-channel multi-wavelength optical signal; The at least one DeMux is used to perform a second process on the second optical signal to generate a third optical signal, wherein the third optical signal is a multi-channel single-wavelength optical signal; The photodetector array is used to convert the third optical signal into an electrical signal.

23. The method according to claim 22, characterized in that The method further includes: manufacturing a first waveguide and a second waveguide, wherein the PSR is coupled to the optical port through the first waveguide, and the at least one DeMux is coupled to the PSR through the second waveguide, and the first waveguide and the second waveguide are made of SiN.

24. The method according to claim 23, characterized in that The method further includes: manufacturing a third waveguide, the photodetector array and the at least one DeMux are connected through the third waveguide, and the third waveguide is made of SiN.

25. The method according to claim 23, characterized in that The method also includes: setting a waveguide conversion structure and making a fourth waveguide; wherein the waveguide conversion structure is used to couple and transmit the third optical signal from the third waveguide to the fourth waveguide, and includes a first part and a second part, the first part is coupled and connected with the at least one DeMux through the third waveguide, the second part is coupled and connected with the photodetector array through the fourth waveguide, and the first part and the third waveguide are made of SiN.

26. The method according to claim 25, characterized in that The second portion of the waveguide conversion structure and the fourth waveguide are made of silicon Si.

27. The method according to any one of claims 22 to 26, characterized in that The DeMux includes M levels of cascaded filter units, and the i-th level of cascaded filter units includes 2 i Directionally coupled Mach-Zehnder interferometer DCMZI or 2 i A micro-ring assisted Mach-Zehnder interferometer RMZI is provided, wherein the DCMZI comprises N repeated DCMZI filter structures, wherein the DCMZI filter structure comprises two waveguide arms, and the RMZI comprises L repeated RMZI filter structures, wherein the RMZI filter structure comprises a micro-ring resonant cavity, wherein M, N, and L are positive integers, and i∈[1, M].

28. The method according to any one of claims 22 to 26, characterized in that The DeMux is an array waveguide grating AWG filter, the AWG filter comprises an output port and an array waveguide, the third optical signal is output from the output port, and the third optical signal comprises K single-wavelength optical signals with different wavelengths.

29. The method according to claim 27, characterized in that The DeMux also includes 2 M an arrayed waveguide grating AWG filter, the AWG filter is connected to the M-th cascaded filter unit in the M-stage cascaded filter units, each AWG filter comprises an output port and an arrayed waveguide, the third optical signal is output from the output port, and the third optical signal comprises K·2 M single wavelength optical signals of different wavelengths.

30. The method according to any one of claims 22 to 29, characterized in that The photodetector array adopts at least one structure selected from the group consisting of a PN junction photodiode PN PD, a PIN photodiode PIN PD, an avalanche diode APD, a single photon avalanche diode SPAD, a Schottky barrier diode SBD and a silicon photomultiplier tube SiPM.

31. The method according to any one of claims 22 to 30, characterized in that The method further comprises: setting at least one of a semiconductor optical amplifier SOA, a laser diode LD, a modulator, a heater heater, a variable optical attenuator VOA and a multiplexer Mux.

32. An optical module, characterized in that: include: case; substrate; An electrical chip, used for generating radio frequency signals or processing radio frequency signals, located on the substrate; The optical chip according to any one of claims 1 to 12, located on the substrate; The signal line is located on the substrate and is used to transmit radio frequency signals between the electrical chip and the optical chip.

33. A communication device, characterized in that: include: A receiver comprising the optical module as claimed in claim 32; and / or A transmitter comprising the optical module as claimed in claim 32.

34. A communication device, characterized in that: include: A transceiver for receiving or sending a signal, the transceiver comprising an optical module as claimed in claim 32, the optical module being used for modulating or demodulating the signal; A processor is used to perform signal processing on the signal.

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