Mode-locked laser and preparation method and device of electric control graphene device

Abstract

The invention relates to a mode-locked laser and an electric control graphene device preparation method and device. The mode-locked laser comprises an electric control graphene device; the electric control graphene device comprises graphene, two gold electrodes and a gain optical fiber, the graphene is attached to a polishing area of the gain optical fiber, and the two gold electrodes are in contact with the two sides of the graphene respectively; and an external power supply is connected with the mode-locked laser, and the magnitude of current introduced into the graphene is adjusted through the external power supply, so that the Fermi level of the graphene is regulated and controlled. The graphene is attached to the polishing area of the gain fiber, the two gold electrodes are in contact with the two sides of the graphene respectively to form a current injection structure, the external power supply is connected with the mode-locked laser, the magnitude of the current introduced into the graphene is adjusted through the external power supply, the Fermi level of the graphene can be effectively improved, and the reliability of the mode-locked laser is improved. Through graphene Fermi level regulation and control, the saturated absorption and refractive index of the graphene are tuned, so that the output characteristics of the laser are flexibly tuned.

Description

Technical Field

[0001] The present application relates to the field of laser technology, and in particular to a method and apparatus for preparing a mode-locked laser and an electrically controlled graphene device. Background Art

[0002] Mode-locked lasers are ultrashort pulse laser devices that can emit narrow pulse widths and high peak powers.

[0003] In related technologies, mode-locked lasers use mode-locking technology to create a definite phase relationship between longitudinal modes of laser oscillation at different frequencies, thereby generating extremely short laser pulses. They are widely used in the fields of micro-machining of electronic devices, automotive mold engraving, micro-machining and repair of molds.

[0004] However, the mode-locked lasers in related technologies have limited tunability in output wavelength and repetition rate, making it difficult to meet the growing demand for diversified applications. Summary of the invention

[0005] Based on this, it is necessary to provide a method and apparatus for preparing a mode-locked laser and an electrically controlled graphene device to address the above-mentioned technical problems, which can dynamically adjust the repetition rate and gain wavelength parameters of the laser to achieve precise tuning of the output wavelength and repetition rate in a small range of 1540-1560nm.

[0006] In a first aspect, an embodiment of the present application provides a mode-locked laser, the mode-locked laser comprising an electrically controlled graphene device; the electrically controlled graphene device comprises graphene, two gold electrodes and a gain fiber, the graphene is attached to a polished area of ​​the gain fiber, and the two gold electrodes are in contact with two sides of the graphene respectively;

[0007] An external power supply is connected to the mode-locked laser, and the current passing into the graphene is adjusted by the external power supply to control the Fermi level of the graphene.

[0008] In one of the embodiments, the electrically-controlled graphene device further comprises a resonant cavity; the resonant cavity comprises two high-reflection films, and the two high-reflection films are located at two ends of the resonant cavity.

[0009] In one embodiment, both high-reflection films are fiber Bragg gratings made based on gain optical fibers.

[0010] In one embodiment, the mode-locked laser further includes a pump laser, and the pump laser is used to generate pump light for exciting the gain fiber.

[0011] In one embodiment, the gain fiber is an erbium-doped fiber.

[0012] In one embodiment, the polished region of the gain optical fiber is a D-type region formed by polishing a cladding in a preset range of the gain optical fiber.

[0013] In a second aspect, the present application also provides a method for preparing an electrically controlled graphene device, the method comprising:

[0014] Highly reflective fiber Bragg gratings are prepared at both ends of the gain optical fiber, and the cladding of a preset range in the gain optical fiber is polished to obtain a gain optical fiber including the polished area;

[0015] The prepared graphene is transferred to the polishing area, and two gold electrodes are placed on both sides of the graphene to obtain an electrically controlled graphene device.

[0016] In one embodiment, a cladding in a preset range of a gain optical fiber is polished to obtain a gain optical fiber including a polished area, comprising:

[0017] Fix the gain optical fiber on the fixture and remove the coating layer of the gain optical fiber;

[0018] Roughly grinding the gain optical fiber using a grinding wheel with a preset mesh number to obtain a roughly ground gain optical fiber;

[0019] The grinding wheels with different mesh sizes are replaced, and the roughly ground gain optical fiber is finely ground and polished to obtain the gain optical fiber including the polished area.

[0020] In one embodiment, the gain optical fiber is roughly ground using a grinding wheel with a preset mesh number to obtain a roughly ground gain optical fiber, including:

[0021] When the gain fiber is passing light, the cladding of a preset range in the gain fiber is roughly ground according to the grinding wheel; 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 direction and controls the polishing length along the axial direction of the gain fiber;

[0022] When the rough grinding is determined to the core position of the gain optical fiber based on the transmission loss waveform monitored by the power meter, the rough grinding is stopped to obtain the gain optical fiber after rough grinding.

[0023] In a third aspect, the present application also provides an electrically controlled graphene device preparation device, comprising:

[0024] An optical fiber polishing module is used to prepare high-reflection fiber Bragg gratings at both ends of the gain optical fiber and polish the cladding of a preset range in the gain optical fiber to obtain a gain optical fiber including the polished area;

[0025] The graphene transfer module is used to transfer the prepared graphene to the polishing area and place two gold electrodes on both sides of the graphene to obtain an electrically controlled graphene device.

[0026] In a fourth 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 second aspect are implemented.

[0027] In a fifth 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 second aspect are implemented.

[0028] In a sixth 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 second aspect are implemented.

[0029] The mode-locked laser and the method and device for preparing the electrically controlled graphene device provided in the embodiment of the present application, the mode-locked laser includes an electrically controlled graphene device; the electrically controlled graphene device includes graphene, two gold electrodes and a gain fiber, the graphene is attached to the polished area of ​​the gain fiber, and the two gold electrodes are respectively in contact with the two sides of the graphene; an external power supply is connected to the mode-locked laser, and the magnitude of the current passed into the graphene is adjusted by the external power supply to regulate the Fermi level of the graphene. In the mode-locked laser, a current injection structure is formed by attaching the graphene to the polished area of ​​the gain fiber, and the two gold electrodes are respectively in contact with the two sides of the graphene, and the external power supply is connected to the mode-locked laser, and the magnitude of the current passed into the graphene is adjusted by the external power supply, so that the Fermi level of the graphene can be effectively improved, and the saturated absorption and refractive index of the graphene can be tuned by regulating the Fermi level of the graphene, thereby realizing flexible tuning of the output characteristics of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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.

[0031] Figure 1 is a schematic diagram of an electrically controlled graphene device in one embodiment;

[0032] Figure 2 is a schematic diagram of an electrically controlled graphene device in another embodiment;

[0033] Figure 3 is a schematic diagram of a performance testing system in one embodiment;

[0034] Figure 4Schematic diagram of a process for preparing an electrically controlled graphene device in one embodiment;

[0035] Figure 5 Schematic diagram of the structure of an apparatus for preparing an electrically controlled graphene device in one embodiment. DETAILED DESCRIPTION

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] Traditional mode-locked lasers have shown great potential in generating ultrashort pulses, but most devices have limited tunability in output wavelength and repetition rate, making it difficult to meet the growing demand for diverse applications. FP cavities are often used as laser resonant cavities because of their simple structure and easy adjustment. Graphene, as a new type of two-dimensional material, has ultrafast carrier dynamics and adjustable saturation absorption properties, making it an ideal material for realizing mode-locked lasers. However, how to effectively utilize the superior saturation absorption characteristics of graphene and combine the advantages of the FP cavity to construct a mode-locked laser with stable output, flexible and tunable output is still a major challenge in current research.

[0041] Based on this, the present application provides a mode-locked laser, which forms a current injection structure by attaching graphene to the polished area of ​​the gain optical fiber, and two gold electrodes are respectively in contact with the two sides of the graphene, and an external power supply is connected to the mode-locked laser. The magnitude of the current passed into the graphene is adjusted by the external power supply, which can effectively improve the Fermi level of the graphene. By regulating the Fermi level of graphene, the saturation absorption and refractive index of the graphene can be tuned, thereby achieving flexible tuning of the output characteristics of the laser.

[0042] In an exemplary embodiment, Figure 1 As shown, a mode-locked laser is provided, which includes an electrically controlled graphene device 10; the electrically controlled graphene device 10 includes graphene 11, two gold electrodes 12 and a gain fiber 13, the graphene 11 is attached to the polished area of ​​the gain fiber 13, and the two gold electrodes 12 are in contact with two sides of the graphene 11 respectively;

[0043] An external power source is connected to the mode-locked laser, and the magnitude of the current flowing into the graphene 11 is adjusted by the external power source to control the Fermi level of the graphene 11 .

[0044] Among them, the electrically controlled graphene device 10 refers to a graphene-based electronic device whose performance is controlled by an electric field. Such a device utilizes the excellent electrical properties of graphene to achieve specific functions.

[0045] In an embodiment of the present application, the electrically controlled graphene device 10 includes graphene 11, two gold electrodes 12 and a gain fiber 13. The gain fiber 13 is an erbium-doped fiber. The graphene 11 is attached to the polished area of ​​the gain fiber 13, wherein the polished area is a D-type area formed by polishing the cladding of a preset range in the gain fiber 13. For example, a diamond grinding wheel can be used to polish the cladding in the middle position of the gain fiber 13 to form a D-type area. The graphene 11 film is attached to the D-type area as a saturated absorber. Through its unique band structure and fast carrier relaxation process, the graphene 11 converts the 980nm laser into a 1550nm optical frequency comb, and realizes the formation and stabilization of the mode-locked pulse.

[0046] Two gold electrodes 12 are attached to both sides of the graphene 11 to form a current injection structure. By adjusting the current passed into the graphene through an external power supply, the Fermi level of the graphene can be effectively changed. The change in the Fermi level directly affects the carrier concentration and band structure of the graphene, thereby adjusting its refractive index and saturation absorption depth. This process allows the repetition rate and gain wavelength parameters of the laser to be dynamically adjusted, achieving precise tuning of the output wavelength and repetition rate within a small range of 1540-1560nm.

[0047] In one embodiment, if Figure 2As shown, the electrically-controlled graphene device 10 further includes a resonant cavity; the resonant cavity includes two high-reflection films 14, and the two high-reflection films 14 are located at two ends of the resonant cavity.

[0048] Among them, high-reflective film refers to a special film that plays a reflective role in optical devices. Its reflectivity is generally as high as over 99%, which can effectively reflect light back into the laser, thereby improving laser energy utilization and output power.

[0049] In the embodiment of the present application, both high-reflection films are fiber Bragg gratings prepared based on gain optical fiber. Exemplarily, a highly reflective fiber Bragg grating structure (FBG) is prepared on the core of an erbium-doped optical fiber using an ultraviolet laser phase mask method. During the ultraviolet exposure process, the positions of the optical fiber and the phase mask template relative to the ultraviolet laser spot are controlled to remain unchanged. As the exposure time increases, the change in the core refractive index of the optical fiber during the exposure process will cause the central wavelength of the FBG to gradually increase. A pair of FBGs are prepared on an erbium-doped optical fiber using an ultraviolet laser phase mask method. The parameter reflection bandwidth of the two FBGs is designed to be 1nm, the spacing is 60cm, and the reflectivity is greater than 99%, thereby forming a fiber-like Fabry-Perot resonant cavity (FP cavity). The FP cavity is used as the resonant cavity of the laser. The two sections of the cavity are composed of two high-reflectivity FBGs to ensure that the light is reflected multiple times in the cavity to enhance and form a stable resonance. The cavity material is preferably a low-loss, high-stability erbium fiber to support light amplification of a specific wavelength and enhance the laser output efficiency.

[0050] In one embodiment, the mode-locked laser also includes a pump laser, which is used to generate pump light for exciting the gain fiber. Exemplarily, a 980 nm pump laser is used as an excitation light source to connect to the electrically controlled graphene device 10 to form a graphene electrically controlled laser. The 980 nm laser is input into the micro-nano cavity after passing through a wavelength division multiplexer (WDM), absorbed by the erbium particles in the micro-nano cavity, and emits a 1550 nm laser. The 1550 nm laser resonates in the cavity. The light resonating in the cavity will be modulated by the saturated absorption of graphene, thereby forming a mode-locked pulse. The laser can output an optical frequency comb in the range of 1550 nm, and realize the tunable central wavelength in a small range through the electrically controlled graphene structure, and finally realize a mode-locked laser with a cavity length of 40 cm and a repetition rate of 250.92 MHz.

[0051] In this embodiment, the semi-metallic properties of graphene are utilized, and when graphene is transferred to the D-type region of the optical fiber, the initial doping state of graphene is p-type doping. Electrons are injected by an applied voltage to gradually change the doped state of graphene from the initial p-type doping to n-type doping, and the Fermi level of graphene is gradually transitioned from the valence band to the conduction band, and graphene presents a resistance change trend of first rising and then falling, thereby pairing the graphene Fermi level regulation. Through the control of the graphene Fermi level, the saturation absorption and refractive index of graphene are tuned, thereby realizing a tunable mode-locked laser around 1550nm. By precisely controlling the voltage, the output wavelength of the optical frequency comb laser can be adjusted in a small range near 1550nm, while maintaining the high quality and stability of the mode-locked pulse. In addition, by adjusting the current size, the repetition frequency of the laser pulse can also be flexibly adjusted to meet the needs of different application scenarios.

[0052] After preparing the electrically controlled graphene device, the embodiment of the present application also built a performance test system for optical characteristic parameters. The performance test system consists of a graphene electrically controlled mode-locked laser, a 980 / 1550 wavelength division multiplexer (WDM), a polarization controller, a 980nm pump laser source, a coupler, a photodetector, an oscilloscope, and a spectrometer. Figure 3 As shown in the figure, a 980 nm pump laser is used as an excitation light source, and a 980 nm wavelength laser is input as a test light source. The polarization controller can adjust the polarization state of the 980 nm laser to make it easier to enter the optical mode of the micro-nano cavity. The 980 nm laser is input into the laser after passing through the wavelength division multiplexer to generate a 1550 nm optical frequency comb laser. The laser then enters the coupler through the wavelength division multiplexer for light splitting, enters the oscilloscope to detect the power and repetition frequency indicators, and enters the spectrometer to detect the center wavelength of the spectrum.

[0053] The mode-locked laser provided in the embodiment of the present application comprises an electrically controlled graphene device; the electrically controlled graphene device comprises graphene, two gold electrodes and a gain fiber, the graphene is attached to the polished area of ​​the gain fiber, and the two gold electrodes are respectively in contact with the two sides of the graphene; an external power supply is connected to the mode-locked laser, and the magnitude of the current passed into the graphene is adjusted by the external power supply to regulate the Fermi level of the graphene. In the mode-locked laser, a current injection structure is formed by attaching the graphene to the polished area of ​​the gain fiber, and the two gold electrodes are respectively in contact with the two sides of the graphene, and the external power supply is connected to the mode-locked laser, and the magnitude of the current passed into the graphene is adjusted by the external power supply, so that the Fermi level of the graphene can be effectively improved, and the saturated absorption and refractive index of the graphene can be tuned by regulating the Fermi level of the graphene, thereby realizing flexible tuning of the output characteristics of the laser.

[0054] In an exemplary embodiment, Figure 4 As shown, the embodiment of the present application also provides a method for preparing an electrically controlled graphene device, comprising:

[0055] S101, preparing high-reflection fiber Bragg gratings at both ends of the gain optical fiber, and polishing a cladding in a preset range of the gain optical fiber to obtain a gain optical fiber including the polished area.

[0056] In the embodiment of the present application, a highly reflective fiber Bragg grating is prepared on the core of the gain optical fiber using an ultraviolet laser phase mask method, and a diamond grinding wheel with replaceable grain size is used to polish the cladding within a preset range in the gain optical fiber.

[0057] 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 polished area. The rough grinding process includes, while the gain fiber is passing light, rough grinding the cladding of a preset range in the gain fiber according to the grinding wheel; 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.

[0058] For example, a diamond grinding wheel with replaceable grit is used to polish the side of an erbium-doped optical fiber. To improve the surface smoothness of the polishing, the mesh number (the number of particles per unit area) of the grinding wheel is changed to achieve precise control of the processing depth and smoothness. 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 fine grind to improve the surface smoothness. Finally, a 12000 mesh is replaced for polishing to reduce the additional loss of light caused by surface scattering. To control the accuracy of polishing, a polishing control system consisting 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, a 980nm light source, and a power meter on the test bench fixture, passing light through the optical fiber, and using a power meter to monitor the transmission loss of the optical fiber. Select 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 core position, the optical signal in the 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 changes suddenly, stop the grinding wheel to control the appropriate rough grinding depth.

[0059] S102, transferring the prepared graphene to the polishing area, and placing two gold electrodes on both sides of the graphene, respectively, to obtain an electrically controlled graphene device.

[0060] In the embodiment of the present application, graphene needs to be prepared first, and then transferred to the polishing area of ​​the gain fiber after preparation. Exemplarily, the CVD method (chemical vapor deposition method) is selected to prepare a single-layer graphene of a larger area, and the number of layers, crystal size and other parameters of the graphene are controlled by precisely adjusting parameters (such as temperature, pressure, gas flow, etc.). Copper metal is selected as the catalytic metal substrate, and the copper foil is placed in a molten silica reaction tube, and the surface is treated by hydrogen annealing. A carbon source gas is introduced, and graphene is grown in a 1000 ° C environment for 40 minutes. Polymethyl Methacrylate (PMMA) is spin-coated on the surface as a supporting layer to form a single-layer graphene that can be directly transferred. The metal electrode for depositing graphene Fermi level regulation selects a gold electrode structure, and the gold electrodes as the source and drain are deposited by mask sputtering. The deposition thickness is 40nm, and it is deposited on the graphene surface to ensure good electrical contact and current injection efficiency.

[0061] After graphene is prepared, it is transferred to the D-shaped area of ​​the FP microcavity, and the prepared graphene is transferred to the polished surface of the D-shaped optical fiber using a wet transfer technique. The degree of adhesion between the graphene and the polished surface is improved by drying, and then the optical fiber structure is immersed in acetone to remove the PMMA support layer. Finally, two gold electrodes are placed on both sides of the graphene to obtain an electrically controlled graphene device.

[0062] The method for preparing an electrically controlled graphene device provided in the embodiment of the present application is to prepare a highly reflective fiber Bragg grating at both ends of a gain fiber, and to polish the cladding of a preset range in the gain fiber to obtain a gain fiber including a polished area, and then transfer the prepared graphene to the polished area, and place two gold electrodes on both sides of the graphene to obtain an electrically controlled graphene device. In this method, by attaching graphene to the polished area of ​​the gain fiber, and the two gold electrodes are in contact with both sides of the graphene, a current injection structure is formed to obtain an electrically controlled graphene device, and then an external power supply is connected to a mode-locked laser, and the magnitude of the current passed into the graphene is adjusted by the external power supply, which can effectively improve the Fermi level of the graphene, and by regulating the Fermi level of the graphene, the saturated absorption and refractive index of the graphene are tuned, thereby achieving flexible tuning of the output characteristics of the laser.

[0063] 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.

[0064] Based on the same inventive concept, the embodiment of the present application also provides an electrically controlled graphene device preparation device for implementing the above-mentioned electrically controlled graphene device preparation method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in one or more embodiments of the electrically controlled graphene device preparation device provided below can refer to the limitations of the electrically controlled graphene device preparation method above, and will not be repeated here.

[0065] In an exemplary embodiment, Figure 5 As shown, an electrically controlled graphene device preparation device 1 is provided, comprising: an optical fiber polishing module 20, a graphene transfer module 30, wherein:

[0066] The optical fiber polishing module 20 is used to prepare high-reflection fiber Bragg gratings at both ends of the gain optical fiber, and polish the cladding of a preset range in the gain optical fiber to obtain a gain optical fiber including the polished area;

[0067] The graphene transfer module 30 is used to transfer the prepared graphene to the polishing area and place two gold electrodes on both sides of the graphene to obtain an electrically controlled graphene device.

[0068] In one embodiment, the optical fiber polishing module 20 is further used for:

[0069] The gain optical fiber is fixed on the fixture, and the coating layer of the gain optical fiber is removed; the gain optical fiber is roughly ground using a grinding wheel with a preset mesh number to obtain a roughly ground gain optical fiber; the grinding wheel with a different mesh number is replaced, and the roughly ground gain optical fiber is finely ground and polished to obtain a gain optical fiber including a polished area.

[0070] In one embodiment, the optical fiber polishing module 20 is further used for:

[0071] When the gain fiber is passing light, the cladding of a preset range in the gain fiber is roughly ground according to the grinding wheel; 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 direction and controls the polishing length along the axial direction of the gain fiber;

[0072] When the rough grinding is determined to the core position of the gain optical fiber based on the transmission loss waveform monitored by the power meter, the rough grinding is stopped to obtain the gain optical fiber after rough grinding.

[0073] Each module in the above-mentioned electrically controlled graphene device preparation 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 operations corresponding to each of the above modules.

[0074] 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:

[0075] Highly reflective fiber Bragg gratings are prepared at both ends of the gain optical fiber, and the cladding of a preset range in the gain optical fiber is polished to obtain a gain optical fiber including the polished area;

[0076] The prepared graphene is transferred to the polishing area, and two gold electrodes are placed on both sides of the graphene to obtain an electrically controlled graphene device.

[0077] 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 method for preparing the electrically-controlled graphene device, and will not be repeated here.

[0078] 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:

[0079] Highly reflective fiber Bragg gratings are prepared at both ends of the gain optical fiber, and the cladding of a preset range in the gain optical fiber is polished to obtain a gain optical fiber including the polished area;

[0080] The prepared graphene is transferred to the polishing area, and two gold electrodes are placed on both sides of the graphene to obtain an electrically controlled graphene device.

[0081] The implementation principles and technical effects of the various 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 method for preparing the electrically-controlled graphene device, and will not be repeated here.

[0082] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the following steps:

[0083] Highly reflective fiber Bragg gratings are prepared at both ends of the gain optical fiber, and the cladding of a preset range in the gain optical fiber is polished to obtain a gain optical fiber including the polished area;

[0084] The prepared graphene is transferred to the polishing area, and two gold electrodes are placed on both sides of the graphene to obtain an electrically controlled graphene device.

[0085] The implementation principles and technical effects of the various 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 method for preparing the electrically-controlled graphene device, and will not be repeated here.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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 mode-locked laser, characterized in that: The mode-locked laser comprises an electrically controlled graphene device; the electrically controlled graphene device comprises graphene, two gold electrodes and a gain optical fiber, the graphene is attached to a polished area of ​​the gain optical fiber, and the two gold electrodes are in contact with two sides of the graphene respectively; An external power source is connected to the mode-locked laser, and the magnitude of the current flowing into the graphene is adjusted by the external power source to regulate the Fermi level of the graphene.

2. The mode-locked laser according to claim 1, characterized in that: The electrically controlled graphene device further comprises a resonant cavity; the resonant cavity comprises two high-reflection films, and the two high-reflection films are located at two ends of the resonant cavity.

3. The mode-locked laser according to claim 2, characterized in that: The two high-reflection films are both fiber Bragg gratings prepared based on the gain optical fiber.

4. The mode-locked laser according to any one of claims 1 to 3, characterized in that: The mode-locked laser further includes a pump laser, which is used to generate pump light for exciting the gain optical fiber.

5. The mode-locked laser according to any one of claims 1 to 3, characterized in that: The gain optical fiber is erbium-doped optical fiber.

6. The mode-locked laser according to any one of claims 1 to 3, characterized in that: The polished region of the gain optical fiber is a D-shaped region formed by polishing a cladding in a preset range in the gain optical fiber.

7. A method for preparing an electrically controlled graphene device, characterized in that: The method comprises: Preparing high-reflection fiber Bragg gratings at both ends of the gain optical fiber, and polishing a cladding in a preset range of the gain optical fiber to obtain a gain optical fiber including a polished area; The prepared graphene is transferred to the polishing area, and two gold electrodes are respectively placed on both sides of the graphene to obtain the electrically controlled graphene device.

8. The method according to claim 7, characterized in that The step of polishing the cladding of a preset range in the gain optical fiber to obtain a gain optical fiber including the polished area comprises: Fixing the gain optical fiber on a fixture, and removing the coating layer of the gain optical fiber; Roughly grinding the gain optical fiber using a grinding wheel with a preset mesh size to obtain a roughly ground gain optical fiber; The grinding wheels with different mesh sizes are replaced to perform fine grinding and polishing on the roughly ground gain optical fiber to obtain the gain optical fiber including the polished area.

9. The method according to claim 8, characterized in that The method of using a grinding wheel with a preset mesh number to roughly grind the gain optical fiber to obtain a roughly ground gain optical fiber comprises: When the gain optical fiber is passed through light, the cladding of a preset range in the gain optical fiber is roughly ground according to the grinding wheel; 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 direction and controls the polishing length along the axial direction of the gain optical fiber; When it is determined that the rough grinding reaches the core position of the gain optical fiber based on the transmission loss waveform monitored by the power meter, the rough grinding is stopped to obtain the roughly ground gain optical fiber.

10. An electrically controlled graphene device preparation device, characterized in that: The device comprises: An optical fiber polishing module, used for preparing high-reflection fiber Bragg gratings at both ends of the gain optical fiber, and polishing the cladding of a preset range in the gain optical fiber to obtain a gain optical fiber including a polished area; The graphene transfer module is used to transfer the prepared graphene to the polishing area, and place two gold electrodes on both sides of the graphene to obtain an electrically controlled graphene device.

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