A self-pulsing laser and a pulse generating method

Abstract

The embodiment of the present invention discloses a self-pulsing laser and a pulse generation method. The self-pulsing laser includes a pump source, a polarization controller, a circulator, an optical fiber and an optical microcavity; the optical fiber includes a tapered structure, and the optical fiber is coupled to the optical microcavity through the tapered structure; the optical microcavity includes a substrate and a support column and a cavity located on one side of the substrate; the pump light emitted by the pump source is coupled into the optical fiber after passing through the polarization controller and the circulator; the polarization controller is used to adjust the polarization direction of the pump light; the pump light is coupled into the optical microcavity through the tapered structure, and the coupling strength between the pump light and the optical microcavity is changed by adjusting the distance between the tapered structure and the optical microcavity, and the pump light alternately generates Brillouin scattering and thermo-optical effect in the optical microcavity to form self-pulsing oscillation. The technical solution of the embodiment of the present invention utilizes a new relaxation oscillation phenomenon generated by Brillouin scattering and thermo-optical effect, and the optical microcavity process used is simple, which reduces the difficulty of generating self-pulsing lasers.

Description

Technical Field

[0001] The embodiments of the present invention relate to laser technology, and in particular to a self-pulsing laser and a pulse generating method. Background Art

[0002] Whispering gallery optical microcavities have ultra-high quality factors and low mode volumes. They can confine light in the microcavity and enhance the interaction between light and matter. This has greatly advanced research in the fields of optical cavity mechanics, cavity quantum mechanics, Kerr light combs, narrow linewidth lasers, and integrated photonics.

[0003] Brillouin lasers generated based on optical microcavities are widely used in the research of microwave photonics, integrated gyroscopes, high-performance optical frequency combs, etc. due to their good narrow linewidth characteristics. Lasers can be divided into continuous lasers and pulsed lasers according to the different time domain characteristics of laser output. Currently, the Brillouin lasers generated in optical microcavities that are widely used are all continuous lasers, but pulsed lasers are lacking. Self-pulsing Brillouin lasers are often difficult to achieve in optical microcavities. The main reason is that the laser system that generates self-pulsations in optical microcavities has a complex structure and is difficult to operate. In addition, the difficulty in preparing optical microcavity samples used to obtain self-pulsing lasers in optical microcavities and the existence of factors such as difficulty in widespread promotion make the production of self-pulsing lasers based on optical microcavities difficult. Summary of the invention

[0004] The embodiment of the present invention provides a self-pulsating laser and a pulse generating method, so as to reduce the difficulty of producing the self-pulsating laser and simplify the process flow of producing the self-pulsating laser in a microcavity.

[0005] In a first aspect, an embodiment of the present invention provides a self-pulsating laser, comprising: a pump source, a polarization controller, a circulator, an optical fiber, and an optical microcavity;

[0006] The output end of the pump source is connected to the input end of the polarization controller, the output end of the polarization controller is connected to the first end of the circulator, and the second end of the circulator is connected to the optical fiber;

[0007] The optical fiber extends from the second end of the circulator to the optical microcavity, the optical fiber extending to the optical microcavity comprises a tapered structure, and the optical fiber is coupled to the optical microcavity through the tapered structure;

[0008] Wherein, the optical microcavity comprises a substrate and a support column and a cavity located on one side of the substrate;

[0009] The pump light emitted by the pump source is coupled into the optical fiber after passing through the polarization controller and the circulator;

[0010] The polarization controller is used to adjust the polarization direction of the pump light;

[0011] The pump light is coupled into the optical microcavity through the conical structure, and the coupling strength between the pump light and the optical microcavity is changed by adjusting the distance between the conical structure and the optical microcavity. The pump light alternately generates Brillouin scattering and thermo-optical effect in the optical microcavity to form self-pulse oscillation;

[0012] The pulse light generated by the self-pulse oscillation is coupled into the optical fiber, input from the second end of the circulator, and output from the third end of the circulator.

[0013] Optionally, it further includes an optical amplifier disposed between the pump source and the polarization controller, wherein the optical amplifier is used to amplify the pump light.

[0014] Optionally, the optical amplifier is a semiconductor optical amplifier;

[0015] The self-pulsing laser further includes a first collimator, an optical isolator and a second collimator;

[0016] The first collimator, the semiconductor optical amplifier, the optical isolator and the second collimator are arranged in sequence along the optical path between the pump source and the polarization controller;

[0017] The input end of the first collimator is coupled to the output end of the pump source, and is used to collimate the pump light and then input it into the semiconductor optical amplifier;

[0018] The semiconductor optical amplifier is used to amplify the pump light;

[0019] The optical isolator is used to enable the amplified pump light to be transmitted unidirectionally;

[0020] The output end of the second collimator is connected to the input end of the polarization controller.

[0021] Optionally, the optical amplifier is a fiber amplifier;

[0022] The pump source is connected to the input end of the optical fiber amplifier;

[0023] The output end of the optical fiber amplifier is connected to the polarization controller.

[0024] Optionally, the self-pulsing laser further includes a coupler, a first photodetector, a second photodetector, an oscilloscope and a spectrometer;

[0025] The optical fiber extending from the optical microcavity is connected to the first photodetector, the input end of the coupler is connected to the third end of the circulator, the first output end of the coupler is connected to the second photodetector, and the second output end is connected to the spectrometer, the spectrometer is used to measure the output spectrum of the second output end of the coupler, the first photodetector and the second photodetector are both connected to the oscilloscope, and the oscilloscope is used to output the time domain waveforms detected by the first photodetector and the second photodetector.

[0026] Optionally, the optical fiber and the optical microcavity are integrated on the same base substrate.

[0027] Optionally, the pump source includes a laser with a fixed wavelength.

[0028] Optionally, the substrate material of the optical microcavity includes silicon, and the material of the cavity includes silicon dioxide.

[0029] In a second aspect, an embodiment of the present invention further provides a pulse generation method, using the above-mentioned self-pulsing laser to output pulses, comprising:

[0030] The pump source outputs pump light, and the pump light is coupled into the optical microcavity through the optical fiber;

[0031] The power and polarization state of the pump light are adjusted so that the pump light alternately generates Brillouin scattering and thermo-optical effect in the optical microcavity to form a self-pulse oscillation output pulse.

[0032] The self-pulsating laser provided by the embodiment of the present invention comprises a pump source, a polarization controller, a circulator, an optical fiber and an optical microcavity; wherein the optical fiber of the optical microcavity comprises a tapered structure, the optical fiber can be coupled with the optical microcavity through the tapered structure, and the optical microcavity comprises a substrate and a support column and a cavity located on one side of the substrate. The pump light is coupled into the optical microcavity through the conical structure in the optical fiber, and the coupling efficiency of the pump light and the optical microcavity is changed by adjusting the distance between the conical structure and the optical microcavity. When the pump light power exceeds the threshold of Brillouin scattering, Brillouin scattering is first generated in the optical microcavity; with the generation of Brillouin laser, the intracavity energy of the optical microcavity increases, the temperature of the optical microcavity rises, causing the cavity mode to undergo thermal red shift, and the frequency detuning of the pump light increases; then the Stokes light field generated by stimulated Brillouin scattering changes with the change of the frequency detuning of the pump light, and when the frequency detuning of the pump light is too large, the Brillouin laser disappears; with the disappearance of the Brillouin laser, the optical microcavity cools, the cavity mode returns to the initial position, and after completing one self-pulsation oscillation, it is ready to start the next cycle of self-pulsation oscillation, thereby realizing the self-pulsation Brillouin laser on the optical microcavity chip. The self-pulsation laser provided in this embodiment has a simple process flow in the optical microcavity, reduces the difficulty of generating the self-pulsation laser, and further broadens the application of the self-pulsation Brillouin laser in laser radar and ranging. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the structure of a self-pulsating laser provided by an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of the structure of another self-pulsating laser provided by an embodiment of the present invention;

[0035] Figure 3 A schematic diagram of the structure of another self-pulsating laser provided by an embodiment of the present invention;

[0036] Figure 4 A schematic diagram of the structure of another self-pulsating laser provided by an embodiment of the present invention;

[0037] Figure 5 A schematic diagram of the structure of another self-pulsating laser provided by an embodiment of the present invention;

[0038] Figure 6 A schematic diagram of the structure of an optical microcavity provided by an embodiment of the present invention;

[0039] Figure 7 A schematic flow chart of a pulse generating method provided by an embodiment of the present invention;

[0040] Figure 8 Schematic diagram of the transmission spectra of pump light and Brillouin laser in an embodiment of the present invention;

[0041] Fig. 9 The figure is a schematic diagram of the spectrometer collecting the spectrum of pump light and Brillouin laser in the embodiment of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0043] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. It should be noted that the directional words such as "upper", "lower", "left", "right" and the like described in the embodiments of the present invention are described at the angles shown in the accompanying drawings and should not be understood as limitations on the embodiments of the present invention. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is formed "on" or "under" another element, it can not only be directly formed "on" or "under" another element, but also indirectly formed "on" or "under" another element through an intermediate element. The terms "first", "second" and the like are only used for descriptive purposes and do not indicate any order, quantity or importance, but are only used to distinguish different components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0044] Figure 1 FIG. 2 is a schematic diagram of the structure of a self-pulsating laser provided by an embodiment of the present invention. Figure 1 The self-pulsating laser provided in this embodiment includes a pump source 10, a polarization controller 20, a circulator 30, an optical fiber 40 and an optical microcavity 50; the output end of the pump source 10 is connected to the input end of the polarization controller 20, the output end of the polarization controller 20 is connected to the first end of the circulator 30, and the second end of the circulator 30 is connected to the optical fiber 40; the optical fiber 40 extends from the second end of the circulator 30 to the optical microcavity 50, and the optical fiber 40 extending to the optical microcavity 50 includes a tapered structure ( Figure 1 (not shown in the figure), the optical fiber 40 is coupled to the optical microcavity 50 through a tapered structure; wherein the optical microcavity 50 includes a substrate and a support column and a cavity located on one side of the substrate; the pump light emitted by the pump source 10 is coupled into the optical fiber 40 after passing through the polarization controller 20 and the circulator 30; the polarization controller 20 is used to adjust the polarization direction of the pump light; the pump light is coupled into the optical microcavity 50 through the tapered structure, and the pump light alternately generates Brillouin scattering and thermo-optical effect in the optical microcavity 50 to form self-pulse oscillation; the pulse light generated by the self-pulse oscillation is coupled into the optical fiber 40, and is input from the second end of the circulator 30 and output from the third end of the circulator 30.

[0045] In this embodiment, the pump source 10 may include a fixed wavelength laser, which can output a fixed wavelength pump light within a preset wavelength range, such as a pump light in the 1550nm band. It is understandable that, since lasers have many advantages such as high brightness, good directivity, and good monochromaticity, in a specific implementation, the fixed wavelength laser in the pump source 10 can output high-power pump light through an optical fiber. The pump source 10, the polarization controller 20, and the circulator 30 can be connected by an optical fiber 40.

[0046] Optionally, the optical microcavity 50 is an on-chip integrated device, and the optical fiber 40 and the optical microcavity 50 can be integrated on the same substrate. It can be understood that the light transmitted in the optical fiber 40 generates an evanescent field in the tapered structure to achieve coupling between the optical microcavity 50 and the optical fiber 40, and the tapered structure can be obtained by melting and tapering the optical fiber. By controlling the distance between the tapered structure and the optical microcavity 50, the coupling efficiency between the pump light and the optical microcavity 50 can be adjusted. The polarization state of the pump light is controlled by the polarization controller 20, wherein the polarization controller 20 can adopt a three-ring polarization controller.

[0047] Among them, Brillouin scattering is a common nonlinear phenomenon in whispering gallery optical microcavities. It originates from the interaction between the laser electric field and the acoustic wave field in molecules or solids, that is, the interaction between photons and phonons, also known as phonon scattering. Under the action of the laser electric field, the medium undergoes periodic changes in density and dielectric constant through the electrostrictive effect, inducing an acoustic wave field, which leads to a coherent scattering process between the incident light and the acoustic wave field. In other words, when a pump photon is annihilated, a Stokes photon and a phonon are generated at the same time. The method of generating the Brillouin scattering phenomenon requires two optical modes with an interval of exactly the Brillouin frequency shift, one as a pump mode to excite the other Brillouin mode, and observe the Brillouin laser in the reverse optical path. Brillouin laser can effectively narrow the line width of the pump laser, and can realize a narrow line width laser, which has important applications in the manufacture of gyroscopes, etc.

[0048] Self-pulsation oscillation is caused by uneven gain or uneven absorption inside the laser. When the injected current reaches a certain range, the output laser will experience continuous high-frequency oscillation of equal amplitude. In the prior art, some scholars have observed self-pulsation oscillation in erbium-doped micro-ring core lasers. This technology uses an erbium ion concentration of 2e19ion / cm 3The doped micro-ring core cavity has a main diameter of 43μm. By using cross relaxation between ions and incident 1444.8nm pump light, pulse light with a wavelength of 1560.2nm is generated. The so-called cross relaxation means that when the concentration of erbium ions is too high, the distance between ions decreases, and the ion-ion interaction is enhanced, resulting in energy transfer between ions, causing one ion to return to the ground state, preventing the complete reversal of the ion pair. At this time, the ion pair is equivalent to a saturated absorber. This saturated absorber makes the laser system very unstable, resulting in the generation of self-pulsation oscillation. However, the current self-pulsation laser system based on microcavity is complex and difficult to operate, and the microcavity samples used are difficult to prepare and not easy to promote.

[0049] In this embodiment, the applicant discovered a new type of relaxation oscillation phenomenon in the microcavity caused by the competition between Brillouin scattering and thermo-optical effect, and based on this, realized an on-chip self-pulsing Brillouin laser, and the micro-disk cavity process used is simple, which reduces the difficulty of generating self-pulsing lasers. Specifically, the process of forming self-pulsing oscillation by alternating Brillouin scattering and thermo-optical effect in the optical microcavity 50 by pump light can be divided into four stages. In the first stage, the response speed of stimulated Brillouin scattering in the optical microcavity is faster than that of the thermo-optical effect. When the frequency of the pump light is fixed, as the pump light power continues to increase, when the pump light power exceeds the threshold of the Brillouin laser, the Brillouin laser is observed first; in the second stage, as the Brillouin laser is generated, the energy in the cavity of the optical microcavity 50 increases, the temperature of the optical microcavity 50 rises, causing the cavity mode to undergo thermal red shift, and the pump light frequency detuning increases; in the third stage, the Stokes light field generated by stimulated Brillouin scattering changes with the change of the pump light frequency detuning. When the pump light frequency detuning is too large, the Brillouin laser disappears; in the fourth stage, as the Brillouin laser disappears, the optical microcavity 50 cools down, the cavity mode returns to the initial position, and after completing one self-pulsation oscillation, it is ready to start the next cycle of self-pulsation oscillation. Brillouin scattering and thermo-optical effect are generated alternately, thereby exciting pulses.

[0050] The technical solution of this embodiment provides pump light through a pump source with a fixed wavelength, adjusts the polarization state of the pump light through a polarization controller, couples the pump light into the optical microcavity through a tapered structure in the optical fiber, and changes the coupling efficiency between the pump light and the optical microcavity by adjusting the distance between the tapered structure and the optical microcavity. When the pump light power exceeds the threshold of Brillouin scattering, Brillouin scattering is first generated in the optical microcavity; with the generation of Brillouin laser, the intracavity energy of the optical microcavity increases, the temperature of the optical microcavity rises, causing the cavity mode to thermally redshift, and at the same time, the frequency detuning of the pump light increases; then, the Stokes light field generated by stimulated Brillouin scattering changes with the change of the frequency detuning of the pump light, and when the frequency detuning of the pump light is too large, the Brillouin laser disappears; with the disappearance of the Brillouin laser, the optical microcavity cools, the cavity mode returns to the initial position, and after completing one self-pulsation oscillation, it is ready to start the next cycle of self-pulsation oscillation, thereby realizing self-pulsation Brillouin laser on the optical microcavity chip. The self-pulsating laser provided in this embodiment has a simple process flow in the optical microcavity, which reduces the difficulty of generating the self-pulsating laser and further broadens the application of the self-pulsating Brillouin laser in laser radar and ranging.

[0051] Based on the above technical solutions, Figure 2 FIG. 2 is a schematic diagram of the structure of another self-pulsating laser provided by an embodiment of the present invention. Figure 2 Optionally, the self-pulsing laser further includes an optical amplifier 11 disposed between the pump source 10 and the polarization controller 20, and the optical amplifier is used to amplify the pump light.

[0052] It is understandable that, in a specific implementation, the power of the pump light output by the pump source 10 may be relatively small and cannot reach the threshold power of the pump light that can stimulate Brillouin laser. Therefore, an optical amplifier 11 may be provided on the optical path between the pump source 10 and the polarization controller 20 to amplify the power of the pump light to above the threshold power.

[0053] Figure 3 FIG. 2 is a schematic diagram of the structure of another self-pulsating laser provided by an embodiment of the present invention. Figure 3 Optionally, the optical amplifier 11 is a semiconductor optical amplifier; the self-pulsing laser also includes a first collimator 12, an optical isolator 13 and a second collimator 14; the first collimator 12, the semiconductor optical amplifier, the optical isolator 13 and the second collimator 14 are arranged in sequence along the optical path between the pump source 10 and the polarization controller 20; the input end of the first collimator 12 is coupled with the output end of the pump source 10, and is used to collimate the pump light and input it into the semiconductor optical amplifier; the semiconductor optical amplifier is used to amplify the pump light; the optical isolator 13 is used to make the amplified pump light unidirectionally transmitted; the output end of the second collimator 14 is connected to the input end of the polarization controller 20.

[0054] It can be understood that semiconductor optical amplifiers generally transmit light beams in free space. The pump source 10 can output pump light through the optical fiber 40. After passing through the first collimator 12, the transmission light in the optical fiber 40 is converted into parallel light in free space, and the pump light is gain amplified after the optical power is increased by the semiconductor optical amplifier. After passing through the optical isolator 13, the amplified pump light can only be transmitted in the forward direction to prevent the back-reflected light from damaging the semiconductor optical amplifier. After passing through the second collimator 14, the power-amplified free space parallel light is re-coupled into the optical fiber 40 for continued transmission.

[0055] In another embodiment, optionally, the optical amplifier 11 is a fiber amplifier; the pump source 10 is connected to the input end of the fiber amplifier; and the output end of the fiber amplifier is connected to the polarization controller 20 .

[0056] It is understandable that the optical amplifier 11 may also be an optical fiber amplifier, and the optical path is only transmitted in the optical fiber 40, which reduces the coupling difficulty of the optical path. In other embodiments, other types of optical amplifiers may also be selected, and the embodiment of the present invention is not limited to this.

[0057] Figure 4 FIG. 2 is a schematic diagram of the structure of another self-pulsating laser provided by an embodiment of the present invention. Figure 4 Optionally, the self-pulsing laser further includes an adjustable attenuator 15 disposed between the optical amplifier 11 and the polarization controller 20, and the adjustable attenuator 15 is used to adjust the output power of the amplified pump light.

[0058] Figure 5 FIG. 2 is a schematic diagram of the structure of another self-pulsating laser provided by an embodiment of the present invention. Figure 5 Optionally, the self-pulsing laser further includes a coupler 60, a first photodetector 70, a second photodetector 80, an oscilloscope 90 and a spectrometer 100; the optical fiber 40 extending from the optical microcavity 50 is connected to the first photodetector 70, the input end of the coupler 60 is connected to the third end of the circulator 30, the first output end of the coupler 60 is connected to the second photodetector 80, the second output end is connected to the spectrometer 100, the spectrometer 100 is used to measure the output spectrum of the second output end of the coupler 60, the first photodetector 70 and the second photodetector 80 are both connected to the oscilloscope 90, and the oscilloscope 90 is used to output the time domain waveform detected by the first photodetector 70 and the second photodetector 80.

[0059] It can be understood that the pump light passing through the circulator 30 enters the optical microcavity 50 after being coupled through the conical structure from the second output end of the circulator 30, the transmitted pump light is detected by the first photodetector 70 and monitored by the oscilloscope 90, and the reverse Brillouin laser is output through the third output port of the circulator 30 and then enters the coupler for branching, one of which directly enters the spectrometer 100, and the other is detected by the second photodetector 80, and finally connected to the oscilloscope 90 for observation.

[0060] Optionally, the substrate material of the optical microcavity 50 in the self-pulsating laser includes silicon, and the material of the cavity includes silicon dioxide.

[0061] It is understandable that the selected Brillouin frequency shift is about 10.8 GHz, and the Brillouin frequency shift in the silica material is also close to 10.8 GHz. In other words, the substrate and cavity material of the optical microcavity 50 is made of silica, which ensures that the Brillouin frequency of the silica material is close to the frequency corresponding to the pump mode and the Brillouin mode spacing.

[0062] For example, Figure 6 FIG. 1 is a schematic diagram of the structure of an optical microcavity provided by an embodiment of the present invention. Figure 6 The optical microcavity includes a substrate 51, a support column 52 and a microdisk cavity 53 located on one side of the substrate. The substrate 51 and the support column 52 can be made of silicon, and the microdisk cavity 53 can be made of silicon dioxide. In this embodiment, the microdisk cavity 53 is truncated cone-shaped, and the truncated cone is coupled to the optical fiber through the conical structure of the optical fiber.

[0063] Figure 7 FIG. 1 is a flow chart of a pulse generation method provided by an embodiment of the present invention. The pulse is generated by any one of the self-pulsing lasers provided by the above embodiments. Figure 7 , the pulse generating method comprises:

[0064] Step S110: The pump source outputs pump light, and the pump light is coupled into the optical microcavity through the optical fiber.

[0065] Step S120, adjusting the power and polarization state of the pump light so that the pump light generates Brillouin scattering and thermo-optical effect alternately in the optical microcavity to form a self-pulsation oscillation output pulse.

[0066] For example, in one embodiment of the present invention, a pump light near the 1550nm band is selected, and the optical microcavity is a silicon oxide microdisk cavity with a diameter of 2.7mm and a free spectrum region FSR of about 24.5GHz. The microdisk cavity is completed by photolithography, hydrofluoric acid etching, xenon difluoride etching and other steps. Figure 8The figure shows a schematic diagram of the transmission spectrum of the pump light and Brillouin laser provided by an embodiment of the present invention. After the pump mode and Brillouin mode are selected, the pump light power is slowly increased to exceed the threshold of the Brillouin laser. At the same time, the coupling between the microcavity and the tapered structure of the optical fiber and the polarization of the pump light are adjusted. As the power of the reverse optical path slowly increases, the Brillouin laser is generated. Then the power is slowly increased. When the pump power reaches about 50mW, the pump light and the reverse Brillouin laser simultaneously exhibit self-pulsation oscillations. At the same time, the frequency detuning of the pump light continues to increase. When the frequency detuning of the pump light is too large, the Brillouin laser disappears, the microcavity cools, and the cavity mode returns to its original position. After completing one self-pulsation oscillation, it is ready to start the next cycle of self-pulsation oscillation. The oscillation period is about 12μs. Furthermore, changing the detuning of the pump light frequency can change the pulse period of the generated self-pulsation Brillouin laser. Fig. 9 The figure shows a schematic diagram of the spectrum of the pump light and the reverse Brillouin laser collected by the spectrometer in the embodiment of the present invention, wherein the pump light and the Brillouin laser can be observed from the spectrum diagram.

[0067] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A self-pulsating laser, characterized in that: Includes pump sources, polarization controllers, circulators, optical fibers, and optical microcavities; The output end of the pump source is connected to the input end of the polarization controller, the output end of the polarization controller is connected to the first end of the circulator, and the second end of the circulator is connected to the optical fiber; The optical fiber extends from the second end of the circulator to the optical microcavity, the optical fiber extending to the optical microcavity comprises a tapered structure, and the optical fiber is coupled to the optical microcavity through the tapered structure; Wherein, the optical microcavity comprises a substrate and a support column and a cavity located on one side of the substrate; The pump light emitted by the pump source is coupled into the optical fiber after passing through the polarization controller and the circulator; The polarization controller is used to adjust the polarization direction of the pump light; The pump light is coupled into the optical microcavity through the conical structure, and the coupling strength between the pump light and the optical microcavity is changed by adjusting the distance between the conical structure and the optical microcavity. The pump light alternately generates Brillouin scattering and thermo-optical effect in the optical microcavity to form self-pulse oscillation; The pulse light generated by the self-pulse oscillation is coupled into the optical fiber, input from the second end of the circulator, and output from the third end of the circulator.

2. The self-pulsating laser according to claim 1, characterized in that It also includes an optical amplifier disposed between the pump source and the polarization controller, and the optical amplifier is used to amplify the pump light.

3. The self-pulsating laser according to claim 2, characterized in that: The optical amplifier is a semiconductor optical amplifier; The self-pulsing laser further includes a first collimator, an optical isolator and a second collimator; The first collimator, the semiconductor optical amplifier, the optical isolator and the second collimator are arranged in sequence along the optical path between the pump source and the polarization controller; The input end of the first collimator is coupled to the output end of the pump source, and is used to collimate the pump light and then input it into the semiconductor optical amplifier; The semiconductor optical amplifier is used to amplify the pump light; The optical isolator is used to enable the amplified pump light to be transmitted unidirectionally; The output end of the second collimator is connected to the input end of the polarization controller.

4. The self-pulsating laser according to claim 2, characterized in that: The optical amplifier is a fiber amplifier; The pump source is connected to the input end of the optical fiber amplifier; The output end of the optical fiber amplifier is connected to the polarization controller.

5. The self-pulsating laser according to claim 2, characterized in that: It also includes an adjustable attenuator arranged between the optical amplifier and the polarization controller, and the adjustable attenuator is used to adjust the output power of the amplified pump light.

6. The self-pulsating laser according to any one of claims 1 to 5, characterized in that: Also includes a coupler, a first photodetector, a second photodetector, an oscilloscope, and a spectrometer; The optical fiber extending from the optical microcavity is connected to the first photodetector, the input end of the coupler is connected to the third end of the circulator, the first output end of the coupler is connected to the second photodetector, and the second output end is connected to the spectrometer, the spectrometer is used to measure the output spectrum of the second output end of the coupler, the first photodetector and the second photodetector are both connected to the oscilloscope, and the oscilloscope is used to output the time domain waveforms detected by the first photodetector and the second photodetector.

7. The self-pulsating laser according to claim 1, characterized in that: The optical fiber and the optical microcavity are integrated on the same base substrate.

8. The self-pulsating laser according to claim 1, characterized in that: The pump source includes a fixed wavelength laser.

9. The self-pulsating laser according to claim 1, characterized in that: The substrate material of the optical microcavity includes silicon, and the material of the cavity includes silicon dioxide.

10. A pulse generation method, characterized in that: The method of outputting pulses using the self-pulsing laser according to any one of claims 1 to 9 comprises: The pump source outputs pump light, and the pump light is coupled into the optical microcavity through the optical fiber; The power and polarization state of the pump light are adjusted so that the pump light alternately generates Brillouin scattering and thermo-optical effect in the optical microcavity to form a self-pulse oscillation output pulse.

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