A method for realizing switchable filtering in free spectral range based on path selection optical path

Abstract

The present invention provides a method for realizing switchable filtering in a free spectral range based on a path selection optical path, preparing multiple parallel filters on a single chip, and controlling the path selection optical path through a chip integrated logic circuit to adjust the transmission path of the signal light field and pass it through different filters, thereby realizing programmable filtering with flexible switchable free spectral range of ITU standard frequency interval. The present invention solves the problem that traditional filters can only tune the central wavelength but cannot change the transmission spectrum, improves the flexibility of optoelectronic information systems in frequency domain processing, and provides an important solution for the research and development of optoelectronic information systems that can be logically programmed and software-defined.

Description

Technical Field

[0001] The present invention belongs to the interdisciplinary field of integrated optics, optical communications and microwave photonics, and specifically refers to a chip integrated filtering method that utilizes a path selection optical path to switch a signal light field transmission path and realize a switchable free spectral range, and more particularly to a method, system and storage medium for realizing switchable free spectral range filtering based on a path selection optical path. Background Art

[0002] Optoelectronic information system refers to a complex system that performs information processing functions through optoelectronic devices, including optical communication systems, optical switching systems, all-optical signal processing systems, optical computers and microwave photonic systems. Traditional optoelectronic information systems are mainly implemented through free space optical paths or all-fiber optical paths. The light field carrying information is transmitted in free space or in optical fibers, and the light field is controlled by controlling optoelectronic devices through external circuits. However, free space optical paths and all-fiber optical paths face many problems such as large system volume, poor stability, difficulty in coordinated control, and slow upgrade rate, making it difficult to carry out large-scale applications outside the laboratory environment. More importantly, the loosely coupled integration of various optoelectronic devices has seriously increased the difficulty of designing control circuits for traditional optoelectronic information systems. On the other hand, thanks to the rapid development of chip integrated optoelectronic device preparation technology, chip integrated optoelectronic devices including optical modulators, optical filters, directional couplers, and wavelength division multiplexers have performance indicators that are not inferior to traditional discrete optoelectronic devices. Single-chip optoelectronic information systems have the advantages of small size, low power consumption, strong stability, and batch preparation.

[0003] Optical filters are widely used in optoelectronic information systems, and typical applications include wavelength division multiplexing optical communications, optical Fourier transform, microwave photon signal shaping, etc. The main performance indicators for measuring optical filters include central wavelength, full width at half maximum, extinction ratio, transmission spectrum shape, etc. The adjustable ability of each parameter will directly affect the flexible control ability of typical applications. Summary of the invention

[0004] Based on the problems of the prior art, the technical problem to be solved by the present invention is how to prepare and integrate multiple discrete microring filters on a single chip, wherein the free spectral range of each filter is different and all are ITU standard frequency intervals. Each filter can independently tune the central wavelength by controlling the voltage, and utilize the path selection optical path to make the signal light field transmitted along different paths and pass through different filters. By changing the control voltage distribution, the filtering function with switchable free spectral range can be realized.

[0005] In view of the defects existing in the prior art, the purpose of the present invention is to provide a multifunctional microcavity waveguide structure based on a coating structure, which fully utilizes the performance advantages of two-dimensional layered material coatings such as transition metal sulfides in improving modulation rate and enhancing nonlinear response, fully expands the function of a single microcavity, greatly improves the functional reuse level of a single optoelectronic device, and provides device support for chip-integrated software-defined optical systems and microwave photonic systems.

[0006] In order to achieve the above effect, the present invention provides a method for realizing switchable filtering in a free spectral range based on a path selection optical path, wherein multiple discrete filters are prepared and integrated on a single chip, each filter having a different free spectral range and all having ITU standard frequency intervals, and the independent tuning of the center wavelength of each filter is realized by an external bias voltage;

[0007] The signal light field is switched to the optical path where different filters are located as needed through an external bias voltage, and the signal light fields passing through different filters are exported from a unified port to realize a filter function with switchable free spectral range.

[0008] Preferably, a plurality of parallel filters are prepared on a single chip, and the transmission path of the signal light field is adjusted by controlling the path selection optical path through the chip integrated logic circuit and passing it through different filters, thereby realizing programmable filtering with flexible switchable free spectrum range of ITU standard frequency interval.

[0009] Preferably, the above method specifically includes:

[0010] Step 1: Prepare a discrete filter waveguide structure. Each filter is connected by a path selection optical path and a transmission waveguide. A grating coupler is prepared to import or export the signal light field into or out of the chip. The free spectrum range of each filter is different and must be an integer multiple of the ITU standard frequency interval.

[0011] Step 2: Prepare each filter control electrode, and connect the control electrode to an external circuit using an integrated wire;

[0012] Step 3: Load the digital logic control voltage to the path selection optical path and the phase shifter of the micro-ring cavity through an external circuit, and realize the flexible switching of the signal light field transmission path by controlling the path selection optical path, and finally feedback as a filtered output spectrum with flexible and adjustable resonant wavelength and free spectral range.

[0013] Preferably, the above-mentioned chip integrated filter is prepared by a standard chip integrated optical path process, has a certain degree of freedom in structural design, can efficiently and losslessly transmit the light field, has a certain bandpass or bandstop capability in the frequency domain, and achieves transmission spectrum tuning by changing the waveguide refractive index.

[0014] Preferably, the above-mentioned chip integrated logic circuit is prepared by chip integrated circuit standard process, has a certain degree of freedom in structural design, changes the refractive index of the transmission waveguide in the filter structure to achieve filter center wavelength tuning, is connected to an external logic circuit through a control electrode-integrated wire-pin electrode, and receives bias voltages of different intensities.

[0015] Preferably, the above-mentioned free spectrum range switchable filter can flexibly change the resonant wavelength and free spectrum range parameters through the bias voltage distribution on multiple control electrodes, and realize the conversion from mathematical logic (input) to filtering parameters (output) in the order of logical definition, bias voltage distribution, optical path, and different free spectrum range filtering spectra.

[0016] Preferably, the above-mentioned programmable input quantity is binary logic, discrete logic or continuous variable, and is not limited to programming language, interface definition and compilation rules.

[0017] The present invention provides a system for realizing switchable filtering in a free spectral range based on a path selection optical path, comprising a micro-ring cavity structure, in which a grating coupler, a plurality of cascaded Mach-Zehnder interferometers, a plurality of phase shifters and a plurality of micro-rings are arranged;

[0018] The signal light field is input into the path selection optical path composed of cascaded Mach-Zehnder interferometers through a grating coupler. By applying bias voltage to three phase shifters through an external circuit, the signal light field can be considered to be selected to pass through four different optical paths. Four microrings with different radii are located on different optical paths. By controlling the radius and cross-sectional structure of the microrings, the microring transmission spectrum can have a free spectral range that is an integer multiple of the ITU standard frequency interval, and the resonant wavelength of each microring cavity can be tuned by a phase shifter. The signal light field passing through each microring is filtered to produce spectral recombination or generate a nonlinear optical frequency comb, and is output from the grating coupler of a specific port through the path selection optical path composed of cascaded Mach-Zehnder interferometers.

[0019] Preferably, the above system controls different external electrodes to make the signal light field pass through different optical paths, thereby achieving switchable filtering in a free spectral range and wavelength tuning of each filter.

[0020] A computer-readable storage medium stores a computer program, which implements the above method when executed by a processor.

[0021] A computer program product comprises a computer program / instruction, which implements the steps of the above method when executed by a processor.

[0022] Compared with the existing technology, the present invention solves the problem that traditional filters can only tune the central wavelength but cannot change the transmission spectrum, improves the flexibility of optoelectronic information systems in frequency domain processing, and provides an important solution for the research and development of logic-programmable and software-definable optoelectronic information systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following briefly introduces the drawings required for use in the embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic diagram of a multifunctional microcavity waveguide structure based on a coating structure of the present invention is shown;

[0025] Figure 2 A schematic flow chart of an embodiment of a method for realizing switchable filtering in a free spectral range based on path selection optical path of the present invention is shown;

[0026] Figure 3 A schematic flow chart of another embodiment of the method for realizing free spectral range switchable filtering based on path selection optical path of the present invention is shown. DETAILED DESCRIPTION

[0027] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and Examples. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention.

[0028] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0029] The present invention provides an embodiment of a method for realizing switchable filtering in a free spectral range based on a path selection optical path, wherein a plurality of discrete filters are integrated on a single chip, each filter having a different free spectral range and all having an ITU standard frequency interval, and independent tuning of the center wavelength of each filter is realized by an external bias voltage;

[0030] The signal light field is switched to the optical path where different filters are located as needed through an external bias voltage, and the signal light fields passing through different filters are exported from a unified port to realize a filter function with switchable free spectral range.

[0031] In some embodiments, multiple parallel filters are prepared on a single chip, and the path selection optical path is controlled by the chip integrated logic circuit to adjust the transmission path of the signal light field and pass it through different filters, thereby realizing programmable filtering with flexible switching of the free spectrum range of the ITU standard frequency interval.

[0032] The present invention provides an embodiment of a method for realizing free spectral range switchable filtering based on path selection optical path, comprising:

[0033] Step 1: Prepare a discrete filter waveguide structure. Each filter is connected by a path selection optical path and a transmission waveguide. A grating coupler is prepared to import or export the signal light field into or out of the chip. The free spectrum range of each filter is different and must be an integer multiple of the ITU standard frequency interval.

[0034] Step 2: Prepare each filter control electrode, and connect the control electrode to an external circuit using an integrated wire;

[0035] Step 3: Load the digital logic control voltage to the path selection optical path and the phase shifter of the micro-ring cavity through an external circuit, and realize the flexible switching of the signal light field transmission path by controlling the path selection optical path, and finally feedback as a filtered output spectrum with flexible and adjustable resonant wavelength and free spectral range.

[0036] In some embodiments, the chip integrated filter is prepared by a standard chip integrated optical path process, has a certain degree of freedom in structural design, can efficiently and losslessly transmit the light field, has a certain bandpass or bandstop capability in the frequency domain, and achieves transmission spectrum tuning by changing the waveguide refractive index.

[0037] In some embodiments, the chip integrated logic circuit is prepared through standard chip integrated circuit technology, has a certain degree of structural design freedom, changes the refractive index of the transmission waveguide in the filter structure to achieve filter center wavelength tuning, is connected to an external logic circuit through a control electrode-integrated wire-pin electrode, and receives bias voltages of different intensities.

[0038] In some embodiments, the free spectrum range switchable filter can flexibly change the resonant wavelength and free spectrum range parameters through the bias voltage distribution on multiple control electrodes, and realize the conversion from mathematical logic (input quantity) to filtering parameters (output quantity) in the order of logical definition, bias voltage distribution, optical path, and different free spectrum range filtering spectra.

[0039] In some embodiments, the programmable input quantity is binary logic, discrete logic or continuous variable, and is not limited by programming language, interface definition and compilation rules.

[0040] The present invention provides a system for realizing a method of switchable filtering in a free spectral range based on a path selection optical path, comprising a micro-ring cavity structure, in which a grating coupler, a plurality of cascaded Mach-Zehnder interferometers, a plurality of phase shifters and a plurality of micro-rings are arranged;

[0041] The signal light field is input into the path selection optical path composed of cascaded Mach-Zehnder interferometers through a grating coupler. By applying bias voltage to three phase shifters through an external circuit, the signal light field can be considered to be selected to pass through four different optical paths. Four microrings with different radii are located on different optical paths. By controlling the radius and cross-sectional structure of the microrings, the microring transmission spectrum can have a free spectral range that is an integer multiple of the ITU standard frequency interval, and the resonant wavelength of each microring cavity can be tuned by a phase shifter. The signal light field passing through each microring is filtered to produce spectral recombination or generate a nonlinear optical frequency comb, and is output from the grating coupler of a specific port through the path selection optical path composed of cascaded Mach-Zehnder interferometers.

[0042] In some embodiments, the system controls different external electrodes to make the signal light field pass through different optical paths, thereby achieving free spectral range switchable filtering and wavelength tuning of each filter.

[0043] like Figure 1As shown, this embodiment shows a free spectrum range switchable filter structure based on a path selection optical path: the signal light field is input into the path selection optical path composed of cascaded Mach-Zehnder interferometers through a grating coupler, and a bias voltage is applied to three phase shifters through an external circuit, which can be considered to select the signal light field to pass through four different optical paths; four microrings with different radii are located on different optical paths, and by controlling the radius and cross-sectional structure of the microrings, the microring transmission spectrum can have a free spectrum range that is an integer multiple of the ITU standard frequency interval, and the resonance wavelength of each microring cavity can be tuned by the phase shifter; the signal light field passing through each microring is filtered, resulting in spectral recombination or generating a nonlinear optical frequency comb, and is output from the grating coupler of a specific port through the path selection optical path composed of cascaded Mach-Zehnder interferometers; in the above process, the precise control of the 1st to 3rd and 8th to 10th external electrodes can make the signal light field pass through different optical paths, that is, realize free spectrum range switchable filtering, and the 4th to 7th external electrodes realize the wavelength tuning of each filter.

[0044] like Figure 2 As shown, the present invention provides an embodiment of a method for realizing free spectral range switchable filtering based on path selection optical path, comprising:

[0045] S101, design, preparation and independent control of filters, preparation and integration of multiple discrete filters on a single chip, each filter has a different free spectral range and all are ITU standard frequency intervals, and the independent tuning of the center wavelength of each filter is achieved through external bias voltage;

[0046] S102. Design, preparation and independent control of the path selection optical path, i.e., cascaded Mach-Zehnder interferometer, switching the signal light field to the optical path where different filters are located as needed through an external bias voltage, and exporting the signal light field passing through different filters from a unified port, to realize the filtering function with switchable free spectral range.

[0047] like Figure 3 As shown, the present invention provides an embodiment of a method for realizing free spectral range switchable filtering based on path selection optical path, comprising:

[0048] S201. Prepare discrete filter waveguide structures by using a standard chip integrated optical path preparation process. Each filter is connected by a path selection optical path and a transmission waveguide. A grating coupler is prepared to import or export a signal light field into or out of the chip. The free spectral range of each filter is different and must be an integer multiple of the ITU standard frequency interval.

[0049] S202, preparing each filter control electrode by using a standard chip integrated circuit process, and connecting the control electrode to an external circuit by using an integrated wire;

[0050] S203, loading the digital logic control voltage onto the path selection optical path and the phase shifter of the micro-ring cavity through an external circuit, realizing flexible switching of the signal light field transmission path by controlling the path selection optical path, and finally feeding back into a filter output spectrum with a flexibly adjustable resonant wavelength and free spectral range.

[0051] The present invention provides an embodiment of a method for realizing switchable filtering in a free spectral range based on a path selection optical path. A plurality of parallel filters are prepared on a single chip. The path selection optical path is controlled by a chip integrated logic circuit to adjust the transmission path of a signal light field and pass it through different filters, thereby realizing programmable filtering with flexible switchable free spectral range of ITU standard frequency interval.

[0052] In some embodiments, the chip integrated filter can be prepared by chip integrated optical circuit standard process, has a certain degree of freedom in structural design, can transmit light fields efficiently and losslessly, has a certain bandpass or bandstop capability in the frequency domain, can achieve transmission spectrum tuning by changing the waveguide refractive index, and the basic tuning principles include but are not limited to thermo-optical effect, electro-optical effect, photoelectric effect, etc.

[0053] In some specific embodiments, including but not limited to arrayed waveguide gratings, Mach-Zehnder interferometers, micro-ring cavities, whispering gallery micro-disc cavities, photonic crystal slow-light micro-cavities, Fabry-Perot cavities, Bragg gratings, etc., the cascaded filters may have the same structure or different structures.

[0054] In some specific embodiments, the material platform used includes but is not limited to silicon on insulator, hydrogenated amorphous silicon, silicon nitride, silicon carbide, chalcogenide glass, Group III-V aluminum gallium arsenide, Group III-V indium phosphide, etc., and both a single material integration method and a multi-material hybrid integration method can be adopted.

[0055] In some specific embodiments, the chip integrated logic circuit can be prepared through chip integrated circuit standard process, has a certain degree of freedom in structural design, can change the refractive index of the transmission waveguide in the filter structure to achieve filter center wavelength tuning, can be connected to an external logic circuit through the control electrode-integrated wire-pin electrode, can receive bias voltages of different intensities, and does not limit the structural dimensions and wiring parameters of the control band, integrated wire, and pin electrode, and does not limit the interface definition principles and logic compilation methods.

[0056] In some specific embodiments, the free spectrum range switchable filter can flexibly change parameters such as the resonant wavelength and the free spectrum range through the bias voltage distribution on multiple control electrodes, and can realize the conversion from mathematical logic (input) to filtering parameters (output) in the order of logic definition → bias voltage distribution → optical path → different free spectrum range filtering spectra.

[0057] In some specific embodiments, the programmable input quantity can be binary logic, discrete logic or continuous variable, and there is no limitation on programming language, interface definition and compilation rules. There is no limitation on the type, characteristics and quantity of normalized filter spectra in the output quantity set, and there is no limitation on the specific structure and implementation method of the programmable filtering system.

[0058] The present invention also provides an embodiment of a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the above method is implemented.

[0059] The present invention also provides an embodiment of a computer program, which implements the above method when executed by a processor.

[0060] Compared with the prior art, the present invention has the following advantages:

[0061] First, the traditional discrete filter has only one degree of tuning freedom, the central wavelength, which is difficult to meet the complex frequency domain signal processing requirements of the optoelectronic information system. The technical solution proposed in the present invention expands the tuning freedom to the free spectrum range, improving the frequency domain signal processing capability of the optoelectronic information system.

[0062] Secondly, the present invention proposes the concept of logical programmable filtering, which establishes a compiled correspondence between digital logic and the free spectral range of the filtering spectrum, laying the foundation for precise, standardized and diversified optical fiber communication signal processing.

[0063] In addition, the present invention can provide a solution for standardized optoelectronic device design and software-defined microwave photonic system development.

[0064] For the convenience of description, the above device is described in various units according to their functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0065] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0066] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0067] The present application may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0068] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0069] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0070] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0071] The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0072] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0073] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0074] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0075] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for realizing free spectral range switchable filtering based on path selection optical path, characterized in that: Multiple discrete micro-ring filters are integrated on a single chip. The free spectrum range of each micro-ring filter is different and all have ITU standard frequency intervals. The center wavelength of each micro-ring filter can be independently tuned through an external circuit. The signal light field is switched to the optical paths where different micro-ring filters are located as needed through an external circuit, and the signal light fields passing through different micro-ring filters are exported from a unified port to realize the filtering function with switchable free spectral range. The system of the method for realizing switchable free spectral range filtering based on the path selection optical path is provided with a grating coupler, a plurality of cascaded Mach-Zehnder interferometers, a plurality of phase shifters and a plurality of micro-rings; the signal light field is loaded onto the path selection optical path and the phase shifter of the micro-ring through the external circuit, and the signal light field is input into the path selection optical path composed of the cascaded Mach-Zehnder interferometer through the grating coupler, and a bias voltage is applied to the three phase shifters of the path selection optical path through the external circuit, that is, the signal light field is selected to pass through four different optical paths; four micro-rings with different radii are located on different optical paths, and by controlling the radius and cross-sectional structure of the micro-ring, the micro-ring transmission spectrum can have an integer multiple of ITU The free spectrum range of standard frequency interval, the resonant wavelength of each microring can be tuned by a phase shifter; the signal light field passing through each microring is filtered to produce spectral recombination or generate a nonlinear optical frequency comb, and the path selection light path composed of a cascaded Mach-Zehnder interferometer is output from the grating coupler of a specific port.

2. The method for realizing free spectral range switchable filtering based on path selection optical path according to claim 1, characterized in that: The method prepares multiple parallel filters on a single chip, and uses the chip integrated logic circuit to control the path selection optical path to adjust the transmission path of the signal light field and pass it through different filters, thereby realizing programmable filtering with flexible switching of the free spectrum range of the ITU standard frequency interval.

3. The method for realizing free spectral range switchable filtering based on path selection optical path according to claim 1 or 2, characterized in that: The method specifically comprises: Step 1: Prepare a discrete filter waveguide structure. Each filter is connected by a path selection optical path and a transmission waveguide. A grating coupler is prepared to import or export the signal light field into or out of the chip. The free spectrum range of each filter is different and must be an integer multiple of the ITU standard frequency interval. Step 2: Prepare each filter control electrode, and connect the control electrode to an external circuit using an integrated wire; Step 3: Load the digital logic control voltage to the path selection optical path and the phase shifter of the micro-ring cavity through an external circuit, and realize the flexible switching of the signal light field transmission path by controlling the path selection optical path, and finally feedback as a filtered output spectrum with flexible and adjustable resonant wavelength and free spectral range.

4. The method for realizing free spectral range switchable filtering based on path selection optical path according to claim 1 or 2, characterized in that: The free spectrum range switchable filter can flexibly change the resonant wavelength and free spectrum range parameters through the bias voltage distribution on multiple control electrodes, and realize the conversion from mathematical logic input to filter parameter output in the order of logic definition, bias voltage distribution, optical path, and different free spectrum range filter spectra.

5. A computer-readable storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the method according to any one of claims 1 to 4.

Images