CN117394136B - Laser frequency locking device and method - Google Patents
Laser frequency locking device and method Download PDFInfo
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- CN117394136B CN117394136B CN202311499468.5A CN202311499468A CN117394136B CN 117394136 B CN117394136 B CN 117394136B CN 202311499468 A CN202311499468 A CN 202311499468A CN 117394136 B CN117394136 B CN 117394136B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/068—Stabilisation of laser output parameters
- H01S5/0683—Stabilisation of laser output parameters by monitoring the optical output parameters
- H01S5/0687—Stabilising the frequency of the laser
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/13—Stabilisation of laser output parameters, e.g. frequency or amplitude
- H01S3/1305—Feedback control systems
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/13—Stabilisation of laser output parameters, e.g. frequency or amplitude
- H01S3/136—Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling devices placed within the cavity
- H01S3/137—Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling devices placed within the cavity for stabilising of frequency
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/068—Stabilisation of laser output parameters
- H01S5/06817—Noise reduction
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Abstract
本发明公开了一种激光器频率锁定装置和方法，通过将激光器中发出的激光入射到光反馈组件后产生反射光，该反射光中的一部分入射到PI D反馈调节组件，经过PI D反馈调节组件接收该部分反射光，对该部分反射光对应的电信号解调后得到误差信号，激光器的控制端根据误差信号控制激光频率锁定在预设频率宽度上。本实施例公开的装置和方法，将光学反馈和电子PI D反馈调节的技术相结合，利用电子PI D反馈调节的方法对光学反馈锁定后的激光频率锁定在预设频率上，以实现对激光器频率的长期锁定，本实施例公开的装置和方法，实施方便，可以应用于不同波段和不同类型的激光器，具有广泛的适用性。
The present invention discloses a laser frequency locking device and method, wherein the laser emitted from the laser is incident on an optical feedback component to generate reflected light, a part of the reflected light is incident on a PID feedback adjustment component, the PID feedback adjustment component receives the part of the reflected light, and an error signal is obtained after demodulating the electrical signal corresponding to the part of the reflected light. The control end of the laser controls the laser frequency to be locked at a preset frequency width according to the error signal. The device and method disclosed in this embodiment combine the technology of optical feedback and electronic PID feedback adjustment, and use the electronic PID feedback adjustment method to lock the laser frequency after optical feedback locking at a preset frequency, so as to achieve long-term locking of the laser frequency. The device and method disclosed in this embodiment are easy to implement, can be applied to lasers of different bands and different types, and have wide applicability.
Description
Technical Field
The invention relates to the technical field of laser control, in particular to a device and a method for locking the frequency of a laser.
Background
The single frequency characteristics of lasers are one of the important parameters of interest in applications in the optoelectronic industry and related fields. However, the free-running laser is inevitably affected by external environmental temperature, vibration and electromagnetism, so that the linewidth of the free-running laser is wide and the center frequency of the free-running laser shifts, and therefore, in the fields of precision machining, precision measurement and the like, the frequency of the free-running laser is usually required to be locked to obtain the linewidth of the laser as narrow as possible.
Integrated semiconductor lasers, which typically have an operating linewidth on the order of MHz, limit further applications due to the effects of spontaneous radiation. The optical feedback technology is an effective method for suppressing the frequency noise of the semiconductor laser, but when the frequency noise is limited in a small range, the line width can be kept narrow all the time, so that the pure optical feedback method is difficult to apply to the application requiring long-term locking.
Accordingly, the prior art is still further improved.
Disclosure of Invention
The invention aims to provide a device and a method for locking the frequency of a laser, which overcome the defect that the laser frequency cannot be locked in a smaller range for a long time by simply relying on an optical feedback technology in the prior art.
The technical scheme adopted for solving the technical problems is as follows:
In a first aspect, the present embodiment discloses a laser frequency locking device, including: the device comprises a laser, an optical feedback assembly and a PID feedback adjustment assembly;
The laser is used for emitting laser;
the optical feedback component is arranged on the optical path of the laser and is used for receiving the laser emitted by the laser and generating reflected light;
The PID feedback adjusting component is used for receiving part of reflected light in the reflected light generated by the optical feedback component, demodulating an electric signal corresponding to the part of reflected light to obtain an error signal, and transmitting the error signal to a control end of the laser, so that the control end of the laser controls the laser to be locked on a preset frequency width according to the error signal.
Optionally, the PID feedback adjustment assembly includes: the device comprises a first photoelectric detector, a phase detection device and a first PID locking device;
the first photoelectric detector is used for detecting the optical signal of the received partial reflected light and converting the optical signal of the partial reflected light into a first electric signal;
The phase detection device is used for demodulating to obtain the first electric signal, obtaining an error signal and transmitting the error signal to the first PID locking device;
The first PID locking device is used for transmitting the received error signal to the control end of the laser.
Optionally, the PID feedback adjustment assembly further comprises: a radio frequency generating and amplifying device; the radio frequency generation and amplification device is arranged between the laser and the phase detection device and is used for generating a sinusoidal radio frequency signal and amplifying the sinusoidal radio frequency signal, and transmitting the sinusoidal radio frequency signal to the phase detection device so that the phase detection device can demodulate a first electric signal by utilizing the sinusoidal radio frequency signal to obtain the error signal.
Optionally, the optical feedback assembly includes: the optical resonant cavity, the second photoelectric detector and the second PID locking device;
the optical resonant cavity is used for receiving laser emitted by the laser, respectively generating reflected light and transmitted light, and forming optical feedback in the cavity by utilizing an optical feedback cavity ring-down technology;
the second photodetector is configured to receive the transmitted light transmitted by the optical resonant cavity, convert the transmitted light into a second electrical signal, and transmit the second electrical signal to the second PID locking device;
The second PID locking device is used for receiving the second electric signal and outputting feedback voltage generated according to the second electric signal to the laser.
Optionally, an optical feedback assembly is further disposed between the laser: a feedback adjustment element;
The feedback regulating element comprises a polaroid, an attenuation sheet, an optical isolator and a wave plate;
the laser emitted by the laser sequentially passes through the polaroid, the attenuation sheet, the optical isolator and the wave plate and then enters the optical feedback assembly.
Optionally, the optical feedback assembly further comprises a reflective mirror plate and a lens matching element;
The reflecting mirror plate and the lens matching element are arranged between the light splitting element and the optical resonant cavity and are used for adjusting the phase of reflected light emitted by the optical resonant cavity and improving the power of the reflected light emitted by the optical feedback component.
Optionally, the optical feedback component is further connected with a lock-in amplifier; the phase-locked amplifier is arranged between the second PID locking device and the second photoelectric detector;
the phase-locked amplifier is used for receiving the second electric signal converted by the second photoelectric detector and modulating and demodulating the second electric signal.
In a second aspect, the present embodiment further discloses a method for locking a frequency of a laser, where the method includes:
the method comprises the steps that a laser beam emitted by a laser is incident to an optical feedback assembly, and the optical feedback assembly emits reflected light after receiving the laser beam;
the PID feedback adjusting component receives part of reflected light in the reflected light emitted by the optical feedback component, demodulates an electric signal corresponding to the part of reflected light to obtain an error signal, and transmits the error signal to a control end of the laser, so that the control end of the laser controls the laser frequency to be locked on a preset frequency width according to the error signal.
Optionally, the PID feedback adjustment assembly includes: the device comprises a first photoelectric detector, a phase detection device and a first PID locking device;
The step of receiving the partial reflected light sent by the optical feedback component by the PID feedback adjusting component, demodulating an electric signal corresponding to the partial reflected light to obtain an error signal, and transmitting the error signal to a control end of a laser comprises the following steps:
detecting the received partial reflected light by using a first photoelectric detector, and converting an optical signal of the partial reflected light into a first electric signal;
demodulating the first electric signal by using a phase detection device to obtain an error signal, and transmitting the error signal to the first PID locking device;
And transmitting the received error signal to a control end of the laser by using the first PID locking device.
Optionally, the optical feedback assembly includes: an optical resonant cavity; the preset frequency width is one longitudinal mode of the optical resonant cavity.
The beneficial effects are that:
The embodiment discloses a laser frequency locking device and a method, wherein the locking device comprises: the device comprises a laser to be frequency locked, a light splitting element, an optical feedback assembly and a PID feedback adjusting assembly. After laser emitted in the laser device is incident to the optical feedback assembly, the optical feedback assembly generates reflected light, a part of the reflected light is incident to the PID feedback adjustment assembly, the PID feedback adjustment assembly receives the part of reflected light, demodulates an electric signal corresponding to the part of reflected light to obtain an error signal, and transmits the error signal to a control end of the laser device, so that the control end of the laser device controls the laser frequency to be locked on a preset frequency width according to the error signal. The device and the method disclosed by the embodiment combine the technology of optical feedback and electronic PID feedback regulation, lock the laser frequency after optical feedback locking on the preset frequency by utilizing the method of electronic PID feedback regulation so as to realize long-term locking of the laser frequency, are convenient to implement, can be applied to lasers with different wave bands and different types, and have wide applicability.
Drawings
FIG. 1 is a schematic diagram of a frequency locking device of a laser according to an embodiment of the present invention;
FIG. 2 is a flowchart showing steps of a method for locking laser frequency according to an embodiment of the present invention;
FIG. 3 is a graph showing noise contrast for three different locking techniques in accordance with an embodiment of the present invention.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
The laser emitted by the laser has the advantages of single frequency, collimation and high brightness, and is widely applied in the fields of scientific research and industrial application. However, the free-running laser is affected by external environmental temperature, vibration or electromagnetic, and the linewidth of the emitted laser is relatively wide, usually at hundred khz, and the center frequency of the laser has long-term drift, so in the field based on precision machining or precision measurement, the frequency linewidth of the laser needs to be narrowed to obtain narrow linewidth laser with stable frequency.
The linewidth of the external cavity feedback laser in the prior art meets the requirement of the precision machining or precision measurement field on the stable frequency of the laser, but the external cavity feedback laser has the following defects: a narrow linewidth laser that is portable, compact, single-mode, tunable, and low in cost is also needed because it is bulky, difficult to carry, expensive, and prone to die-hopping. The advantages of the above parts are met by the present integrated semiconductor lasers, such as distributed feedback lasers, but their operating linewidth is typically at the MHz level due to the effects of spontaneous radiation, limiting further applications.
The optical feedback technology is an effective method for inhibiting the frequency noise of the semiconductor laser, but the line width can be kept narrow all the time only when the feedback intensity is in a small range of about-45 to-39 dB, and the coherent collapse or mode-jump phenomenon can occur when the feedback intensity is slightly stronger or weaker than the intensity. When the laser frequency drifts out of the self-locking range, the optical feedback cannot generate the effect of narrowing the line width, so that the pure optical feedback method is difficult to be used in applications needing long-term locking, such as detection laser, clock laser, molecular optical frequency reference and the like for precise measurement. The electronic feedback can control the drift of the environment, but is limited by bandwidth, so that the electronic feedback method is difficult to control the laser with high noise, and therefore, no laser in the prior art can simultaneously meet the requirements of narrow linewidth and long-term locking.
In order to solve the problems in the laser, the embodiment discloses a device and a method for locking the frequency of the laser, which combine an optical feedback technology and an electronic feedback technology to realize continuous narrowing of the frequency of the laser and stable frequency so as to meet the application of the laser in the fields of precise control, industry or national defense and the like.
The apparatus and method disclosed in this embodiment are further described below with reference to the accompanying drawings.
Referring to fig. 1, this embodiment discloses a laser frequency locking device, as shown in fig. 1, including: a laser 100, an optical feedback assembly 300, and a PID feedback adjustment assembly 200.
The laser 100 is configured to emit laser light.
The optical feedback assembly 300 is disposed on the optical path of the laser, and is configured to receive the laser light emitted by the laser and generate reflected light.
The PID feedback adjusting component 200 is configured to receive a portion of the reflected light generated by the optical feedback component, demodulate an electrical signal corresponding to the portion of the reflected light to obtain an error signal, and transmit the error signal to a control end of the laser, so that the control end of the laser controls the laser to be frequency-locked on a preset frequency width according to the error signal.
In one embodiment, the reflected light generated in the optical feedback assembly 300 is split into two beams by a beam splitting element, one beam is incident into the PID feedback adjustment assembly 200, and the other beam is incident into the laser 100 to form optical feedback.
Specifically, as shown in fig. 1, the light splitting element 400 is disposed on the optical path of the reflected light, and the reflected light generated by the optical feedback assembly is split into two parts by the light splitting element.
The PID feedback adjusting component 200 receives part of the reflected light, demodulates an electric signal corresponding to the part of the reflected light to obtain an error signal, and transmits the error signal to a control end of the laser, so that the control end of the laser controls the laser frequency to be locked on a preset frequency width according to the error signal.
The method provided by the embodiment can be applied to lasers with different wave bands and/or different types, for example: the external cavity type semiconductor laser, the optical fiber laser, the solid laser, the distributed feedback type semiconductor laser and the distributed Bragg diffraction laser can achieve good frequency locking effect for different types of lasers.
Referring to fig. 1, laser light emitted from a laser 100 is incident into an optical feedback module 300, and the incident laser light is reflected by a mirror disposed in the optical feedback to obtain reflected light. Since the beam splitter 400 is disposed between the laser 100 and the optical feedback assembly 300, the reflected light is split into two beams of laser light after passing through the beam splitter 400, wherein one part of the reflected light is transmitted to the laser 100 to form optical feedback, the other part of the reflected light is incident into the PID feedback adjustment assembly 200, the PID feedback adjustment assembly 200 converts the received optical signal of the part of the reflected light into a first electrical signal, demodulates the first electrical signal to obtain an error signal, and transmits the error signal to the control end of the laser 100, so that the control end of the laser 100 adjusts the frequency of the laser according to the error signal, and the adjusted frequency of the laser 100 is stabilized on a preset frequency width for a long time.
In one embodiment, the light splitting element may be a light splitting prism or a light splitting sheet, so as to split the reflected light reflected in the optical feedback assembly into two beams.
Specifically, the PID feedback adjusting component converts the received partial reflected light into an electrical signal, demodulates the electrical signal to obtain an error signal, and is used for adjusting and controlling the optical path between the laser output by the laser and the reflected light output by the optical feedback component, and adjusting the feedback phase in real time, so as to realize that the output frequency of the laser is stabilized on a preset frequency width.
Specifically, as shown in connection with fig. 1, the PID feedback adjustment assembly 200 includes: a first photodetector 230, a phase detection device 240 and a first PID locking device 220.
The first photodetector 230 is disposed on the optical path of the partially reflected light, and is configured to detect an optical signal of the partially reflected light, and convert the optical signal of the partially reflected light into an electrical signal.
The phase detecting device 240 is electrically connected to the first photo detector 230, and is configured to demodulate the electrical signal converted by the first photo detector 230, obtain an error signal, and transmit the error signal to the first PID locking device 220.
The first PID locking device 220 is connected to the phase detecting device 240, and is configured to receive an error signal sent by the phase detecting device 240, and transmit the received error signal to a control end of the laser 100.
Specifically, the first PID locking device 220 adjusts the phase and the magnitude of the received error signal, and transmits the error signal with the adjusted phase and magnitude to the control end of the laser 100, so as to ensure that the phase of the unit gain in the error signal received by the control end of the laser 100 does not exceed 180 degrees, thereby ensuring the stability of the error signal.
Specifically, the control end of the laser adjusts the optical path between the laser and the optical resonant cavity according to the received error signal, so as to complete dynamic adjustment of the feedback phase, and the frequency of the laser after dynamic adjustment is locked on a longitudinal mode of the optical resonant cavity.
The PID feedback adjustment assembly 200 further comprises: a radio frequency generating and amplifying device 210; the rf generating and amplifying device 210 is disposed between the laser 100 and the phase detecting device 240.
The rf amplifying device 210 is configured to generate a sinusoidal rf signal and amplify the sinusoidal rf signal.
In one embodiment, the radio frequency generating amplification device 210 includes: a phase shifting element, a precision RF frequency source element and an RF amplifier; the phase shifting element is used for adjusting the relative phase difference between the two signals during phase detection. A precision RF frequency source element for generating a precision sinusoidal RF signal. And the radio frequency amplifier is used for amplifying the sinusoidal radio frequency signal generated by the precise radio frequency source element.
Specifically, the radio frequency amplifying device further transmits the generated sinusoidal radio frequency signal to the phase detecting device, so that the phase detecting device demodulates the first electric signal by using the sinusoidal radio frequency signal to obtain the error signal.
Further, the optical feedback assembly 300 includes: an optical resonant cavity 320, a second photodetector 330, and a second PID locking device 340.
The optical resonator 320 is configured to receive the laser light emitted from the laser 100 and generate reflected light.
In one embodiment, the optical resonant cavity is a Fabry-Perot (Fabry-Perot) optical resonant cavity, and the optical resonant cavity mainly comprises two opposite reflecting mirrors with high reflectivity, wherein the back surfaces of the reflecting mirrors are electroplated with an antireflection film. The material of the cavity uses a material having a lower coefficient of thermal expansion. The reflector and the cavity can be combined in a glue connection or mechanical connection mode to form an optical resonant cavity, and the linewidth of a cavity mode is less than 100kHz.
The second photodetector 330 is connected to the optical resonator, and is configured to receive the transmitted light transmitted by the optical resonator.
Further, between the optical feedback assembly 300 and the laser 100, there are further provided: the adjustment element 500 is fed back.
The feedback adjustment element 500 is configured to receive laser light emitted by the laser, and filter the received laser light and change the polarization state, so as to reduce attenuation of the incident laser light.
In one embodiment, the feedback conditioning element 500 includes a polarizer, an attenuator, an optical isolator, and a wave plate. The laser emitted by the laser sequentially passes through the polaroid, the attenuation sheet, the optical isolator and the wave plate and then enters the optical feedback assembly.
Further, as described in connection with fig. 1, the optical feedback assembly further includes a reflective mirror plate 310 and a lens matching element 360.
The reflecting mirror plate 310 and the lens matching element 360 are disposed between the beam splitting element 400 and the optical resonant cavity 320, and are used for adjusting the phase of the reflected light emitted by the optical resonant cavity 320 and increasing the power of the reflected light emitted by the optical feedback component.
The reflecting mirror 310 is a piezoelectric driven reflecting mirror, and is used for automatically adjusting the reflecting angle according to the received electric signal, so as to adjust the transmission angle and the phase of the reflected light.
The transmission matching element 360, which is formed by a lens group, can transform the laser beam waist to match the mode of the optical field and the mode of the optical resonator, and increase the power of the laser incident on the optical resonator.
Further, referring to fig. 1, the optical feedback assembly 300 is further connected to a lock-in amplifier 350; the lock-in amplifier 350 is disposed between the second PID locking device 340 and the second photo detector 330.
The lock-in amplifier 350 is configured to receive the second electrical signal converted by the second photodetector 330, and modulate and demodulate the second electrical signal.
The second photodetector 330 is used for detecting the transmitted light emitted from the optical resonator 320, converting the transmitted light into an electrical signal, and transmitting the electrical signal to the lock-in amplifier 350. The lock-in amplifier is used for modulating and demodulating the received electric signal.
The second PID locking device 340 is configured to receive the second electrical signal transmitted by the lock-in amplifier 350, and output a feedback voltage generated according to the second electrical signal to the laser, so that the laser adjusts the frequency of the laser according to the feedback voltage.
The method for locking the laser frequency provided by the embodiment utilizes the PID locking device to transmit the feedback part to the control end of the laser, and utilizes the control end of the laser to directly control the laser frequency according to an error signal, so that the method of the embodiment has two layers of locking control, one layer is the first layer of locking control formed by utilizing the optical feedback assembly, and the other layer is the environment anti-interference performance of the laser frequency, which is stronger and provided by the method of the embodiment, on the basis of locking control of the laser frequency by the optical feedback assembly, the two layers of locking control are formed by again locking the laser frequency by utilizing the PID feedback adjusting assembly, and because the optical feedback assembly locks the laser frequency, the effect of narrowing line width cannot be generated by optical feedback after the laser frequency drifts out of a locking range occurs, and the drift generated in the optical feedback assembly is controlled by utilizing the PID feedback adjusting assembly in the embodiment, so that the long-term stable locking of the laser frequency can be realized.
Specifically, in implementation, the device control principle provided in this embodiment includes the following:
First, a laser is selected for frequency locking, which may be a different type and band of lasers, preferably a distributed feedback semiconductor laser may be used.
The laser is controlled to emit laser, and the laser emitted by the laser sequentially passes through the polaroid, the attenuation sheet, the optical isolator and the wave plate in the feedback regulating element, then enters the light splitting element, passes through the light splitting element, enters the lens matching element and the reflecting lens, and then enters the optical resonant cavity.
After being reflected for many times by the reflecting mirrors arranged in the cavities oppositely, part of the laser light entering the optical resonant cavity is reflected out of the cavities and sequentially transmitted to the reflecting mirror plate and the lens matching element, the laser light is divided into two beams after being transmitted to the light splitting element, one beam is transmitted to the laser after passing through the feedback adjusting element, and the other beam is transmitted to the first photoelectric detector.
The first reflected light beam transmitted to the laser forms optical feedback, and after the partial reflected light transmitted to the first photoelectric detector is detected by the first photoelectric detector, the first photoelectric detector converts an optical signal into an electric signal according to the detected light intensity and transmits the electric signal to the phase detection device.
The phase detection device demodulates the received electric signal converted by the first photoelectric detector to obtain an error signal, and transmits the error signal to the first PID locking device, the first PID locking device transmits the error signal to the control end of the laser, and the control end of the laser adjusts the frequency of the laser according to the received error signal, so that the center frequency of the laser to be detected is locked on one longitudinal mode of the optical resonant cavity, and the center frequency of the laser to be locked and the locking of the mode of the optical resonant cavity are obtained.
In addition, the light transmitted from the optical resonant cavity is detected by a second photoelectric detector, the second photoelectric detector converts the detected light signal into an electric signal and transmits the electric signal to the lock-in amplifier so as to realize the adjustment of the phase in the electric signal, and the adjusted electric signal is transmitted to a second PID locking device. The second PID locking device adjusts the received electric signal and transmits the electric signal to the reflecting mirror plate. The reflecting mirror automatically adjusts the dynamic adjustment of the feedback phase according to the received electrical signal.
The method provided by the embodiment combines the optical feedback method and the electronic feedback method to realize the line width narrowing and noise elimination of different types of lasers. The method can realize the long-term stability of the frequency of the laser, narrow linewidth and output stable laser frequency reference.
The embodiment also discloses a method for locking the frequency of the laser on the basis of the device, as shown in fig. 2, comprising the following steps:
step S1, laser beams emitted by a laser are incident to an optical feedback assembly, and the optical feedback assembly emits reflected light after receiving the laser beams.
And S2, the light splitting element divides the reflected light generated by the optical feedback assembly into two parts, wherein one part of the reflected light is incident to the PID feedback adjustment assembly, and the other part of the reflected light is incident to the laser to form optical feedback.
And S3, the PID feedback adjusting component receives the partial reflected light, demodulates an electric signal corresponding to the partial reflected light to obtain an error signal, and transmits the error signal to a control end of the laser, so that the control end of the laser controls the laser frequency to be locked on a preset frequency width according to the error signal.
Further, the PID feedback adjustment assembly comprises: the device comprises a first photoelectric detector, a phase detection device and a first PID locking device;
the PID feedback adjusting component receives the partial reflected light, demodulates an electric signal corresponding to the partial reflected light to obtain an error signal, and transmits the error signal to a control end of the laser, wherein the PID feedback adjusting component comprises the following steps:
detecting an optical signal of the received partial reflected light by using a first photoelectric detector, and converting the optical signal of the partial reflected light into an electrical signal;
demodulating the electric signal by using a phase detection device to obtain an error signal, and transmitting the error signal to the first PID locking device;
And transmitting the received error signal to a control end of the laser by using the first PID locking device.
Further, the optical feedback assembly includes: an optical resonant cavity; the preset frequency width is one longitudinal mode of the optical resonant cavity.
The laser frequency locking device and the method disclosed by the embodiment combine the technology of optical feedback and electronic PID feedback regulation, lock the laser frequency after the optical feedback locking on one longitudinal mode of the optical resonant cavity by utilizing the method of electronic PID feedback regulation, so as to realize long-term narrowing and locking of the laser frequency, thereby meeting the requirements of the fields of precision machining, precision measurement and the like on the laser.
The noise comparison of the three different methods after the closed loop is shown in fig. 3, so that the method provided by the implementation can realize the long-term frequency locking of the laser compared with the other different methods.
Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of the application following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the application pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or N embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
Logic and/or steps represented in the flowcharts or otherwise described herein, e.g., a ordered listing of executable instructions for implementing logical functions, can be embodied in any computer-readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions.
It is to be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the N steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. As with the other embodiments, if implemented in hardware, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.
It will be appreciated that the above embodiments are exemplary and are not to be construed as limiting the application, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the application.
Claims (4)
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| CN113178773B (en) * | 2021-04-16 | 2024-05-24 | 山西大学 | Method for dynamically controlling feedback phase in optical feedback locking cavity technology |
| EP4473627A2 (en) * | 2022-02-04 | 2024-12-11 | Stable Laser Systems, Inc. | Laser frequency stabilization |
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