Optical frequency comb generation system and generation method

Abstract

The embodiment of the present invention discloses an optical frequency comb generation system and generation method. The optical frequency comb generation system includes a pump source, a coupling structure and an optical force microcavity; the pump source is used to provide pump light; the coupling structure is used to couple the pump light into the optical force microcavity; the optical force microcavity includes an optical mode and a mechanical mode; the pump light excites the optical mode in the optical force microcavity; the optical mode is coupled with the mechanical mode to generate a dynamic reaction; the dynamic reaction drives the mechanical mode to generate an optical sideband and output an optical frequency comb; the pump light and the optical force microcavity are in a large blue detuned state, and the coupling structure and the optical force microcavity are in an over-coupled state. The large blue detuned state is that the difference between the pump light frequency and the optical mode resonance frequency is greater than ten times the mechanical mode resonance frequency, and the over-coupled state is that the optical mode loss rate is at the same order of magnitude as the mechanical mode resonance frequency. The technical solution of the present invention can generate a high-performance, wide-bandwidth, low-repetition-rate optical frequency comb for chip integration.

Description

Technical Field

[0001] The embodiments of the present invention relate to micro-nano optical device technology, and more particularly to an optical frequency comb generation system and generation method. Background Art

[0002] Optical frequency combs have important applications in modern optical measurement, high-precision spectroscopy, optical atomic clocks, microwave photonics and other fields.

[0003] Typically, optical frequency combs can be generated using mode-locked femtosecond lasers, electro-optic modulation, or Kerr nonlinearity. Compared with traditional mode-locked femtosecond lasers, electro-optic modulation or Kerr nonlinearity can realize optical frequency combs in microcavities, thereby achieving miniaturization and even chip integration. However, these microcavity optical frequency combs have high repetition rates (GHz to THz), which greatly limits their applications in high-resolution spectroscopy, effective molecular excitation, quantum optics, and ultra-narrow spectral width mode-locked pulse generation. The realization of low-repetition-rate microcavity optical frequency combs has traditionally been limited by size. For example, the previous lowest repetition rate of Kerr light combs was 1.859 GHz, generated from a 35 mm large-diameter microdisk cavity sample, while a larger sample is required for lower repetition rates. So far, there is no suitable solution for generating microcavity optical frequency combs with a repetition rate bandwidth of less than GHz, high efficiency, high coherence, spectral flatness, and applicable to all bands. Summary of the invention

[0004] Embodiments of the present invention provide an optical frequency comb generation system and generation method to generate a high-performance, wide-bandwidth, low-repetition-rate (<GHz) optical frequency comb that can be used for chip integration.

[0005] In a first aspect, an embodiment of the present invention provides an optical frequency comb generation system, including a pump source, a coupling structure, and an optical force microcavity;

[0006] The pump source is used to provide pump light, and the pump light is coupled into the coupling structure;

[0007] The coupling structure is used to couple the pump light into the optical force microcavity;

[0008] The optical force microcavity is integrated on a base substrate, and the optical force microcavity includes an optical mode and a mechanical mode;

[0009] The pump light excites the optical mode in the optical force microcavity;

[0010] The optical mode is coupled with the mechanical mode to generate a dynamic reaction;

[0011] The dynamic reaction drives the mechanical mode to generate optical sidebands and output an optical frequency comb;

[0012] Among them, the pump light and the optical force microcavity are in a large blue detuned state, and the coupling structure and the optical force microcavity are in an over-coupled state. The large blue detuned state means that the difference between the pump light frequency and the optical mode resonance frequency is greater than ten times the mechanical mode resonance frequency, and the over-coupled state means that the optical mode loss rate is at the same order of magnitude as the mechanical mode resonance frequency.

[0013] Optionally, a polarization controller is further included, wherein the polarization controller is located between the pump source and the coupling structure, and the polarization controller is used to adjust the polarization direction of the pump light.

[0014] Optionally, a beam splitter, a photodetector, an oscilloscope and a spectrometer are also included;

[0015] The output end of the coupling structure extending from the optical force microcavity is connected to the input end of the beam splitter, the first output end of the beam splitter is connected to the photodetector, the photodetector is connected to the oscilloscope, and the second output end of the beam splitter is connected to the spectrometer;

[0016] The oscilloscope is used to output the time domain waveform detected by the photodetector, and the spectrometer is used to measure the output spectrum of the second output end of the beam splitter.

[0017] Optionally, the pump source includes a wavelength-tunable laser.

[0018] Optionally, the pump source includes a laser with a fixed wavelength.

[0019] Optionally, the optical force microcavity includes a whispering gallery mode optical force microcavity, and the optical mode is coupled with the mechanical mode of the optical force microcavity itself.

[0020] Optionally, the optical force microcavity includes a standing wave mode optical force microcavity, and a micro-nano structure, a membrane structure, a photonic crystal, a phononic crystal or a vibrating atomic cloud is arranged in the standing wave mode optical force microcavity;

[0021] The optical mode is coupled with the mechanical mode of the object in the optical force microcavity.

[0022] Optionally, the repetition frequency of the optical frequency comb is determined by the mechanical mode resonance frequency, and the mechanical mode resonance frequency is in the kHz, MHz or GHz order.

[0023] Optionally, the coupling structure and the optical force microcavity are integrated on the same base substrate.

[0024] In a second aspect, an embodiment of the present invention further provides an optical frequency comb generation method, which is performed using any of the above-mentioned optical frequency comb generation systems, comprising:

[0025] The pump source outputs pump light, and the pump light is coupled into the optical force microcavity through the coupling structure;

[0026] Adjusting the pump light and the coupling structure so that the pump light and the optical force microcavity are in a large blue detuned state, and the coupling structure and the optical force microcavity are in an over-coupled state, so that the optical force microcavity outputs an optical frequency comb;

[0027] Among them, the pump light excites an optical mode in the photomechanical microcavity; the optical mode is coupled with the mechanical mode to generate a dynamic reaction; the dynamic reaction drives the mechanical mode to generate optical sidebands and output an optical frequency comb; the large blue detuned state is that the difference between the pump light frequency and the optical mode resonance frequency is greater than ten times the mechanical mode resonance frequency, and the overcoupled state is that the optical mode loss rate is at the same order of magnitude as the mechanical mode resonance frequency.

[0028] The optical frequency comb generation system provided by the embodiment of the present invention includes a pump source, a coupling structure and an optical force microcavity; the pump source is used to provide pump light, and the pump light is coupled into the coupling structure; the coupling structure is used to couple the pump light into the optical force microcavity; the optical force microcavity is integrated on a substrate, and the optical force microcavity includes an optical mode and a mechanical mode; the pump light excites the optical mode in the optical force microcavity; the optical mode is coupled with the mechanical mode to generate a dynamic reaction; the dynamic reaction drives the mechanical mode to generate an optical sideband and output an optical frequency comb; wherein the pump light and the optical force microcavity are in a large blue detuned state, and the coupling structure and the optical force microcavity are in an over-coupled state, the large blue detuned state is that the difference between the pump light frequency and the optical mode resonance frequency is greater than ten times the mechanical mode resonance frequency, and the over-coupled state is that the optical mode loss rate and the mechanical mode resonance frequency are at the same order of magnitude. A pump light is provided by a pump source, and the pump light is coupled into an optical force microcavity through a coupling structure. The optical force microcavity includes an optical mode and a mechanical mode. When the pump light is transmitted in the optical force microcavity, it is coupled with the mechanical mode. When the pump light and the optical force microcavity are in a large blue detuned state, and the coupling structure and the optical force microcavity are in an over-coupled state, the optical mode and the mechanical mode are coupled to produce a dynamic reaction; the dynamic reaction drives the mechanical mode to produce an optical sideband, thereby outputting an optical frequency comb; chip integration can be achieved by utilizing an optical force microcavity integrated on a substrate; the large blue detuned state and the over-coupled state can improve the bandwidth, efficiency and spectral flatness of the optical frequency comb, and can suppress the optical force chaos phenomenon; the optical frequency comb generation system provided in this embodiment can generate a high-performance, wide-bandwidth, low-repetition-rate (<GHz) optical frequency comb that can be used for chip integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic structural diagram of an optical frequency comb generation system provided by an embodiment of the present invention;

[0030] Figure 2is a schematic structural diagram of another optical frequency comb generation system provided by an embodiment of the present invention;

[0031] Figure 3 is a schematic structural diagram of another optical frequency comb generation system provided by an embodiment of the present invention;

[0032] Figures 4 to 9 They are schematic diagrams of the structure of an optical force microcavity provided by an embodiment of the present invention;

[0033] Fig.10 is a flow chart of a method for generating an optical frequency comb provided by an embodiment of the present invention;

[0034] Fig.11 is a schematic diagram of an oscilloscope waveform of an optical frequency comb generated by an embodiment of the present invention;

[0035] Fig.12 is a schematic diagram of a spectrum of an optical frequency comb generated by an embodiment of the present invention;

[0036] Fig.13 Schematic diagram of the relationship between the number of comb teeth and pump power in an embodiment of the present invention;

[0037] Fig.14 is a schematic diagram of an oscilloscope waveform of another optical frequency comb generated by an embodiment of the present invention;

[0038] Fig.15 is a schematic diagram of a spectrum of another optical frequency comb generated by an embodiment of the present invention;

[0039] Fig.16 It is a schematic diagram of the principle of an optical frequency comb generation system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0040] 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.

[0041] 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.

[0042] Figure 1 FIG. 1 is a schematic diagram of the structure of an optical frequency comb generation system provided by an embodiment of the present invention. Figure 1 The optical frequency comb generation system provided in this embodiment includes a pump source 10, a coupling structure 20 and an optical force microcavity 30; the pump source 10 is used to provide pump light, and the pump light is coupled into the coupling structure 20; the coupling structure 20 is used to couple the pump light into the optical force microcavity 30; the optical force microcavity 30 is integrated on a substrate, and the optical force microcavity 30 includes an optical mode and a mechanical mode; the pump light excites the optical mode in the optical force microcavity 30; the optical mode is coupled with the mechanical mode to generate a dynamic reaction; the dynamic reaction drives the mechanical mode to generate an optical sideband and output an optical frequency comb; wherein, the pump light and the optical force microcavity 30 are in a large blue detuned state, and the coupling structure 20 and the optical force microcavity 30 are in an over-coupled state, the large blue detuned state is that the difference between the pump light frequency and the optical mode resonance frequency is greater than ten times the mechanical mode resonance frequency, and the over-coupled state is that the optical mode loss rate and the mechanical mode resonance frequency are at the same order of magnitude.

[0043] Wherein, the pump source 10 is used to generate pump light for exciting the optical frequency comb. In a certain embodiment, the pump source 10 optionally includes a wavelength-tunable laser, such as a wavelength-tunable fiber laser, a wavelength-tunable semiconductor laser, etc., and the pump light is adjusted to a pump frequency that is detuned from the large blue state of the optical force microcavity 30 by adjusting the output wavelength of the pump light. In another embodiment, the pump source 10 optionally includes a laser with a fixed wavelength, and the pump source 10 outputs a pump light of a fixed frequency, and utilizes the nonlinear effect of the optical force microcavity 30 (such as thermo-optical nonlinearity, the thermal effect generated by the optical force microcavity causes a nonlinear frequency shift in the resonant frequency of the optical mode, which is equivalent to a change in the pump light frequency) so that the large blue detuned state condition is directly achieved when the pump light wavelength remains unchanged. In specific implementation, the method of selecting the pump source 10 can be selected according to actual conditions, and the embodiment of the present invention does not limit this. The coupling structure 20 is used to receive the pump light emitted by the pump source 10 and couple the pump light into the optical microcavity 30. In specific implementation, the coupling structure 20 may include a tapered optical fiber, a micro-nano optical fiber or other optical waveguides. Schematically, Figure 1 The coupling structure 20 shown in the figure is an optical fiber including a conical structure. The pump light generates an evanescent field in the conical structure to achieve coupling with the optical force microcavity 30. The coupling efficiency can be adjusted by adjusting the distance between the conical structure and the optical force microcavity 30. The conical structure can be obtained by melting and tapering the optical fiber. The optical fiber taper coupling method has the advantages of high coupling efficiency, strong controllability and convenient adjustment. During specific implementation, the type of coupling structure 20 can be selected according to actual experimental conditions, and the embodiment of the present invention is not limited thereto.

[0044] The optical microcavity 30 is a monolithically integrated optical microcavity with a high optical mode quality factor and a mechanical mode quality factor. It can be understood that in order to make the pump light in an over-coupled state, the total optical mode loss rate in the optical microcavity 30 needs to be equivalent to the mechanical mode resonance frequency (maintained within an order of magnitude), and the unit is Hz, and the total loss rate is obtained by adding the intrinsic loss rate to the coupling loss rate. The intrinsic loss rate is fixed after the microcavity is selected, so the total loss rate can only be adjusted by adjusting the coupling loss rate. The over-coupled state means that because the optical microcavity quality factor is very high and the intrinsic loss rate is very small, the efficiency of the optical frequency comb generation can be greatly improved. At this time, if the total optical mode loss rate is to be equivalent to the mechanical mode resonance frequency, the loss rate caused by the coupling must be increased. At this time, the coupling loss rate is much greater than the cavity intrinsic loss rate, which is the so-called over-coupled state. In this state, the bandwidth, efficiency and spectral flatness of the optical frequency comb can be improved, and the optical force chaos phenomenon can also be effectively suppressed. The large blue detuned state requires that the pump detuning amount is at least ten times greater than the mechanical mode resonance frequency. The pump detuning amount is the difference between the pump light frequency and the mechanical mode resonance frequency. The pump detuning amount determines the spectral width of the optical frequency comb. The larger the pump detuning amount, the wider the spectral width. In specific implementation, it is often greater than thirty times the mechanical mode resonance frequency. By adjusting the pump frequency to the appropriate large blue detuned pump, the amplitude of the mechanical mode of the photomechanical microcavity 30 can be amplified and optimally pumped, thereby generating an optical frequency comb with wide bandwidth, high efficiency, spectrally flatness and strong coherence.

[0045] In addition, the bandwidth of the optical frequency comb can be expanded by increasing the pump power, and the center frequency of the optical frequency comb can be adjusted by adjusting the pump light frequency. Among them, by selecting the optical modes of the optical force microcavity with different resonance frequencies, optical frequency combs of different wavelengths can be realized, such as but not limited to visible light, infrared, and ultraviolet optical frequency combs. Optionally, the repetition frequency of the optical frequency comb is determined by the mechanical mode resonance frequency, which is in the kHz, MHz or GHz order. By selecting optical force microcavities with different optical modes, optical frequency combs of different optical bands can be realized, and by selecting optical force microcavities with different mechanical modes, optical frequency combs of different repetition frequencies can be realized.

[0046] The technical solution of this embodiment provides pump light through a pump source, and couples the pump light into an optical force microcavity through a coupling structure. The optical force microcavity includes an optical mode and a mechanical mode. The pump light is coupled with the mechanical mode when transmitted in the optical force microcavity. When the pump light and the optical force microcavity are in a large blue detuned state, and the coupling structure and the optical force microcavity are in an over-coupled state, the optical mode and the mechanical mode are coupled to produce a dynamic reaction; the dynamic reaction drives the mechanical mode to produce an optical sideband, thereby outputting an optical frequency comb; chip integration can be achieved by utilizing an optical force microcavity integrated on a substrate; the large blue detuned state and the over-coupled state can improve the bandwidth, efficiency and spectral flatness of the optical frequency comb, and can suppress the optical force chaos phenomenon; the optical frequency comb generation system provided in this embodiment can generate high-performance, wide-bandwidth, low-repetition-rate (<GHz) optical frequency combs that can be used for chip integration.

[0047] Based on the above technical solutions, Figure 2 FIG. 2 is a schematic diagram of the structure of another optical frequency comb generation system provided by an embodiment of the present invention. Figure 2 Optionally, the optical frequency comb generation system provided in this embodiment further includes a polarization controller 40, and the polarization controller 40 is located between the pump source 10 and the coupling structure 20, and the polarization controller 40 is used to adjust the polarization direction of the pump light.

[0048] Exemplarily, in a specific implementation, the coupling structure 20 includes an optical fiber, and the polarization direction of the pump light is adjusted by adjusting the polarization controller 40 to be in different states, thereby adjusting the coupling efficiency between the pump light and the optical force microcavity 30. The polarization controller 40 can be a three-ring or embedded polarization controller, which is not limited to the embodiments of the present invention.

[0049] Figure 3 FIG. 2 is a schematic diagram of the structure of another optical frequency comb generation system provided by an embodiment of the present invention. Figure 3 Optionally, the optical frequency comb generation system provided in this embodiment further includes a beam splitter 50, a photodetector 60, an oscilloscope 70 and a spectrometer 80; the output end of the coupling structure 20 extending from the optical force microcavity 30 is connected to the input end of the beam splitter 50, the first output end of the beam splitter 50 is connected to the photodetector 60, the photodetector 60 is connected to the oscilloscope 70, and the second output end of the beam splitter 50 is connected to the spectrometer 80; the oscilloscope 70 is used to output the time domain waveform detected by the photodetector 60, and the spectrometer 80 is used to measure the output spectrum of the second output end of the beam splitter 50.

[0050] It is understandable that in order to verify whether the optical frequency comb generation system provided by the embodiment of the present invention generates an optical frequency comb, a test is required. By observing the time domain waveform of the oscilloscope 70 and the spectrum measured by the spectrometer 80, it can be determined whether an optical frequency comb is generated. In a specific implementation, the beam splitter 50 can use a fiber coupler with a splitting ratio of 90:10 (any ratio is acceptable, not limited here) between the first output end and the second output end. In other embodiments, optical amplifiers, filters, polarization controllers and other structures can also be set at the output end of the pump source 10, and they can be selected according to actual conditions in a specific implementation.

[0051] Optionally, the optical force microcavity 30 includes a whispering gallery mode optical force microcavity, and the optical mode is coupled with the mechanical mode of the optical force microcavity itself. Optionally, the optical force microcavity 30 includes a standing wave mode optical force microcavity, and a micro-nano structure, a membrane structure, a photonic crystal, a phononic crystal or a vibrating atomic cloud is arranged in the standing wave mode optical force microcavity; the optical mode is coupled with the mechanical mode of the object in the optical force microcavity.

[0052] For example, Figures 4 to 9 The following are schematic diagrams of the structure of a light force microcavity provided by an embodiment of the present invention. Figures 4 to 9 , the shaded part is the light field distribution, the black line is the vibration contour of the cavity boundary, and the optical microcavity can be a microring core cavity, a microsphere cavity, or a microdisk cavity in the whispering gallery mode ( Figure 4 ), or it can be an optical microcavity in a standing wave mode, where Figure 5 Shown is a standing wave mode cantilever mirror. Figure 6 It is a membrane structure placed inside the cantilever mirror. Figure 7 is the localized mode in the photonic crystal / phononic crystal, Figure 8 Place a cloud of trapped / vibrating atoms or other suspended objects in the cavity. Fig. 9 A vibrating capacitor is coupled to the microwave field.

[0053] Optionally, the coupling structure 20 and the optical force microcavity 30 are integrated on the same substrate. In a specific implementation, the coupling structure 20 can be a structure such as a micro-nano optical fiber that can be integrated on a substrate. By integrating the coupling structure 20 and the optical force microcavity 30 on the same substrate, the integration of the optical frequency comb generation system can be further improved.

[0054] Fig.10 FIG. 1 is a flow chart of an optical frequency comb generation method provided by an embodiment of the present invention. The method can be performed by any optical frequency comb generation system provided by the above embodiments, and specifically includes the following steps:

[0055] Step S110: The pump source outputs pump light, and the pump light is coupled into the optical force microcavity through the coupling structure.

[0056] The pump source may include a wavelength-tunable laser or a fixed-wavelength laser, and the coupling structure may include a tapered optical fiber, a micro-nano optical fiber or other optical waveguides, etc., which may be flexibly selected according to actual conditions during implementation.

[0057] Step S120, adjust the pump light and the coupling structure so that the pump light and the optical force microcavity are in a large blue detuned state, and the coupling structure and the optical force microcavity are in an over-coupled state, so that the optical force microcavity outputs an optical frequency comb.

[0058] Among them, the pump light excites the optical mode in the photomechanical microcavity; the optical mode is coupled with the mechanical mode to produce a dynamic reaction; the dynamic reaction drives the mechanical mode to produce optical sidebands and output an optical frequency comb; the large blue detuned state is that the difference between the pump light frequency and the optical mode resonance frequency is greater than ten times the mechanical mode resonance frequency, and the overcoupled state is that the optical mode loss rate is at the same order of magnitude as the mechanical mode resonance frequency.

[0059] The technical solution of this embodiment provides pump light through a pump source, and couples the pump light into an optical force microcavity through a coupling structure. The optical force microcavity includes an optical mode and a mechanical mode. The pump light is coupled with the mechanical mode when transmitted in the optical force microcavity. When the pump light and the optical force microcavity are in a large blue detuned state, and the coupling structure and the optical force microcavity are in an over-coupled state, the optical mode and the mechanical mode are coupled to produce a dynamic reaction; the dynamic reaction drives the mechanical mode to produce an optical sideband, thereby outputting an optical frequency comb; chip integration can be achieved by utilizing an optical force microcavity integrated on a substrate; the large blue detuned state and the over-coupled state can improve the bandwidth, efficiency and spectral flatness of the optical frequency comb, and can suppress the optical force chaos phenomenon; the optical frequency comb generation system provided in this embodiment can generate high-performance, wide-bandwidth, low-repetition-rate (<GHz) optical frequency combs that can be used for chip integration.

[0060] Specifically, Figure 3 Taking the structure of the optical frequency comb generation system shown in the figure as an example, in a certain embodiment, the pump source 10 adopts a wavelength tunable laser of about 1550nm, the coupling structure 20 adopts an optical fiber with a tapered structure, the optical fiber is bendable and has good compatibility and integration characteristics with existing optical fiber output and input port devices, and the optical force microcavity 30 adopts a silicon oxide material on-chip whispering gallery mode microring core cavity structure, and the substrate adopts a silicon structure. Here, the silicon oxide microring core cavity has the advantages of low cost, ultra-high optical and mechanical mode quality factors, and chip integration. The silicon oxide microring core cavity used has a diameter of 50μm and an optical mode quality factor of >10 7 , mechanical mode quality factor>3000, mechanical mode resonance frequency 26.5MHz, optical coupling coefficient 20GHz / nm, Fig.11 FIG. 1 is a schematic diagram of an oscilloscope waveform of an optical frequency comb generated by an embodiment of the present invention. Fig.12 The figure shows a spectrum schematic diagram of an optical frequency comb generated by an embodiment of the present invention, where the frequency interval of the comb teeth is the mechanical mode resonance frequency of 26.5 MHz. Fig.13 FIG. 1 is a schematic diagram showing the relationship between the number of comb teeth and pump power in an embodiment of the present invention, referring to FIG. Fig.13 By gradually increasing the pump power and adjusting the pump source 10 to a suitable large blue detuning frequency, it can be obtained that the number of optical frequency comb teeth (bandwidth) increases with increasing power.

[0061] In another embodiment, the optical force microcavity 30 is a silicon oxide microsphere cavity with a diameter of 30 μm and an optical mode quality factor of >10. 7 , the mechanical mode quality factor is >3000, the mechanical mode resonance frequency is 136.5MHz, and the photomechanical coupling coefficient is 20GHz / nm. Fig.14 FIG. 4 is a schematic diagram of an oscilloscope waveform of another optical frequency comb generated by an embodiment of the present invention. Fig.15 The figure shows a schematic diagram of the spectrum of another optical frequency comb generated by an embodiment of the present invention, where the frequency interval of the comb teeth is the mechanical mode resonance frequency of 136.5 MHz.

[0062] In other embodiments, the optical force microcavity may also be a standing wave mode optical force microcavity. Fig.16 The figure shows a schematic diagram of the principle of an optical frequency comb generation system provided by an embodiment of the present invention, in which one of the cavity mirrors is a movable cavity mirror, and the cavity mirror is driven to move by the optical mode light pressure in the optical force microcavity, so that the optical mode in the standing wave mode optical force microcavity is coupled with the mechanical mode of the cavity mirror, and an optical frequency comb is generated through dynamic reaction. Overcoupling is achieved by designing the coupling structure of the optical waveguide and the standing wave mode optical microcavity, and the pump source pumps the standing wave mode optical force microcavity to generate optical sidebands. The pump light source is continuously adjusted to a suitable large blue detuned pump frequency to widen a small amount of optical sidebands to a wide-bandwidth optical frequency comb, and the spectrum is flattened. The frequency interval of the teeth of the generated optical frequency comb is the resonance frequency of the cavity mirror mechanical mode.

[0063] 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. An optical frequency comb generation system, characterized in that: It includes a pump source, a coupling structure and a photomechanical microcavity; The pump source is used to provide pump light, and the pump light is coupled into the coupling structure; The coupling structure is used to couple the pump light into the optical force microcavity; The optical force microcavity is integrated on a base substrate, and the optical force microcavity includes an optical mode and a mechanical mode; The pump light excites the optical mode in the optical force microcavity; The optical mode is coupled with the mechanical mode to generate a dynamic reaction; The dynamic reaction drives the mechanical mode to generate optical sidebands and output an optical frequency comb; Among them, the pump light and the optical force microcavity are in a large blue detuned state, and the coupling structure and the optical force microcavity are in an over-coupled state. The large blue detuned state means that the difference between the pump light frequency and the optical mode resonance frequency is greater than ten times the mechanical mode resonance frequency, and the over-coupled state means that the optical mode loss rate is at the same order of magnitude as the mechanical mode resonance frequency.

2. The optical frequency comb generation system according to claim 1, characterized in that: It also includes a polarization controller, which is located between the pump source and the coupling structure, and is used to adjust the polarization direction of the pump light.

3. The optical frequency comb generation system according to claim 1, characterized in that: It also includes a beam splitter, a photodetector, an oscilloscope, and a spectrometer; The output end of the coupling structure extending from the optical force microcavity is connected to the input end of the beam splitter, the first output end of the beam splitter is connected to the photodetector, the photodetector is connected to the oscilloscope, and the second output end of the beam splitter is connected to the spectrometer; The oscilloscope is used to output the time domain waveform detected by the photodetector, and the spectrometer is used to measure the output spectrum of the second output end of the beam splitter.

4. The optical frequency comb generation system according to any one of claims 1 to 3, characterized in that: The pump source includes a wavelength-tunable laser.

5. The optical frequency comb generation system according to any one of claims 1 to 3, characterized in that: The pump source includes a fixed wavelength laser.

6. The optical frequency comb generation system according to any one of claims 1 to 3, characterized in that: The optical force microcavity includes a whispering gallery mode optical force microcavity, and the optical mode is coupled with the mechanical mode of the optical force microcavity itself.

7. The optical frequency comb generation system according to any one of claims 1 to 3, characterized in that: The optical force microcavity includes a standing wave mode optical force microcavity, in which a micro-nano structure, a membrane structure, a photonic crystal, a phononic crystal or a vibrating atomic cloud is arranged; The optical mode is coupled with the mechanical mode of the object in the optical force microcavity.

8. The optical frequency comb generation system according to any one of claims 1 to 3, characterized in that: The repetition frequency of the optical frequency comb is determined by the mechanical mode resonance frequency, which is in the kHz, MHz or GHz range.

9. The optical frequency comb generation system according to any one of claims 1 to 3, characterized in that: The coupling structure and the optical force microcavity are integrated on the same base substrate.

10. A method for generating an optical frequency comb, characterized in that: The method is performed by using the optical frequency comb generation system according to any one of claims 1 to 9, comprising: The pump source outputs pump light, and the pump light is coupled into the optical force microcavity through the coupling structure; Adjusting the pump light and the coupling structure so that the pump light and the optical force microcavity are in a large blue detuned state, and the coupling structure and the optical force microcavity are in an over-coupled state, so that the optical force microcavity outputs an optical frequency comb; Among them, the pump light excites an optical mode in the photomechanical microcavity; the optical mode is coupled with the mechanical mode to generate a dynamic reaction; the dynamic reaction drives the mechanical mode to generate optical sidebands and output an optical frequency comb; the large blue detuned state is that the difference between the pump light frequency and the optical mode resonance frequency is greater than ten times the mechanical mode resonance frequency, and the overcoupled state is that the optical mode loss rate is at the same order of magnitude as the mechanical mode resonance frequency.

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