Wavelength converter, optical frequency comb generation device and wavelength converter preparation method

Abstract

The invention relates to a wavelength converter, an optical frequency comb generation device and a wavelength converter preparation method. The wavelength converter comprises a gain optical fiber and a nonlinear wavelength conversion material, the nonlinear wavelength conversion material is attached to the polishing plane of the gain fiber; and under the condition that the optical frequency comb with the initial central wavelength enters the gain fiber, generating an optical frequency comb with a preset central wavelength through the nonlinear wavelength conversion material. By introducing a nonlinear wavelength conversion material, the nonlinear wavelength conversion material is attached to a polished plane of a gain optical fiber, the second-order nonlinear effect of the gain optical fiber is remarkably enhanced, when an optical frequency comb with an initial central wavelength enters the gain optical fiber, the optical frequency comb with the initial central wavelength interacts with the nonlinear wavelength conversion material, and the optical frequency comb with the initial central wavelength interacts with the nonlinear wavelength conversion material. Through secondary harmonic generation, an optical frequency comb with a preset central wavelength is output, and efficient optical frequency comb generation near a 765nm wave band is realized.

Description

Technical Field

[0001] The present application relates to the field of optical technology, and in particular to a wavelength converter, an optical frequency comb generating device, and a method for preparing the wavelength converter. Background Art

[0002] As a high-precision and high-stability light source, optical frequency comb has broad application prospects in optical communications, spectral analysis, optical frequency standards and other fields.

[0003] In related technologies, mode-locked lasers lock the phases of multiple longitudinal modes so that they oscillate simultaneously, thereby generating a series of equally spaced frequency components, which form equally spaced spectral lines in the frequency domain, namely, optical frequency combs. However, there are still many challenges in the generation of optical frequency combs in the visible light band, especially near the 765nm band.

[0004] Therefore, how to achieve efficient optical frequency comb generation near the 765nm band is an urgent problem to be solved. Summary of the invention

[0005] Based on this, it is necessary to provide a wavelength converter, an optical frequency comb generating device and a wavelength converter preparation method to address the above-mentioned technical problems, which can achieve efficient optical frequency comb generation near the 765nm band.

[0006] In a first aspect, an embodiment of the present application provides a wavelength converter, the wavelength converter comprising a gain optical fiber and a nonlinear wavelength conversion material; the nonlinear wavelength conversion material is attached to a polished surface of the gain optical fiber;

[0007] When an optical frequency comb with an initial central wavelength is incident on a gain fiber, an optical frequency comb with a preset central wavelength is generated through a nonlinear wavelength conversion material.

[0008] In one embodiment, the polished surface of the gain optical fiber is a polished surface of a D-shaped optical fiber obtained by polishing the cladding of the gain optical fiber.

[0009] In one embodiment, the gain fiber is a single mode fiber.

[0010] In one embodiment, the nonlinear wavelength conversion material is a single layer of tungsten diselenide.

[0011] In one embodiment, the initial central wavelength is in the 1530 nm band; the preset central wavelength is in the 765 nm band.

[0012] In one embodiment, the gain fiber has a core refractive index of 1.4504, a core diameter of 9 um, and a cladding refractive index of 1.4437.

[0013] In a second aspect, an embodiment of the present application provides an optical frequency comb generating device in the visible light band, the device comprising a mode-locked laser and a wavelength converter as described in any one of the first aspects above.

[0014] In one embodiment, the central wavelength of the optical frequency comb generated by the mode-locked laser is in the 1530 nm band; the visible light band is in the 765 nm band.

[0015] In a third aspect, an embodiment of the present application further provides a method for preparing a wavelength converter, the method comprising:

[0016] Polishing one side cladding of the gain optical fiber to obtain a gain optical fiber including a polishing plane; the polishing plane is at a preset position away from the core of the gain optical fiber;

[0017] The prepared nonlinear wavelength conversion material is transferred to a polished surface to obtain a wavelength converter.

[0018] In one embodiment, the sheet of nonlinear wavelength conversion material is on an adhesive tape; transferring the prepared nonlinear wavelength conversion material to a polished surface comprises:

[0019] The tape carrying the thin sheet is adhered to the polydimethylsiloxane (PDMS) on the glass slide to obtain a nanosheet with a thickness of a single atomic layer;

[0020] Assemble the glass slide carrying the nanosheet and PDMS on a three-dimensional translation stage; PDMS is located below the nanosheet;

[0021] The three-dimensional translation stage is moved to the sample stage where the gain optical fiber is fixed, and the temperature of the translation stage is increased until the PDMS loses its viscosity, and then the nonlinear wavelength conversion material is transferred to the polished surface of the gain optical fiber.

[0022] In a fourth aspect, an embodiment of the present application further provides a wavelength converter manufacturing device, comprising:

[0023] An optical fiber polishing module is used to polish a cladding layer on one side of the gain optical fiber to obtain a gain optical fiber including a polishing plane; the polishing plane is at a preset position away from the core of the gain optical fiber;

[0024] The material transfer module is used to transfer the prepared nonlinear wavelength conversion material to the polishing plane to obtain a wavelength converter.

[0025] In a fifth aspect, an embodiment of the present application further provides a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps in any one of the embodiments of the third aspect are implemented.

[0026] In a sixth aspect, the embodiments of the present application further provide a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the steps in any one of the embodiments of the third aspect are implemented.

[0027] In a seventh aspect, the embodiments of the present application further provide a computer program product, which includes a computer program, and when the computer program is executed by a processor, the steps in any one of the embodiments in the third aspect are implemented.

[0028] The wavelength converter, optical frequency comb generating device and wavelength converter preparation method provided by the embodiment of the present application, the wavelength converter includes a gain fiber, a nonlinear wavelength conversion material; the nonlinear wavelength conversion material is attached to the polished surface of the gain fiber; when the optical frequency comb of the initial center wavelength is incident on the gain fiber, the optical frequency comb of the preset center wavelength is generated by the nonlinear wavelength conversion material. In the wavelength converter, by introducing the nonlinear wavelength conversion material and attaching the nonlinear wavelength conversion material to the polished surface of the gain fiber, the second-order nonlinear effect of the gain fiber is significantly enhanced. When the optical frequency comb of the initial center wavelength is incident on the gain fiber, the optical frequency comb of the initial center wavelength interacts with the nonlinear wavelength conversion material, and the optical frequency comb of the preset center wavelength is output through second harmonic generation, thereby realizing efficient optical frequency comb generation near the 765nm band. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] FIG1 is a schematic diagram of a wavelength converter according to an embodiment;

[0031] FIG2 is a schematic diagram showing how the refractive index varies with wavelength in one embodiment;

[0032] FIG3 is a schematic flow chart of a method for preparing a wavelength converter in one embodiment;

[0033] FIG. 4 is a schematic diagram of the structure of a wavelength converter manufacturing device in one embodiment. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0036] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0037] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0038] As a high-precision, high-stability light source, optical frequency comb has broad application prospects in the fields of optical communication, spectral analysis, optical frequency standards, etc. The frequency comb in the visible light band has important application scenarios in the fields of biochemical analysis, precise optical clocks, and quantum communications. However, there are still many challenges in the current optical frequency comb generation technology in the visible light band, especially in this band, the waveguide materials (silicon dioxide, silicon nitride, calcium fluoride, etc.) have strong normal dispersion and scattering. In addition, the traditional gain wavelength, especially from doped particles, does not cover the visible light band. Therefore, it is difficult for existing technologies to achieve efficient optical frequency comb generation near the 765nm band.

[0039] Based on this, the present application provides a wavelength converter, which includes a gain fiber and a nonlinear wavelength conversion material; the nonlinear wavelength conversion material is attached to the polished surface of the gain fiber; when the optical frequency comb of the initial center wavelength is incident on the gain fiber, the optical frequency comb of the preset center wavelength is generated by the nonlinear wavelength conversion material. In the wavelength converter, by introducing the nonlinear wavelength conversion material and attaching the nonlinear wavelength conversion material to the polished surface of the gain fiber, the second-order nonlinear effect of the gain fiber is significantly enhanced. When the optical frequency comb of the initial center wavelength is incident on the gain fiber, the optical frequency comb of the initial center wavelength interacts with the nonlinear wavelength conversion material, and through second harmonic generation, an optical frequency comb of the preset center wavelength is output, thereby realizing efficient optical frequency comb generation near the 765nm band.

[0040] In an exemplary embodiment, as shown in FIG1 , a wavelength converter 10 is provided, the wavelength converter 10 comprising a gain fiber 11 and a nonlinear wavelength conversion material 12; the nonlinear wavelength conversion material 12 is attached to a polished surface of the gain fiber 11;

[0041] When the optical frequency comb with the initial central wavelength is incident on the gain fiber 11 , an optical frequency comb with a preset central wavelength is generated through the nonlinear wavelength conversion material 12 .

[0042] The nonlinear wavelength conversion material 12 refers to a material that can produce a nonlinear optical effect, thereby achieving wavelength conversion. In the embodiment of the present application, the nonlinear wavelength conversion material 12 is a single layer of tungsten diselenide ( ). Single layer It is a nonlinear optical material with an asymmetric structure in a single atomic layer and has a second-order nonlinear effect. The crystal can significantly enhance the second-order nonlinear conversion efficiency of the optical fiber through the interaction of the evanescent field with the light in the optical fiber, thus making the 1530nm optical frequency comb laser and The interaction generates a 765nm wavelength optical frequency comb laser through second harmonic generation.

[0043] The nonlinear wavelength conversion material 12 is attached to the polished surface of the gain fiber 11. Among them, the polished surface of the gain fiber 11 is the polished surface of the D-shaped fiber obtained by polishing the cladding of the gain fiber. It should be noted that the entire cladding on one side of the gain fiber can be polished to obtain the polished surface, and the cladding in a preset range in the gain fiber can also be polished to obtain the polished surface, for example, the cladding on one side of the gain fiber in the middle position is polished. Polishing can be performed according to actual needs and scenarios, and the embodiments of the present application are not limited to this. The gain fiber 11 is a single-mode fiber. When an optical frequency comb with an initial central wavelength is incident on the gain fiber, an optical frequency comb with a preset central wavelength is generated by the nonlinear wavelength conversion material. Among them, the initial central wavelength is the 1530nm band; the preset central wavelength is the 765nm band.

[0044] Silicon-based materials have traditionally been limited to third-order nonlinear interactions because they are inherently centrosymmetric in crystals or amorphous forms. Second-order nonlinear optical processes require breaking the symmetry of the material. The second harmonic generation effect converts the frequency comb in the 1530nm band into an optical frequency comb in the 765nm band, circumventing the traditional challenges of realizing frequency combs in the visible light range.

[0045] Due to the different refractive indices of the two light waves in the waveguide, there is a phase mismatch between the newly generated 765nm frequency comb and the 1530nm frequency comb. The interaction distance increases and accumulates, resulting in a significant reduction in the efficiency of the nonlinear process, or even completely preventing the conversion and propagation of light waves. By designing the single-mode fiber waveguide material and structural dimensions, the core refractive index is 1.4504, the core diameter is 9um, and the cladding refractive index is 1.4437. In this case, the refractive index of the 1530nm LP01 (fundamental mode) longitudinal mode and the 765nm LP11 (higher-order mode) longitudinal mode are very close. Therefore, when the 1530nm LP01 mode optical frequency comb laser is converted into 765nm light through the second harmonic SHG process and enters the LP11 mode for propagation, the two light waves can propagate at the same speed in the waveguide, maintaining phase matching, thereby solving the phase mismatch problem that is prevalent in similar structures.

[0046] In the wavelength converter finally realized in the embodiment of the present application, the diameter of the single-mode optical fiber is 125 microns, the core diameter is 9 microns, and the optical frequency comb with a central wavelength of 1530 is incident on the gain optical fiber, and the evanescent field and the gain optical fiber are connected on the polishing plane. The interaction generates an optical frequency comb with a central wavelength of 765nm through the SHG process. As shown in Figure 2, the structure has the same refractive index at 765nm and 1530nm, thus achieving stable optical frequency comb output. As a two-dimensional material with excellent nonlinear optical properties, phase can introduce strong second-order nonlinear effects into optical fibers that originally have almost no second-order nonlinearity, thereby significantly improving the generation efficiency of optical frequency combs.

[0047] The wavelength converter provided in the embodiment of the present application includes a gain fiber and a nonlinear wavelength conversion material; the nonlinear wavelength conversion material is attached to the polished surface of the gain fiber; when the optical frequency comb of the initial center wavelength is incident on the gain fiber, the optical frequency comb of the preset center wavelength is generated by the nonlinear wavelength conversion material. In the wavelength converter, by introducing the nonlinear wavelength conversion material and attaching the nonlinear wavelength conversion material to the polished surface of the gain fiber, the second-order nonlinear effect of the gain fiber is significantly enhanced. When the optical frequency comb of the initial center wavelength is incident on the gain fiber, the optical frequency comb of the initial center wavelength interacts with the nonlinear wavelength conversion material, and through the second harmonic generation, the optical frequency comb of the preset center wavelength is output, thereby realizing the efficient generation of the optical frequency comb near the 765nm band.

[0048] In an exemplary embodiment, the present application also provides an optical frequency comb generator in the visible light band, and the optical frequency comb generator in the visible light band includes a mode-locked laser and a wavelength converter in any of the aforementioned embodiments.

[0049] Among them, the central wavelength of the optical frequency comb generated by the mode-locked laser is in the 1530nm band; the visible light band is in the 765nm band.

[0050] The wavelength converter includes a gain fiber and a nonlinear wavelength conversion material; the nonlinear wavelength conversion material is attached to the polished surface of the gain fiber; the optical frequency comb in the 1530nm band generated by the mode-locked laser is incident on the gain fiber, and outputs an optical frequency comb in the 765nm band through interaction with the nonlinear wavelength conversion material.

[0051] In this embodiment, the optical frequency comb generating device in the visible light band includes a mode-locked laser and a wavelength converter, and the wavelength converter includes a gain fiber and a nonlinear wavelength conversion material; the nonlinear wavelength conversion material is attached to the polished surface of the gain fiber, and the optical frequency comb in the 1530nm band generated by the mode-locked laser is incident on the gain fiber, and the optical frequency comb with a preset central wavelength is generated by the nonlinear wavelength conversion material. In the device, by introducing the nonlinear wavelength conversion material and attaching the nonlinear wavelength conversion material to the polished surface of the gain fiber, the second-order nonlinear effect of the gain fiber is significantly enhanced. When the optical frequency comb in the 1530nm band in the mode-locked laser is incident on the gain fiber, the optical frequency comb in the 1530nm band interacts with the nonlinear wavelength conversion material, and the optical frequency comb in the 765nm band is output through second harmonic generation, thereby realizing efficient optical frequency comb generation near the 765nm band.

[0052] In an exemplary embodiment, as shown in FIG3 , the present application also provides a method for preparing a wavelength converter, the method comprising:

[0053] S101, polishing one side cladding of the gain optical fiber to obtain a gain optical fiber including a polishing plane; the polishing plane is at a preset position away from the core of the gain optical fiber.

[0054] Exemplarily, the gain fiber is fixed on a fixture, and the coating layer of the gain fiber is removed; the gain fiber is roughly ground using a grinding wheel with a preset mesh number to obtain a roughly ground gain fiber; the grinding wheel with a different mesh number is replaced to finely grind and polish the roughly ground gain fiber to obtain a gain fiber including a polishing area. The rough grinding process includes rough grinding the cladding of the gain fiber according to the grinding wheel while passing light through the gain fiber; the grinding wheel is fixed on a three-dimensional stepping stage, and the three-dimensional stepping stage controls the depth of the grinding wheel along the vertical axis and controls the polishing length along the axial direction of the gain fiber; when it is determined that the rough grinding reaches the core position of the gain fiber based on the transmission loss waveform monitored by the power meter, the rough grinding is stopped to obtain the roughly ground gain fiber.

[0055] In the embodiment of the present application, a diamond grinding wheel with replaceable particle size is used to polish the side of the gain fiber. In order to improve the surface smoothness of the polishing, the processing depth and smoothness are precisely controlled by changing the mesh number of the grinding wheel (the number of particles per unit area). The polishing process is designed to be rough grinding, fine grinding, and polishing. The diameter of the grinding wheel is set to 12.5 cm, and the optional mesh numbers are 1000, 3000, 5000, and 12000. First, a low-mesh grinding wheel is used to quickly rough grind to the core position, and then a high-mesh grinding wheel is used to finely grind to improve the surface smoothness. Finally, the mesh number of 12000 is replaced for polishing to reduce the additional loss of light caused by surface scattering. In order to control the accuracy of polishing, a polishing control system composed of a light source, a power meter, a test bench, and a three-dimensional stepping table is used to monitor the polishing depth and length. The specific process includes: removing part of the coating layer of the single-mode optical fiber, fixing the optical fiber, the 980nm light source, and the power meter on the test bench fixture, passing light to the optical fiber, and using the power meter to monitor the transmission loss of the optical fiber. Choose a 1000 mesh grinding wheel for rough grinding, fix the grinding wheel on a three-dimensional stepping table, use the stepping platform to control the grinding wheel depth along the Z direction, and control the polishing length along the fiber axis (Y direction). When the power meter detects a sudden drop in optical power, stop the grinding wheel, change the grinding wheel mesh, and start fine grinding and polishing. This is because when grinding to the fiber core position, the optical signal in the fiber core is transmitted to the outside world, and the transmission loss will be greatly reduced. Therefore, you only need to observe the transmission loss. When the stable transmission loss suddenly changes, stop the grinding wheel to control the appropriate rough grinding depth. The polishing plane is about 1 micron away from the fiber core to ensure Effective interaction between the film and the fiber core.

[0056] S102, transferring the prepared nonlinear wavelength conversion material to a polished surface to obtain a wavelength converter.

[0057] In the embodiment of the present application, the nonlinear wavelength conversion material is a single layer The monolayer was prepared by mechanical exfoliation Compared with the preparation method of chemical vapor deposition, mechanical exfoliation can obtain higher crystal quality. First, prepare high-quality Single crystal, polydimethylsiloxane (PDMS) was selected as the substrate. Cut a small area of ​​the crystal suitable for peeling and stick the tape to the cut area. The surface of the crystal is peeled off layer by layer by slowly stretching the tape. The peeling thickness will gradually decrease as the tape is stretched, and a single layer or a few layers can be obtained in the end. Film. The first layer is placed in contact with the substrate and the material is transferred to the substrate surface by gentle pressure or heating. Temperature and pressure must be controlled to avoid cracking or contamination of the material. Finally, the tape is carefully peeled from the substrate, leaving a single layer. This process requires great delicacy to ensure that the material is not torn or damaged.

[0058] In the preparation After that, The film is transferred to the polished surface. Exemplarily, a tape carrying a thin sheet is adhered to polydimethylsiloxane (PDMS) on a glass slide to obtain a nanosheet with a single atomic layer thickness; the glass slide carrying the nanosheet and PDMS is assembled on a three-dimensional translation stage; the PDMS is located below the nanosheet; the three-dimensional translation stage is moved to the sample stage where the gain fiber is fixed, and the temperature of the translation stage is increased until the PDMS loses its viscosity, and the nonlinear wavelength conversion material is transferred to the polished surface of the gain fiber.

[0059] For example, a dry transfer process is used to ensure effective coupling with the fiber core. The size of the film is about 20um*50um. Use an XYZ stage and a sample stage to assist in the transfer. The specific process is to assemble the glass slide carrying the PDMS / PC film on the XYZ stage, with the PDMS bottom facing down, adjust the XYZ stage, fix the optical fiber on the sample stage, heat the XYZ stage to 70℃, and the PDMS loses its viscosity. The nanosheets are transferred to the optical fiber.

[0060] The wavelength converter preparation method provided in the embodiment of the present application comprises the following steps: polishing the cladding of one side of the gain fiber to obtain a gain fiber including a polishing plane; the polishing plane is at a preset position away from the core of the gain fiber, and then the prepared nonlinear wavelength conversion material is transferred to the polishing plane to obtain a wavelength converter. In this method, the gain fiber including the polishing plane is obtained by polishing the gain fiber, and the prepared nonlinear wavelength conversion material is attached to the polishing plane. By introducing the nonlinear wavelength conversion material, the nonlinear wavelength conversion material is attached to the polishing plane of the gain fiber, which significantly enhances the second-order nonlinear effect of the gain fiber. When the optical frequency comb of the 1530nm band in the mode-locked laser is incident on the gain fiber, the optical frequency comb of the 1530nm band interacts with the nonlinear wavelength conversion material, and the optical frequency comb of the 765nm band is output through second harmonic generation, thereby realizing efficient optical frequency comb generation near the 765nm band.

[0061] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0062] Based on the same inventive concept, the embodiment of the present application also provides a wavelength converter manufacturing device for implementing the wavelength converter manufacturing method involved above. The implementation solution provided by the device to solve the problem is similar to the implementation solution recorded in the above method, so the specific limitations in one or more wavelength converter manufacturing device embodiments provided below can refer to the limitations of the wavelength converter manufacturing method above, and will not be repeated here.

[0063] In an exemplary embodiment, as shown in FIG. 4 , a wavelength converter manufacturing device 1 is provided, comprising: an optical fiber polishing module 20 and a material transfer module 30, wherein:

[0064] The optical fiber polishing module 20 is used to polish the cladding of one side of the gain optical fiber to obtain a gain optical fiber including a polishing plane; the polishing plane is at a preset position away from the core of the gain optical fiber;

[0065] The material transfer module 30 is used to transfer the prepared nonlinear wavelength conversion material to the polishing surface to obtain a wavelength converter.

[0066] In one embodiment, the material transfer module 30 is further configured to:

[0067] The tape carrying the thin sheet is adhered to the polydimethylsiloxane (PDMS) on the glass slide to obtain a nanosheet with a thickness of a single atomic layer; the glass slide carrying the nanosheet and PDMS is assembled on a three-dimensional translation stage; the PDMS is placed under the nanosheet; the three-dimensional translation stage is moved to the sample stage where the gain fiber is fixed, and the temperature of the translation stage is increased until the PDMS loses its viscosity, and then the nonlinear wavelength conversion material is transferred to the polished surface of the gain fiber.

[0068] Each module in the above-mentioned wavelength converter manufacturing device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0069] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0070] Polishing one side cladding of the gain optical fiber to obtain a gain optical fiber including a polishing plane; the polishing plane is at a preset position away from the core of the gain optical fiber;

[0071] The prepared nonlinear wavelength conversion material is transferred to a polished surface to obtain a wavelength converter.

[0072] In one embodiment, the sheet of nonlinear wavelength conversion material is on the tape, and when the processor executes the logic in the computer program to transfer the prepared nonlinear wavelength conversion material to the polishing plane, the following steps can be implemented:

[0073] The tape carrying the thin sheet is adhered to the polydimethylsiloxane (PDMS) on the glass slide to obtain a nanosheet with a thickness of a single atomic layer;

[0074] Assemble the glass slide carrying the nanosheet and PDMS on a three-dimensional translation stage; PDMS is located below the nanosheet;

[0075] The three-dimensional translation stage is moved to the sample stage where the gain optical fiber is fixed, and the temperature of the translation stage is increased until the PDMS loses its viscosity, and then the nonlinear wavelength conversion material is transferred to the polished surface of the gain optical fiber.

[0076] The implementation principles and technical effects of each step implemented by the processor in the embodiment of the present application are similar to the principles of the above-mentioned wavelength converter preparation method, and will not be repeated here.

[0077] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0078] Polishing one side cladding of the gain optical fiber to obtain a gain optical fiber including a polishing plane; the polishing plane is at a preset position away from the core of the gain optical fiber;

[0079] The prepared nonlinear wavelength conversion material is transferred to a polished surface to obtain a wavelength converter.

[0080] In one embodiment, the sheet of nonlinear wavelength conversion material is on an adhesive tape, and when the logic of transferring the prepared nonlinear wavelength conversion material to the polishing surface in the computer program is executed by the processor, the following steps can be implemented:

[0081] The tape carrying the thin sheet is adhered to the polydimethylsiloxane (PDMS) on the glass slide to obtain a nanosheet with a thickness of a single atomic layer;

[0082] Assemble the glass slide carrying the nanosheet and PDMS on a three-dimensional translation stage; PDMS is located below the nanosheet;

[0083] The three-dimensional translation stage is moved to the sample stage where the gain optical fiber is fixed, and the temperature of the translation stage is increased until the PDMS loses its viscosity, and then the nonlinear wavelength conversion material is transferred to the polished surface of the gain optical fiber.

[0084] The implementation principles and technical effects of the steps implemented when the computer program in the embodiment of the present application is executed by the processor are similar to the principles of the above-mentioned wavelength converter preparation method, and will not be repeated here.

[0085] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the following steps:

[0086] Polishing one side cladding of the gain optical fiber to obtain a gain optical fiber including a polishing plane; the polishing plane is at a preset position away from the core of the gain optical fiber;

[0087] The prepared nonlinear wavelength conversion material is transferred to a polished surface to obtain a wavelength converter.

[0088] In one embodiment, the sheet of nonlinear wavelength conversion material is on an adhesive tape, and when the logic of transferring the prepared nonlinear wavelength conversion material to the polishing surface in the computer program is executed by the processor, the following steps can be implemented:

[0089] The tape carrying the thin sheet is adhered to the polydimethylsiloxane (PDMS) on the glass slide to obtain a nanosheet with a thickness of a single atomic layer;

[0090] Assemble the glass slide carrying the nanosheet and PDMS on a three-dimensional translation stage; PDMS is located below the nanosheet;

[0091] The three-dimensional translation stage is moved to the sample stage where the gain optical fiber is fixed, and the temperature of the translation stage is increased until the PDMS loses its viscosity, and then the nonlinear wavelength conversion material is transferred to the polished surface of the gain optical fiber.

[0092] The implementation principles and technical effects of the steps implemented when the computer program in the embodiment of the present application is executed by the processor are similar to the principles of the above-mentioned wavelength converter preparation method, and will not be repeated here.

[0093] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0094] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0095] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0096] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A wavelength converter, characterized in that: The wavelength converter includes a gain optical fiber and a nonlinear wavelength conversion material; the nonlinear wavelength conversion material is attached to the polished surface of the gain optical fiber; When an optical frequency comb with an initial central wavelength is incident on the gain optical fiber, an optical frequency comb with a preset central wavelength is generated by the nonlinear wavelength conversion material.

2. The wavelength converter according to claim 1, characterized in that: The polished plane of the gain optical fiber is a polished surface of a D-shaped optical fiber obtained by polishing the cladding of the gain optical fiber.

3. The wavelength converter according to claim 1 or 2, characterized in that: The gain optical fiber is a single-mode optical fiber.

4. The wavelength converter according to claim 1 or 2, characterized in that: The nonlinear wavelength conversion material is a single layer of tungsten diselenide.

5. The wavelength converter according to claim 1 or 2, characterized in that: The initial central wavelength is in the 1530nm band; the preset central wavelength is in the 765nm band.

6. The wavelength converter according to claim 1 or 2, characterized in that: The gain optical fiber has a core refractive index of 1.4504, a core diameter of 9 um, and a cladding refractive index of 1.4437.

7. An optical frequency comb generating device in the visible light band, characterized in that: The device comprises a mode-locked laser and a wavelength converter as claimed in any one of claims 1 to 6.

8. The device according to claim 7, characterized in that The central wavelength of the optical frequency comb generated by the mode-locked laser is in the 1530nm band; the visible light band is in the 765nm band.

9. A method for preparing a wavelength converter, characterized in that: The method comprises: Polishing one side cladding of the gain optical fiber to obtain a gain optical fiber including a polishing plane; the polishing plane is at a preset position away from the core of the gain optical fiber; The prepared nonlinear wavelength conversion material is transferred to the polished surface to obtain the wavelength converter.

10. The method according to claim 9, characterized in that The sheet of the nonlinear wavelength conversion material is on the tape; and the step of transferring the prepared nonlinear wavelength conversion material to the polishing plane comprises: The tape carrying the thin sheet is adhered to polydimethylsiloxane (PDMS) on a glass slide to obtain a nanosheet with a thickness of a single atomic layer; Assembling a glass slide carrying the nanosheet and the PDMS on a three-dimensional displacement stage; the PDMS is located below the nanosheet; The three-dimensional translation stage is moved to the sample stage where the gain optical fiber is fixed, and the temperature of the translation stage is increased until the PDMS loses its viscosity, and then the nonlinear wavelength conversion material is transferred to the polished surface of the gain optical fiber.

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