Optical cavity locking system and method

Abstract

The invention provides an optical cavity locking system and method. The system comprises a laser assembly, a mode regulation and control assembly, an optical resonant cavity assembly, a detection assembly and a servo controller. The laser assembly is used for generating incident laser and adjusting parameters of the incident laser; the mode regulation and control assembly is used for splitting incident laser into first laser and second laser; the optical resonant cavity assembly is used for generating a transmission peak signal through the first laser and generating a nonlinear process through the second laser to obtain a first optical signal and a second optical signal; the detection assembly is used for converting the first optical signal into an intensity signal, performing difference frequency operation on the intensity signal and the microwave signal to generate a difference frequency signal and amplifying the difference frequency signal to obtain an error signal; the servo controller is used for receiving an error signal generated by the detection assembly; and generating a feedback signal based on the error signal and transmitting the feedback signal to a feedback actuator of the laser assembly, so as to solve the problem that the locking between the high-power laser and the high-quality factor optical resonant cavity is difficult at present.

Description

Technical Field

[0001] The present application relates to the field of optical photoelectric modulation technology, and in particular to an optical lock cavity system and method. Background Art

[0002] A series of high-power applications based on optical resonators are key research directions in the field of optical resonators. The high reflectivity of optical resonators allows various nonlinear optical effects to be observed when high-power lasers propagate in the cavity, including but not limited to: the generation and compression of pulsed lasers, optical parametric oscillation, optical parametric amplification, etc. In high-power application scenarios, it is necessary to improve the frequency stability of lasers through cavity locking technology, which is of great significance for further exploration of nonlinear optical effects, future development of new optical devices, and advancement of cutting-edge scientific and technological progress.

[0003] In an optical resonant cavity, high-power input signals can cause thermal effects and nonlinear optical effects, including thermal drift of the optical resonant cavity length, thermo-optical effects, self-modulation effects, etc., which lead to unstable mode spacing and laser waveform distortion.

[0004] If the traditional cavity lock technology is used to directly lock the optical resonant cavity in high-power scenarios, the peak signal and error signal will be distorted, making it difficult for the feedback system to accurately identify and track the frequency and phase information in the optical cavity, which will lead to locking failure or large frequency fluctuations. These effects from the nonlinear effects in the cavity need to be overcome by adjusting the signal processing algorithm or introducing additional compensation measures. The feedback signal needs to be adjusted dynamically in real time to offset the influence of external interference and internal effects, but this solution requires complex equipment and systems and is difficult to implement. Summary of the invention

[0005] The present application provides an optical cavity locking system and method to solve the technical problem of the difficulty in locking between the existing high-power laser and the high-quality factor optical resonant cavity.

[0006] In a first aspect, the present application provides an optical cavity lock system, comprising: a laser component, a mode control component, an optical resonant cavity component, a detection component and a servo controller;

[0007] The laser assembly is used to generate incident laser light and adjust parameters of the incident laser light;

[0008] The mode control component is used to split the incident laser beam into a first laser beam and a second laser beam, and perform modulation, frequency shifting, and optical amplification operations on the first laser beam and the second laser beam, so that the cavity power of the first laser beam is less than the cavity power of the second laser beam;

[0009] The optical resonant cavity component is used to generate a transmission peak signal through the first laser, and to generate a nonlinear process through the second laser to obtain a first optical signal and a second optical signal;

[0010] The detection component is used to convert the first optical signal into an intensity signal, perform a difference frequency operation on the intensity signal and the microwave signal from the radio frequency signal generator to generate a difference frequency signal and amplify the difference frequency signal to obtain an error signal;

[0011] The servo controller is used to receive the error signal generated by the detection component; based on the error signal, generate a feedback signal and transmit it to the feedback actuator of the laser component, so that the deviation value of the incident laser frequency generated by the laser component relative to the resonance frequency of the optical resonant cavity component is within a set range.

[0012] In some embodiments, the laser assembly comprises:

[0013] A laser, wherein the laser is used to generate incident laser light;

[0014] A feedback actuator is arranged in the same optical path as the laser and is used to adjust the parameters of the incident laser.

[0015] In some embodiments, the mode control component includes:

[0016] A first mode controller, which is arranged in the same optical path as the laser assembly and is used to adjust the ratio of the first laser and the second laser entering the cavity;

[0017] a first beam splitter, which is arranged in the same optical path as the first mode controller and is used to split the incident laser into the first laser and the second laser;

[0018] A first electro-optic modulator, which is arranged in the same optical path as the first beam splitter and is used to perform a phase modulation operation on the first laser;

[0019] First high-power component: the first high-power component is arranged in the same optical path as the first beam splitter, and is used to perform modulation, frequency shifting, and optical amplification operations on the second laser;

[0020] A first beam combiner is provided in the same optical path as the first high-power component and the first electro-optic modulator, and is used for combining the first laser and the second laser.

[0021] In some embodiments, the mode control component includes:

[0022] Second high-power component: The second high-power component is arranged in the same optical path as the laser component, and is used for the laser to perform modulation and optical amplification operations;

[0023] A second mode controller, which is arranged in the same optical path as the second high-power component and is used to adjust the ratio of the first laser and the second laser entering the cavity;

[0024] a second beam splitter, which is arranged in the same optical path as the second mode controller and is used to split the incident laser into the first laser and the second laser;

[0025] A second electro-optic modulator, which is arranged in the same optical path as the second beam splitter and is used to perform a phase modulation operation on the first laser;

[0026] The second beam combiner is respectively arranged in the same optical path as the second beam splitter and the second electro-optic modulator, and is used for combining the first laser and the second laser.

[0027] In some embodiments, the optical resonant cavity group includes:

[0028] An optical resonant cavity, the optical resonant cavity and the mode control component are arranged in the same optical path, and are used to generate a transmission peak signal through the first laser, and to transmit the second laser and generate a nonlinear process;

[0029] A third beam splitter is arranged in the same optical path as the optical resonant cavity and the detection component, and is used to split the light beam transmitted through the optical resonant cavity to obtain a first light signal and a second light signal.

[0030] In some embodiments, the detection component includes: a photodetector, a mixer, a radio frequency signal generator, a bandpass filter, and a low noise amplifier;

[0031] The photoelectric detector is arranged in the same optical path as the third beam splitter, and is used to convert the first optical signal into an intensity signal;

[0032] The mixer is communicatively connected with the photoelectric detector, and is used for performing difference frequency operation on the intensity signal and the microwave signal from the radio frequency signal generator to generate a difference frequency signal and output the difference frequency signal;

[0033] The radio frequency signal generator is in communication with the mode control component and the mixer, and is used to transmit a microwave signal of a set frequency to the electro-optical modulator and the mixer;

[0034] The bandpass filter is communicatively connected to the mixer and is used for filtering the difference frequency signal;

[0035] The low noise amplifier is communicatively connected to the band pass filter and is used for amplifying the difference frequency signal to obtain an error signal.

[0036] In some embodiments, the second optical signal can be applied after being emitted through the optical resonant cavity group; the applications include: laser radar, gas detection, and optical atomic clock.

[0037] The second aspect of the present application provides an optical lock cavity method, which is applied to an optical lock cavity system described in any one of the first aspects above, comprising:

[0038] The laser component and the mode control component are adjusted so that the cavity power of the first laser is less than the cavity power of the second laser, and the combined beam is transmitted through the optical resonant cavity component to generate a second light signal and a transmission peak signal, and then the transmission peak signal is converted into an intensity signal by a photodetector, and the frequency of the microwave signal is set according to the frequency of the intensity signal, and a difference frequency operation is performed on the intensity signal and the microwave signal by a mixer to obtain a difference frequency signal;

[0039] The difference frequency signal is filtered by a bandpass filter and then input into a low noise amplifier for frequency drift conversion to obtain an error signal;

[0040] Based on the error signal, a feedback signal is generated by a servo controller and transmitted to a feedback actuator of the laser assembly, so that the deviation value between the frequency of the incident laser generated by the laser assembly and the cavity resonance frequency is within a set range.

[0041] In some embodiments, the step of adjusting the laser component and the mode control component so that the cavity power of the first laser is less than the cavity power of the second laser, and combining the beams to generate the second light signal and the transmission peak signal through the optical resonant cavity component includes:

[0042] Adjusting the incident laser power generated by the laser assembly and the mode controller in the mode control assembly until the incident power of the first laser is less than the incident power of the second laser;

[0043] The high-power component in the mode control component is adjusted so that the second laser undergoes a nonlinear process in the resonant cavity component to obtain a second optical signal; the second optical signal can be applied, and the applications include: laser radar, gas detection, and optical atomic clock.

[0044] The present application provides an optical cavity lock system and method, the system comprising: a laser component, a mode control component, an optical resonant cavity component, a detection component and a servo controller; the laser component is used to generate an incident laser and adjust the parameters of the incident laser; the mode control component is used to split the incident laser into a first laser and a second laser, and perform modulation, frequency shifting, and optical amplification operations on the first laser and the second laser, so that the cavity power of the first laser is less than the cavity power of the second laser; the optical resonant cavity component is used to generate a transmission peak signal through the first laser, and to transmit the second laser and generate a nonlinear process to obtain a first optical signal and a second optical signal; the detection component is used to convert the first optical signal into an intensity signal, and the intensity signal is subjected to a difference frequency operation with a microwave signal from a radio frequency signal generator to generate a difference frequency signal and amplify to obtain an error signal; the servo controller is used to receive the error signal generated by the detection component; based on the error signal, a feedback signal is generated and transmitted to the feedback actuator of the laser component, so that the deviation value of the incident laser frequency generated by the laser component relative to the resonance frequency of the optical resonant cavity component is within a set range, so as to solve the locking problem of the reference cavity under high-power application through a single-cavity polarization multiplexing or wavelength division multiplexing mode, and use the polarization separation or wavelength division multiplexing characteristics of the optical resonant cavity to achieve relatively independent application of low-power signals and high-power signals, that is: the low-power signal is used to lock the optical resonant cavity, and the high-power signal is used for the occurrence of nonlinear processes in the cavity; without affecting the nonlinear process and high-power scene application, the laser frequency can be accurately locked, and the relative stability of the laser frequency can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0046] Figure 1 is a first schematic diagram of the optical lock cavity system in this application;

[0047] Figure 2 is a second schematic diagram of the optical lock cavity system in this application;

[0048] Figure 3 An optical lock cavity flow chart of an optical lock cavity system in one embodiment of the present application;

[0049] Figure 4 FIG. 4 is a flow chart of an optical lock cavity system according to another embodiment of the present application.

[0050] Description of reference numerals:

[0051] 1-laser assembly; 11-laser; 12-feedback actuator; 2-mode control assembly; 21-first mode controller; 22-first beam splitter; 23-first high-power assembly; 24-first electro-optic modulator; 25-first combiner; 26-second high-power assembly; 27-second mode controller; 28-second beam splitter; 29-second electro-optic modulator; 30-second combiner; 3-optical resonant cavity assembly; 31-optical resonant cavity; 32-third beam splitter; 4-detection assembly; 41-photodetector; 42-mixer; 43-RF signal generator; 44-bandpass filter; 45-low noise amplifier; 5-servo controller. DETAILED DESCRIPTION

[0052] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0053] Since it is difficult to lock a high-power laser with a high-quality factor optical resonant cavity in some technologies, in order to solve this technical problem, the present application provides an optical cavity locking system and method, which are described below:

[0054] For example, high-power cavity lock technology is a key research direction in the field of optical resonant cavities, which aims to solve the problem of stable locking of optical resonant cavities in high-power application scenarios. The high reflectivity of the optical resonant cavity allows various nonlinear optical effects to be observed when the high-power laser propagates in the cavity, including but not limited to: the generation and compression of pulsed lasers, optical parametric oscillation, optical parametric amplification and other processes. In an optical microcavity, a high-power input signal may cause thermal effects and optical nonlinear effects, including thermal drift of the optical resonant cavity length, thermo-optical effects, self-modulation effects, etc., resulting in unstable mode spacing and laser waveform distortion. In high-power application scenarios, improving system stability through cavity lock technology is of great significance for further exploration of nonlinear optical effects, future development of new optical devices and advancement of cutting-edge scientific and technological progress. Therefore, high-power cavity lock technology has broad development prospects in optical microcavity research and applications.

[0055] Locking an optical resonant cavity in a high-power scenario is relatively complicated because high power may introduce additional thermal effects and optical nonlinear effects, affecting the stability and accuracy of the locking. If traditional cavity locking technology is used to directly lock an optical resonant cavity in a high-power scenario, it will cause distortion of the peak signal and the error signal, making it difficult for the feedback system to accurately identify and track the frequency and phase information in the optical cavity, leading to locking failure or large frequency fluctuations. These influences from the nonlinear effects in the cavity need to be overcome by adjusting the signal processing algorithm or introducing additional compensation measures. The feedback signal needs to be adjusted dynamically in real time to offset the influence of external interference and internal effects, but this solution requires complex equipment and systems and is difficult to implement.

[0056] For example, PDH (Pound-Drever-Hall) technology is a widely used and powerful laser frequency stabilization method, which achieves frequency stabilization by locking to a stable optical cavity. The principle of PDH technology frequency stabilization is: lock the laser to be stabilized to the optical cavity, thereby achieving the transfer of the stability of the reference cavity to the stability of the laser frequency.

[0057] Depend on Figure 1 It can be seen that, in response to the above problems, the first aspect of the present application provides an optical cavity lock system, including: a laser component 1, a mode control component 2, an optical resonant cavity component 3, a detection component 4 and a servo controller 5; the laser component 1 is used to generate an incident laser and adjust the parameters of the incident laser; the parameters include but are not limited to: laser wavelength, laser power; the mode control component 2 is used to split the incident laser into a first laser and a second laser, and perform operations including but not limited to: modulation, frequency shift, and optical amplification on the first laser and the second laser, so that the cavity power of the first laser is less than the cavity power of the second laser; the optical resonant cavity component 3 is used to generate a transmission peak signal through the first laser, and transmit the second laser and cause a nonlinear process to obtain a first a light signal and a second light signal; the detection component 4 is used to convert the first light signal into an intensity signal, the intensity signal and the microwave signal from the radio frequency signal generator are subjected to a difference frequency operation to generate a difference frequency signal and amplify it to obtain an error signal; the error signal is used to reflect the deviation between the frequency of the incident laser and the resonant frequency of the optical resonant cavity component; the servo controller 5 is used to receive the error signal generated by the detection component 4; based on the error signal, a feedback signal is generated and transmitted to the feedback actuator 12 of the laser component 1, so that the deviation value of the incident laser frequency generated by the laser component 1 relative to the resonant frequency of the optical resonant cavity component 3 is within a set range; the feedback actuator 12 includes but is not limited to: piezoelectric ceramics, acousto-optic modulators.

[0058] The present application provides an optical locked cavity system, wherein an incident laser is generated by a laser component 1, and the incident laser is split into a first laser and a second laser by a mode control component 2. The first laser and the second laser are subjected to operations including but not limited to modulation, frequency shifting, and optical amplification, and then combined and incident on an optical resonant cavity component 3. After the second laser is reflected multiple times by an optical resonant cavity 31 of the optical resonant cavity component 3, multiple interferences are formed to enhance the intensity of optical signals of certain wavelengths, thereby generating a nonlinear process, in preparation for subsequent applications, such as the generation of an optical frequency comb, a frequency doubling process, etc.; the first laser generates a transmission peak signal in the optical resonant cavity component 3 in preparation for subsequent feedback; After the first laser and the second laser are combined, they are split into a first light signal and a second light signal through the output of the optical resonant cavity component 3. The second light signal can be used for subsequent applications. If an optical frequency comb is generated, it can be used for laser radar, gas detection, etc.; the first light signal is converted into photoelectric signals through the detection component 4 and then mixed with the microwave signal to generate an error signal; finally, a feedback signal is generated through the servo controller 5 and sent to the feedback actuator of the laser component 1 to suppress the frequency drift of the laser output by the laser component 1, so that the deviation value of the laser frequency output by the laser component 1 relative to the resonance frequency of the optical resonant cavity component 3 is within a set range.

[0059] In this embodiment, the laser assembly 1 includes but is not limited to: a laser 11, the laser 11 is used to generate incident laser light, and a feedback actuator 12, the feedback actuator 12 is arranged in the same optical path as the laser 11, and is used to adjust the parameters of the incident laser light.

[0060] Depend on Figure 3It can be known that the mode control component 2 includes but is not limited to: a first mode controller 21, which is arranged in the same optical path as the laser component 1, and is used to adjust the ratio of the power of the first laser and the second laser entering the cavity; the first mode controller 21 is an optical device that can change the polarization state or frequency of the light wave, and the power and characteristics of the laser can be controlled by adjusting the polarization state or frequency of the light wave. A first beam splitter 22, which is arranged in the same optical path as the first mode controller 21, and is used to split the incident laser into the first laser and the second laser. A first electro-optical modulator 24, which is arranged in the same optical path as the first beam splitter 22, is used to modulate the phase of the first laser; phase modulation is an important information transmission method, which transmits information by changing the phase of the laser. A first high-power component 23, which is arranged in the same optical path as the first beam splitter 22, is used to modulate, shift the frequency, amplify the light, etc., the second laser; the purpose of modulating the second laser is to modulate the intensity, frequency, phase or polarization state of the second laser to achieve subsequent nonlinear processes. The modulation method includes: (1) frequency modulation: using a modulator to change the frequency of the laser to achieve frequency conversion; (2) phase modulation: using a modulator to modulate the phase of the laser for beat frequency measurement; the ratio of the power of the first laser and the second laser entering the cavity needs to be relatively different, and the power of the second laser can be amplified by the first high-power component 23; the first beam combiner 25, the first beam combiner 25 is respectively arranged in the same optical path as the first high-power component 23 and the first electro-optical modulator 24, and is used to combine the first laser and the second laser. Exemplarily, in the present application, the first mode controller 21 is provided with two types, one is a polarization controller and the other is an optical switch; the first beam splitter 22 is provided with two types, one is a polarization beam splitter and the other is a wavelength division multiplexer; the first high-power component 23 is a fiber amplifier or an electro-optical frequency shifting device; the beam combiner 25 is provided with two types, one is a polarization beam combiner and the other is a common beam combiner.

[0061] Exemplarily, when the mode control component 2 includes: a polarization controller, i.e., the first mode controller 21, and a polarization beam splitter, i.e., the first beam splitter 22, the first high-power component 23 is a fiber amplifier, and the first beam combiner 25 is a polarization beam combiner, the matching beam splitter component is composed of a polarization controller and a polarization beam splitter, and the main function of the polarization beam splitter is to split the optical power while maintaining the original polarization state of the light. In this way, the horizontal polarized light and the vertical polarized light are separated, and the one with low power entering the cavity is used for locking, and the other is used for high-power application. Figure 3The flowchart shown is an optical lock cavity corresponding to each device in the above embodiment. The laser 11 adjusts the parameters of the incident laser through the feedback actuator 12, and is incident to the polarization controller. The polarization state of the light wave is changed by the polarization controller, and then it is incident to the polarization beam splitter, and the beam is split into a first laser with a smaller power, that is, horizontal polarized light, and a second laser with a larger power, that is, vertical polarized light. The horizontal polarized light passes through the first electro-optical modulator 24 to perform a phase modulation operation on the horizontal polarized light; the vertical polarized light passes through the optical fiber amplifier to perform an optical amplification operation on the vertical polarized light; the horizontal polarized light and the vertical polarized light after the above operation are incident to the polarization beam combiner for beam combining The combined light beam is incident on the optical resonant cavity component 3 and split into a first light signal and a second light signal. The horizontally polarized light generates a transmission peak signal in the optical resonant cavity component 3, and then is incident on the detection component 4 to generate an error signal which is fed back to the servo controller 5, so that the deviation value of the laser frequency output by the laser component 1 relative to the resonant frequency of the optical resonant cavity component 3 is within a set range, thereby realizing an optical cavity lock. After the vertically polarized light is reflected multiple times by the optical resonant cavity 31 of the optical resonant cavity component 3, multiple interferences are formed to enhance the intensity of light signals of certain wavelengths, thereby generating a nonlinear process, which prepares for subsequent applications, such as the generation of optical frequency combs and frequency doubling processes.

[0062] Exemplarily, when the mode control component 2 also includes: an optical switch and a wavelength division multiplexer, the optical switch mainly controls the paths of light of different wavelengths, thereby affecting their relative intensities, the high-power component is an electro-optical frequency shifting device, and the beam combiner is an ordinary beam combiner; wherein the matching beam splitter component is a wavelength division multiplexer; thereby achieving the purpose of using the un-shifted low-power light beam for locking, and the shifted high-power light beam for subsequent applications.

[0063] Depend on Figure 4 It can be seen that the mode control component 2 includes: a second high-power component 26: the second high-power component 26 is arranged in the same optical path as the laser component 1, and is used for the laser to modulate and amplify the light; a second mode controller 27, the second mode controller 27 is arranged in the same optical path as the second high-power component 26, and is used to adjust the ratio of the first laser and the second laser into the cavity power; a second beam splitter 28, the second beam splitter 28 is arranged in the same optical path as the second mode controller 27, and is used to split the incident laser into the first laser and the second laser. A second electro-optical modulator 29, the second electro-optical modulator 29 is arranged in the same optical path as the second beam splitter 28, and is used to perform phase modulation operation on the first laser; a second beam combiner 30, the second beam combiner 30 is arranged in the same optical path as the second beam splitter 28 and the second electro-optical modulator 29, and is used to combine the first laser and the second laser. It can be understood that the components in the mode control component 2 can also be arranged according to the above arrangement.

[0064] For example, when the mode control component 2 also includes: a polarization controller, i.e., a second mode controller 27, and a polarization beam splitter, i.e., a second beam splitter 28, the second high-power component 26 is a fiber amplifier, and the second beam combiner 30 is a polarization beam combiner, the matching beam splitter component is composed of a polarization controller and a polarization beam splitter, and the main function of the polarization beam splitter is to split the optical power while maintaining the original polarization state of the light. In this way, the horizontal polarized light and the vertical polarized light are separated, and the one with low power entering the cavity is used for locking, and the other is used for high-power applications. Figure 4 The flowchart shown is an optical lock cavity corresponding to each device in the above embodiment. The laser 11 adjusts the parameters of the incident laser through the feedback actuator 12, and is incident on the optical fiber amplifier to perform light amplification operation on the incident laser; then it is incident on the polarization controller, and the polarization state of the light wave is changed by the polarization controller, and then it is incident on the polarization beam splitter, and the beam is split into a first laser with a smaller power, that is, horizontal polarized light, and a second laser with a larger power, that is, vertical polarized light, wherein the horizontal polarized light passes through the first electro-optical modulator 24 to perform phase modulation operation on the horizontal polarized light; the horizontal polarized light and the vertical polarized light after the above operation are incident on the polarization beam combiner for beam combining The combined light beam is incident on the optical resonant cavity component 3 and split into a first light signal and a second light signal. The horizontally polarized light generates a transmission peak signal in the optical resonant cavity component 3, and then is incident on the detection component 4 to generate an error signal which is fed back to the servo controller 5, so that the deviation value of the laser frequency output by the laser component 1 relative to the resonant frequency of the optical resonant cavity component 3 is within a set range, thereby realizing an optical cavity lock. After the vertically polarized light is reflected multiple times by the optical resonant cavity 31 of the optical resonant cavity component 3, multiple interferences are formed to enhance the intensity of light signals of certain wavelengths, thereby generating a nonlinear process, which prepares for subsequent applications, such as the generation of optical frequency combs and frequency doubling processes.

[0065] Depend on Figure 2 It can be known that the optical resonant cavity component 3 includes but is not limited to: an optical resonant cavity 31, which is used as a reference cavity for frequency locking of low-power signals and a resonant cavity for the occurrence of nonlinear effects of high-power signals; the optical resonant cavity 31 is arranged in the same optical path as the beam combiner 25, and is used to generate a transmission peak signal through the first laser, and the optical resonant cavity 31 is used to transmit the second laser and undergo a nonlinear process; a second beam splitter 32, which is arranged in the same optical path as the optical resonant cavity 31 and the detection component 4, and is used to split the light beam transmitted by the optical resonant cavity into a first light signal and a second light signal.

[0066] Exemplarily, the optical resonant cavity in the present application includes but is not limited to a fiber FP resonant cavity (abbreviated as FP cavity), an air FP cavity, and an ultra-low expansion glass (ULE) FP cavity, wherein the fiber FP resonant cavity is the abbreviation of a Fabry-Pérot resonant cavity, which is composed of two parallel mirrors (or reflective surfaces) with high reflectivity, and light is reflected back and forth through the above two mirrors to form interference. At a specific wavelength, the multi-reflected light waves will form a peak signal, while the light waves of other wavelengths will cancel each other out.

[0067] Exemplarily, the second beam splitter 32 is provided in two types, one is a polarization beam splitter, and the other is a wavelength division multiplexer.

[0068] Depend on Figure 2 It can be known that the detection component 4 includes but is not limited to: a photodetector 41, a mixer 42, a radio frequency signal generator 43, a bandpass filter 44, and a low noise amplifier 45; the photodetector 41 is arranged in the same optical path as the second beam splitter 32, and is used to convert the first optical signal into an intensity signal; the mixer 42 is communicatively connected to the photodetector 41, and is used to perform a difference frequency operation on the intensity signal and the electrical signal from the radio frequency signal generator 43 and output a difference frequency signal; the radio frequency signal generator 43 is communicatively connected to the electro-optical modulator 24 and the mixer 42, and is used to transmit a local microwave signal of a set frequency to the electro-optical modulator 24 and the mixer 42; the bandpass filter 44 is communicatively connected to the mixer 42, and is used to filter the difference frequency signal; the low noise amplifier 45 is communicatively connected to the bandpass filter 44 and the servo controller 5, and is used to amplify the difference frequency signal to obtain an error signal. Among them, the mixer 42 can mix two signals of different frequencies (i.e., intensity signal and microwave signal) to generate a new frequency component, that is, to achieve frequency conversion; through the mixing process, the offset information of the laser frequency and the resonance frequency can be obtained, which is usually related to the phase, amplitude and other parameters of the signal, and is crucial for the subsequent error signal generation and correction.

[0069] Exemplarily, the specific process is as follows: the mixer 42 mixes the intensity signal in the electrical signal with the microwave signal; the mixer 42 outputs the sum and difference of the original signal frequency to generate a new frequency component; the mixed signal usually contains multiple frequency components, and it is necessary to remove unnecessary frequency components through a filter, and only retain specific frequency components containing frequency and resonance frequency offset information; the filtered signal is processed to extract the frequency and resonance frequency offset information; this includes steps such as demodulating and amplifying the signal to more accurately measure and analyze; based on the extracted frequency and resonance frequency offset information, the system can generate an error signal. This error signal is used to indicate the difference between the actual signal frequency and the expected frequency, and is the basis for subsequent correction and adjustment. The error signal is connected to the servo controller 5, and the servo controller 5 outputs a feedback signal to the feedback actuator of the laser assembly 1 to suppress the frequency drift of the laser emitted by the laser assembly 1, so as to reduce the frequency and resonance frequency offset and improve the stability and accuracy of the laser output frequency.

[0070] In this embodiment, after the second optical signal is emitted through the optical resonant cavity component 3, it is configured to: perform the application of the second optical signal; if an optical frequency comb is generated, the application can be: laser radar, gas detection, optical atomic clock, etc. The laser radar application includes: using pulsed laser to measure any length, accurately measuring the flight time difference between pulses, which depends on two moments, namely the start time when the pulse is emitted from the measurement system, and the end time when the emitted pulse is reflected by the object and received by the measurement system again, so as to obtain detailed information about the target object. The gas detection application includes: using an optical frequency comb to interact with gas molecules and then perform frequency domain analysis, which can simultaneously obtain a wide spectral coverage range and extremely high spectral resolution, and complete high-precision spectral measurement.

[0071] The present application provides an optical cavity lock system and method, the system comprising: a laser component 1, the laser component 1 is used to generate an incident laser and adjust the parameters of the laser; the mode control component 2 is used to split the incident laser into a first laser and a second laser, and perform operations including but not limited to modulation, frequency shift, optical amplification, etc. on the first laser and the second laser, so that the first laser cavity power is less than the second laser cavity power; the optical resonant cavity component 3 is used to generate a transmission peak signal through the first laser, transmit the second laser and generate a nonlinear process, and then split into a first light signal and a second light signal; the detection component 4 is used to convert the first light signal into an intensity signal, the intensity signal and the electrical signal from the radio frequency signal generator are subjected to a difference frequency operation and the difference frequency signal is output; the difference frequency signal is filtered and amplified to obtain an error signal difference signal; the servo controller 5 is used to receive the error signal sent by the detection component 4; based on the error signal, a feedback signal is generated and transmitted to the feedback actuator of the laser component 1 so that the deviation value of the laser output laser frequency relative to the resonance frequency of the optical resonant cavity component 3 is within a set range; so as to solve the locking problem of the reference cavity under high-power application through a single-cavity polarization multiplexing or wavelength division multiplexing mode, and use the polarization separation or wavelength division multiplexing characteristics of the optical resonant cavity to achieve relatively independent application of low-power signals and high-power signals, that is: the low-power signal is used to lock the optical resonant cavity, and the high-power signal is used for the occurrence of nonlinear processes in the cavity; without affecting the nonlinear process and high-power scene application, the laser frequency can be accurately locked, and the relative stability of the laser frequency can be further improved.

[0072] In a second aspect, the present application provides an optical cavity locking method, which is applied to an optical cavity locking system described in any of the above embodiments, comprising: adjusting a laser component and a mode control component so that the cavity power of a first laser is less than the cavity power of a second laser, combining the beams through an optical resonant cavity component to generate a second light signal and a transmission peak signal, and then converting the transmission peak signal into an intensity signal by a photodetector, and setting the frequency of a microwave signal according to the frequency of the intensity signal, and performing a difference frequency operation on the intensity signal and the microwave signal by a mixer to obtain a difference frequency signal; after filtering the difference frequency signal by a bandpass filter, the signal is input into a low noise amplifier for frequency drift conversion to obtain an error signal; based on the error signal, a feedback signal is generated by a servo controller and transmitted to a feedback actuator of the laser component, so that the deviation value between the frequency of the incident laser generated by the laser component and the cavity resonance frequency is within a set range. The effects of the above method embodiments can refer to the effects of the above system embodiments, which will not be described in detail here.

[0073] In this embodiment, the step of adjusting the laser component and the mode control component so that the cavity power of the first laser is less than the cavity power of the second laser, and the beam combination is transmitted through the optical resonant cavity component to generate the second optical signal and the transmission peak signal includes: adjusting the incident laser power generated by the laser component and the mode controller in the mode control component until the cavity power of the first laser is less than the cavity power of the second laser; adjusting the high-power component in the mode control component so that the first laser generates a transmission peak signal in the resonant cavity component, and the second laser undergoes a nonlinear process in the resonant cavity component to obtain a second optical signal; the second optical signal can be applied, and the applications include: laser radar, gas detection, and optical atomic clock. The effects of the above method embodiment can be referred to the effects of the above system embodiment, which will not be repeated here.

[0074] The above specific implementation methods further explain in detail the purpose, technical solutions and beneficial effects of the embodiments of the present application. It should be understood that the above are only specific implementation methods of the embodiments of the present application and are not used to limit the protection scope of the embodiments of the present application. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solutions of the embodiments of the present application should be included in the protection scope of the embodiments of the present application.

Claims

1. An optical lock cavity system, characterized in that: include: Laser components, mode control components, optical resonant cavity components, detection components and servo controllers; The laser assembly is used to generate incident laser light and adjust parameters of the incident laser light; The mode control component is used to split the incident laser beam into a first laser beam and a second laser beam, and perform modulation, frequency shifting, and optical amplification operations on the first laser beam and the second laser beam, so that the cavity power of the first laser beam is less than the cavity power of the second laser beam; The optical resonant cavity component is used to generate a transmission peak signal through the first laser, and to generate a nonlinear process through the second laser to obtain a first optical signal and a second optical signal; The detection component is used to convert the first optical signal into an intensity signal, perform a difference frequency operation on the intensity signal and the microwave signal from the radio frequency signal generator to generate a difference frequency signal and amplify the difference frequency signal to obtain an error signal; The servo controller is used to receive the error signal generated by the detection component; Based on the error signal, a feedback signal is generated and transmitted to a feedback actuator of the laser assembly, so that the deviation value of the incident laser frequency generated by the laser assembly relative to the resonant frequency of the optical resonant cavity assembly is within a set range.

2. An optical lock cavity system according to claim 1, characterized in that: The laser assembly comprises: A laser, wherein the laser is used to generate incident laser light; A feedback actuator is arranged in the same optical path as the laser and is used to adjust the parameters of the incident laser.

3. The optical lock cavity system according to claim 1, characterized in that: The mode control component includes: A first mode controller, which is arranged in the same optical path as the laser assembly and is used to adjust the ratio of the first laser and the second laser entering the cavity; a first beam splitter, which is arranged in the same optical path as the first mode controller and is used to split the incident laser into the first laser and the second laser; A first electro-optic modulator, which is arranged in the same optical path as the first beam splitter and is used to perform a phase modulation operation on the first laser; First high-power component: the first high-power component is arranged in the same optical path as the first beam splitter, and is used to perform modulation, frequency shifting, and optical amplification operations on the second laser; A first beam combiner is provided in the same optical path as the first high-power component and the first electro-optic modulator, and is used for combining the first laser and the second laser.

4. The optical lock cavity system according to claim 1, characterized in that: The mode control component includes: Second high-power component: The second high-power component is arranged in the same optical path as the laser component, and is used for the laser to perform modulation and optical amplification operations; A second mode controller, which is arranged in the same optical path as the second high-power component and is used to adjust the ratio of the first laser and the second laser entering the cavity; a second beam splitter, which is arranged in the same optical path as the second mode controller and is used to split the incident laser into the first laser and the second laser; A second electro-optic modulator, which is arranged in the same optical path as the second beam splitter and is used to perform a phase modulation operation on the first laser; The second beam combiner is respectively arranged in the same optical path as the second beam splitter and the second electro-optic modulator, and is used for combining the first laser and the second laser.

5. The optical lock cavity system according to claim 1, characterized in that: The optical resonant cavity group comprises: An optical resonant cavity, the optical resonant cavity and the mode control component are arranged in the same optical path, and are used to generate a transmission peak signal through the first laser, and to transmit the second laser and generate a nonlinear process; A third beam splitter is arranged in the same optical path as the optical resonant cavity and the detection component, and is used to split the light beam transmitted through the optical resonant cavity to obtain a first light signal and a second light signal.

6. The optical lock cavity system according to claim 5, characterized in that: The detection component includes: a photodetector, a mixer, a radio frequency signal generator, a bandpass filter, and a low noise amplifier; The photodetector is arranged in the same optical path as the third beam splitter, and is used to convert the first optical signal into an intensity signal; The mixer is communicatively connected with the photoelectric detector, and is used for performing difference frequency operation on the intensity signal and the microwave signal from the radio frequency signal generator to generate a difference frequency signal and output the difference frequency signal; The radio frequency signal generator is in communication connection with the mode control component and the mixer, and is used to transmit a microwave signal of a set frequency to the mode control component and the mixer; The bandpass filter is communicatively connected to the mixer and is used for filtering the difference frequency signal; The low noise amplifier is communicatively connected to the band pass filter and is used to amplify the difference frequency signal to obtain an error signal.

7. The optical lock cavity system according to claim 1, characterized in that: The second optical signal can be applied after being emitted through the optical resonant cavity group; the applications include: laser radar, gas detection, and optical atomic clock.

8. An optical cavity lock method, applied to an optical cavity lock system as claimed in any one of claims 1 to 7, characterized in that: include: The laser component and the mode control component are adjusted so that the cavity power of the first laser is less than the cavity power of the second laser, and the combined beam is transmitted through the optical resonant cavity component to generate a second light signal and a transmission peak signal, and then the transmission peak signal is converted into an intensity signal by a photodetector, and the frequency of the microwave signal is set according to the frequency of the intensity signal, and a difference frequency operation is performed on the intensity signal and the microwave signal by a mixer to obtain a difference frequency signal; The difference frequency signal is filtered by a bandpass filter and then input into a low noise amplifier for frequency drift conversion to obtain an error signal; Based on the error signal, a feedback signal is generated by a servo controller and transmitted to a feedback actuator of the laser assembly, so that the deviation value between the frequency of the incident laser generated by the laser assembly and the cavity resonance frequency is within a set range.

9. An optical cavity locking method according to claim 8, characterized in that: The step of adjusting the laser component and the mode control component so that the cavity power of the first laser is less than the cavity power of the second laser, and combining the beams to generate the second light signal and the transmission peak signal through the optical resonant cavity component includes: Adjusting the incident laser power generated by the laser assembly and the mode controller in the mode control assembly until the incident power of the first laser is less than the incident power of the second laser; The high-power component in the mode control component is adjusted so that the first laser generates a transmission peak signal in the resonant cavity component, and the second laser undergoes a nonlinear process in the resonant cavity component to obtain a second optical signal; the second optical signal can be applied, and the applications include: laser radar, gas detection, and optical atomic clock.

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