Laser stabilizing device and laser

Abstract

The invention provides a laser stabilizing device and a laser. The laser stabilizing device comprises an actuator, a frequency controller, a power controller and a driving modulator. The actuator comprises a laser modulation module which is used for adjusting the first laser according to the control signal and outputting the second laser. The frequency controller comprises a frequency error generation module which is used for comparing the frequency of the second laser with the reference frequency and generating a frequency error adjusting signal. The power controller comprises a power error generation module which is used for comparing the power of the second laser with the reference power and generating a power error adjusting signal. The driving modulator comprises a frequency control module and a power control module. The frequency control module is used for generating a radio frequency signal and adjusting the frequency of the radio frequency signal according to a frequency error adjusting signal. The power control module is used for receiving the radio frequency signal output by the frequency control module and adjusting the amplitude of the radio frequency signal according to the power error adjusting signal. And the radio frequency signal is used as a control signal input into the laser modulation module.

Description

Technical Field

[0001] This application relates to the field of laser modulation technology, and in particular to a laser stabilization device and a laser. Background Technology

[0002] Narrow-linewidth lasers are laser sources with extremely narrow output spectral linewidths and long coherence lengths, ranging from megahertz to hertz or even narrower. Compared to other light sources, narrow-linewidth lasers offer high frequency controllability, facilitating high-precision frequency locking and coherent detection. Therefore, they hold significant application potential in fields such as high-resolution spectroscopy, atomic clocks and optical frequency combs, quantum information and cold atom experiments, and precision displacement measurement.

[0003] Existing laser stabilization devices are unable to effectively suppress both frequency noise and intensity noise of the laser simultaneously, and therefore cannot meet the comprehensive performance requirements of laser stabilization devices in different application scenarios. Summary of the Invention

[0004] This application provides a laser stabilization device and a laser.

[0005] A first aspect of this application provides a laser stabilization device, including an actuator, a frequency controller, a power controller, and a drive modulator; The actuator is used to receive a first laser beam; the actuator includes a laser modulation module, which is used to adjust the frequency and power of the first laser beam according to a control signal and output a second laser beam. The frequency controller includes a frequency error generation module, which is used to receive the second laser and compare the frequency of the second laser with a reference frequency to generate a frequency error adjustment signal. The power controller includes a power error generation module, which receives the second laser and compares the power of the second laser with a reference power to generate a power error adjustment signal. The driving modulator includes a frequency control module and a power control module. The frequency control module generates a radio frequency (RF) signal and adjusts the frequency of the RF signal according to the frequency error adjustment signal. The power control module receives the RF signal output by the frequency control module and adjusts the amplitude of the RF signal according to the power error adjustment signal. The RF signal output by the power control module serves as a control signal input to the laser modulation module.

[0006] In some embodiments, the laser modulation module includes a beam reducer, a first aperture, an acousto-optic modulator, a second aperture, a lens, and a plane mirror arranged sequentially along the optical path of the first laser. The acousto-optic modulator is used to adjust the frequency and power of the first laser according to the control signal; The plane mirror is disposed on the focal plane of the lens. After the first laser is reflected by the plane mirror, it passes through the lens, the second aperture, the acousto-optic modulator, the first aperture, and the beam reducer in sequence before being output.

[0007] In some embodiments, the actuator further includes a polarization module and an optical path reversing module; the polarization module is used to receive the first laser and convert the first laser into linearly polarized light with a preset polarization direction; The optical path reversing module is used to deflect the optical path direction of the first laser output through the laser modulation module, and then transmit the first laser with the deflected optical path direction as the second laser to the frequency controller and the power controller.

[0008] In some embodiments, the polarization module includes a Glan prism and a half-wave plate arranged sequentially along the optical path of the first laser. The optical path reversing module is located between the polarization module and the laser modulation module, and includes a first polarization beam splitter and a quarter-wave plate arranged sequentially along the optical path direction of the first laser.

[0009] In some embodiments, the frequency error generation module includes a signal generation unit, a photoelectric modulation unit, a laser frequency stabilization unit, a first photoelectric detection unit, and a mixing unit.

[0010] The signal generation unit is used to generate a frequency modulation signal; the photoelectric modulation unit is used to perform sideband modulation on the second laser according to the frequency modulation signal to generate and output a third laser; the laser frequency stabilization unit is used to perform resonance locking processing on the third laser and reflect and output a fourth laser; the first photoelectric detection unit is used to acquire an interference signal according to the fourth laser; the mixing unit is used to perform frequency modulation processing on the frequency modulation signal and the interference signal to generate a frequency error signal.

[0011] In some embodiments, the frequency error generation module further includes a filtering unit; the filtering unit is used to filter the frequency error signal generated by the mixing unit.

[0012] In some embodiments, the frequency controller further includes a first beam splitting module and a servo control module; The first beam splitting module is used to collect a portion of the second laser and transmit the second laser to the frequency error generation module; the servo control module is used to process the frequency error signal and generate the frequency error adjustment signal.

[0013] In some embodiments, the power error generation module includes a second photoelectric detection unit and a servo control unit. The second photoelectric detection unit is used to detect the second laser and generate a power error signal, and the servo control unit is used to process the power error signal and generate the power error adjustment signal.

[0014] In some embodiments, the power controller further includes a second beam splitting module; the second beam splitting module is used to collect a portion of the second laser and transmit the second laser to the power error generation module.

[0015] A second aspect of this application provides a laser, the laser including a laser emitter and the aforementioned laser stabilization device, the laser emitter being used to emit a first laser, and the laser stabilization device receiving the first laser emitted by the laser emitter and adjusting the frequency and power of the first laser.

[0016] The laser stabilization device provided in this application embodiment receives the second laser output from the actuator via a frequency controller and a power controller. The controller can detect the frequency and power of the second laser, respectively, to obtain frequency error adjustment signals and power error adjustment signals. A drive modulator generates corresponding control signals based on these signals, driving the power control module to adjust the laser's frequency and power. This forms a closed-loop control, ensuring that the second laser's frequency and power match the reference frequency and power, thereby guaranteeing the stability of the second laser's frequency and power. Furthermore, the laser stabilization device can adjust the laser's frequency and power without relying on the laser's own structure, thus adapting to different types of lasers and improving the device's versatility.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this specification and, together with the description, serve to explain the principles of this specification.

[0019] Figure 1 A structural block diagram of a laser stabilization device provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a laser provided in one embodiment of this application; Figure 3 This is a schematic diagram of the structure of a laser provided in another embodiment of this application. Detailed Implementation

[0020] The technical solutions in the embodiments (or "implementations") of this application will be clearly and completely described herein with reference to the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0021] If the embodiments of this application contain terms relating to directional indications or positional relationships (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationships and movement of the components in a specific posture (as shown in the attached figures); if the specific posture changes, the directional indications or positional relationships will also change accordingly. Furthermore, the terms "first" and "second" used in the embodiments of this application are only for descriptive convenience and should not be construed as indicating or implying relative importance.

[0022] The laser stabilization device and laser according to embodiments of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can complement or combine with each other.

[0023] This application provides a laser stabilization device, such as... Figure 1 and Figure 2 As shown, the laser stabilization device 100 includes an actuator 10, a frequency controller 20, a power controller 30, and a drive modulator 40.

[0024] The actuator 10 is used to receive the first laser L1. The actuator 10 includes a laser modulation module 11, which is used to adjust the frequency and power of the first laser L1 according to the control signal and output the second laser L2.

[0025] The frequency controller 20 includes a frequency error generation module 21, which receives the second laser L2 and compares the frequency of the second laser L2 with the reference frequency to generate a frequency error adjustment signal.

[0026] The power controller 30 includes a power error generation module 31, which receives the second laser L2 and compares the power of the second laser L2 with the reference power to generate a power error adjustment signal.

[0027] The driver modulator 40 includes a frequency control module 41 and a power control module 42. The frequency control module 41 generates a radio frequency (RF) signal and adjusts the frequency of the RF signal according to a frequency error adjustment signal. The power control module 42 receives the RF signal output by the frequency control module 41 and adjusts the amplitude of the RF signal according to the power error adjustment signal. The RF signal output by the power control module 42 serves as the control signal for the input laser modulation module 11.

[0028] The laser stabilization device provided in this application embodiment receives the second laser L2 output by the actuator 10 from the frequency controller 20 and the power controller 30, respectively, and can detect the frequency and power of the second laser L2 to obtain frequency error adjustment signals and power error adjustment signals. The drive modulator 40 generates corresponding control signals based on the frequency error adjustment signals and power error adjustment signals, driving the power control module to adjust the frequency and power of the laser. This forms a closed-loop control, ensuring that the frequency and power of the second laser are consistent with the reference frequency and reference power, thereby guaranteeing the stability of the second laser's frequency and power. Furthermore, the laser stabilization device can adjust the frequency and power of the laser without relying on the laser's own structure, thus adapting to different types of lasers and improving the versatility of the laser stabilization device.

[0029] In one embodiment, such as Figure 2 As shown, the laser modulation module 11 includes a beam reducer 111, a first aperture 112, an acousto-optic modulator 113, a second aperture 114, a lens 115, and a plane mirror 116 arranged sequentially along the optical path of the first laser L1. The acousto-optic modulator 113 is used to adjust the frequency and power of the first laser L1 according to a control signal. The plane mirror 116 is disposed on the focal plane of the lens 115. After being reflected by the plane mirror 116, the first laser L1 passes through the lens 115, the second aperture 114, the acousto-optic modulator 113, the first aperture 112, and the beam reducer 111 before being output.

[0030] After the first laser L1 reaches the laser modulation module 11, the beam reducer 111 reduces the diameter of the first laser L1, allowing the first laser L1 to pass smoothly through subsequent optical components.

[0031] The control signal received by the acousto-optic modulator 113 generates ultrasonic waves within the modulator, forming a periodic refractive index grating. When the first laser enters the acousto-optic modulator, diffraction occurs, resulting in +1st or -1st order diffracted light. The +1st or -1st order diffracted light exhibits a frequency shift relative to the incident light; this shift is the frequency of the control signal. By adjusting the frequency of the control signal, the frequency of the first laser can be controlled. The power of the +1st or -1st order diffracted light is related to the power of the control signal; by adjusting the power of the control signal, the power of the laser can be controlled.

[0032] The laser after being modulated by the acousto-optic modulator 113 contains +1st or -1st order diffraction light as well as other light rays. The second aperture 114 can filter out other light rays (such as 0th order light) besides +1st or -1st order diffraction light.

[0033] Lens 115 and plane mirror 116 constitute a cat's eye reflector. After the first laser L1 is reflected by plane mirror 116, it will return precisely along its incident path. Even if the laser frequency changes, the direction of the reflected laser remains almost unchanged, which helps to improve the spatial stability of the laser. The first aperture 112 and the second aperture 114 have the same function. When the laser passes through the acousto-optic modulator 133 again, diffraction will still occur. The first aperture 112 can be used to filter out light rays other than the +1st or -1st order diffracted light in the laser.

[0034] In one embodiment, such as Figure 2 As shown, the actuator 10 also includes a polarization module 12 and an optical path reversing module 13. The polarization module 12 is used to receive the first laser L1 and convert the first laser L1 into linearly polarized light with a preset polarization direction. The optical path reversing module 13 is used to deflect the optical path direction of the first laser L1 output through the laser modulation module 11, and send the first laser L1 with the deflected optical path direction as the second laser L2 to the frequency controller 20 and the power controller 30.

[0035] The polarization module 12 ensures that the laser entering the subsequent optical elements is a single, linearly polarized light with a known direction, and the optical path reversal module 13 ensures that the second laser L2 is input to the frequency controller 20 and the power controller 30 in the correct direction.

[0036] Specifically, the polarization module 12 includes a Glan prism 121 and a half-wave plate 122 arranged sequentially along the optical path direction of the first laser L1. The optical path reversing module 13 is located between the polarization module 12 and the laser modulation module 11, and includes a first polarizing beam splitter 131 and a quarter-wave plate 132 arranged sequentially along the optical path direction of the first laser L1.

[0037] After the first laser L1 is emitted from the laser, it is usually an unpolarized or randomly polarized beam. After passing through the Glan prism 121, the first laser L1 becomes horizontally linearly polarized light. After passing through the half-wave plate 122, its polarization direction is parallel to the transmission axis of the first polarization beam splitter 131, allowing the laser to pass through the first polarization beam splitter 131 and enter subsequent optical elements.

[0038] The first laser L1 is converted from horizontally linearly polarized light to circularly polarized light after passing through the quarter-wave plate 132. After being modulated by the laser modulation module 11, the first laser L1 returns along the original optical path and passes through the quarter-wave plate 132 again. The first laser L1 is converted from circularly polarized light to vertically linearly polarized light. At this time, the first laser L1 cannot pass through the first polarization beam splitter 131. Instead, it is completely reflected by the first polarization beam splitter 131 and output from the actuator 10, becoming the second laser L2.

[0039] In one embodiment, such as Figure 2 As shown, the frequency error generation module 21 includes a signal generation unit 211, a photoelectric modulation unit 212, a laser frequency stabilization unit 213, a first photoelectric detection unit 214, and a mixing unit 215.

[0040] Signal generation unit 211 generates a frequency modulation signal. Photoelectric modulation unit 212 modulates the second laser L2 using the frequency modulation signal to generate and output a third laser L3. Laser frequency stabilization unit 213 resonates and locks the third laser L3, reflecting and outputting a fourth laser L4. First photoelectric detection unit 214 acquires an interference signal based on the fourth laser L4. Mixing unit 215 mixes the frequency modulation signal and the interference signal to generate a frequency error signal.

[0041] Specifically, the signal generation unit 211 is a signal generator; the photoelectric modulation unit 212 is a photoelectric modulator, fiber phase modulator, or acousto-optic modulator; the laser frequency stabilization unit 213 is an FP cavity (Fabry-Pérot cavity) or an ultra-stable cavity; the first photoelectric detection unit 214 is a photodetector, and a lens can be placed in front of the photodetector to focus the laser onto the surface of the photodetector; the mixing unit 215 is a mixer. The frequency error generation module 21 also includes a phase shifter 216 connected between the signal generator and the mixer.

[0042] Signal generation unit 211 generates a frequency modulation signal (e.g., a 20 MHz radio frequency signal) to drive electro-optic modulation unit 212 to modulate the second laser L2, generating a third laser L3 carrying a carrier wave (ν) and a pair of sidebands (ν ± 20 MHz). In the reflected fourth laser L4, the amplitude and phase of the carrier wave and sidebands change with the deviation of the laser frequency ν from the resonant frequency (i.e., the reference frequency). After receiving the fourth laser L4, the first photoelectric detection unit 214 converts the amplitude and phase information it carries into an interference signal containing the frequency modulation signal (20 MHz). The mixing unit 215 multiplies the interference signal with the frequency modulation signal after phase adjustment by a phase shifter to obtain a frequency error signal.

[0043] In one embodiment, such as Figure 2 As shown, the frequency error generation module 21 also includes a filtering unit 217, which is used to filter the frequency error signal generated by the mixing unit 215. The frequency error signal of the filtering unit 217 is filtered out to remove high-frequency noise after passing through a low-pass filter.

[0044] In one embodiment, such as Figure 2 As shown, the frequency error generation module 21 also includes an optical path reversing unit 218, which includes a half-wave plate 2181, a polarization beam splitter 2182, and a quarter-wave plate 2183. The laser light passes sequentially through the half-wave plate 2181, the polarization beam splitter 2182, and the quarter-wave plate 2183 before being reflected from the laser frequency stabilization unit 213. It then passes through the quarter-wave plate 2183 again to reach the polarization beam splitter 2182, which reflects the laser light to the first photoelectric detection unit 214.

[0045] In one embodiment, such as Figure 2 As shown, the frequency controller also includes a first beam splitting module 22 and a servo control module 23. The first beam splitting module 22 is used to acquire a portion of the second laser L2 and transmit the second laser L2 to the frequency error generation module 21. The servo control module 23 is used to process the frequency error signal and generate a frequency error adjustment signal.

[0046] The first beam splitting module 22 includes a beam splitter with a fixed splitting ratio. The beam splitter can split a portion of the beam from the main optical path of the second laser L2 and guide it to the frequency error generation module 21. The servo control module 23 includes a servo controller. The servo controller performs PID calculations on the frequency error signal to obtain a frequency error adjustment signal.

[0047] In one embodiment, such as Figure 2 As shown, the frequency control module 41 includes a voltage-controlled oscillator, which adjusts the frequency of the radio frequency signal according to the frequency error adjustment signal.

[0048] In one embodiment, such as Figure 2 As shown, the power error generation module 31 includes a second photoelectric detection unit 311, which is used to detect the second laser L2 and generate a power error signal. It should be noted that the power error signal here actually reflects the power of the second laser L2.

[0049] The power error generation module 31 also includes a servo control unit 312. The servo control unit 312 is used to compare the power error signal with the reference power and generate a power error adjustment signal.

[0050] The servo control unit 312 receives the power error signal, compares it with the internally set target voltage, generates a power error adjustment signal, and controls the power control module 42 according to the power error adjustment signal to change the amplitude of the radio frequency signal.

[0051] Specifically, the power control module 42 includes a voltage-controlled attenuator, which adjusts the amplitude of the radio frequency signal according to the frequency error adjustment signal. The servo control unit 312 includes a servo controller, which performs PID calculations on the power error signal to obtain the frequency power error adjustment signal.

[0052] In one embodiment, such as Figure 2 As shown, the power controller 30 also includes a second beam splitting module 32, which is used to collect a portion of the second laser beam and transmit the second laser beam to the power error generation module. The second beam splitting module 32 includes a beam splitter with a fixed splitting ratio, which can split a portion of the beam from the main optical path of the second laser L2 and guide it to the power error generation module 31.

[0053] In one embodiment, such as Figure 2 As shown, the drive modulator 40 also includes a power amplification module 43, which amplifies the control signal output by the power control module 42 and sends the amplified control signal to the laser modulation module 11.

[0054] In one embodiment, such as Figure 3 As shown, the laser stabilization device also includes a polarization-maintaining single-mode fiber coupler 50 connected between the first beam-splitting module 22 and the second beam-splitting module 32. The polarization-maintaining single-mode fiber coupler 50 includes a first optical coupling head 51, a polarization-maintaining single-mode fiber 52, and a second optical coupling head 53 arranged sequentially. The first optical coupling head 51 is connected to the first beam-splitting module 22, and the second optical coupling head 53 is connected to the second beam-splitting module 32. The polarization-maintaining single-mode fiber coupler 50 can improve the spatial stability of the second laser L2 propagation.

[0055] This application also provides a laser, such as... Figure 2 As shown, the laser includes a laser emitter 200 and the aforementioned laser stabilization device 100. The laser emitter 200 emits a first laser L1, and the laser stabilization device 100 receives the first laser L1 emitted by the laser emitter 200 and adjusts the frequency and power of the first laser L1.

[0056] In one embodiment, the frequency controller 20 may output a feedback voltage to the laser emitter 200 to prevent the first laser L1 emitted by the laser emitter 200 from drifting over a wide range.

[0057] It should be noted that the technical solutions or features described in the above embodiments can be combined or supplemented with each other without conflict. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the accompanying drawings; all modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A laser stabilization device, characterized in that, Includes actuators, frequency controllers, power controllers, and drive modulators; The actuator is used to receive a first laser beam; the actuator includes a laser modulation module, which is used to adjust the frequency and power of the first laser beam according to a control signal and output a second laser beam. The frequency controller includes a frequency error generation module, which is used to receive the second laser and compare the frequency of the second laser with a reference frequency to generate a frequency error adjustment signal. The power controller includes a power error generation module, which receives the second laser and compares the power of the second laser with a reference power to generate a power error adjustment signal. The driving modulator includes a frequency control module and a power control module. The frequency control module generates a radio frequency (RF) signal and adjusts the frequency of the RF signal according to the frequency error adjustment signal. The power control module receives the RF signal output by the frequency control module and adjusts the amplitude of the RF signal according to the power error adjustment signal. The RF signal output by the power control module serves as a control signal input to the laser modulation module.

2. The laser stabilization device according to claim 1, characterized in that, The laser modulation module includes a beam reducer, a first aperture, an acousto-optic modulator, a second aperture, a lens, and a plane mirror arranged sequentially along the optical path of the first laser. The acousto-optic modulator is used to adjust the frequency and power of the first laser according to the control signal; The plane mirror is disposed on the focal plane of the lens. After the first laser is reflected by the plane mirror, it passes through the lens, the second aperture, the acousto-optic modulator, the first aperture, and the beam reducer in sequence before being output.

3. The laser stabilization device according to claim 2, characterized in that, The actuator further includes a polarization module and an optical path reversing module; the polarization module is used to receive the first laser and convert the first laser into linearly polarized light with a preset polarization direction; The optical path reversing module is used to deflect the optical path direction of the first laser output through the laser modulation module, and then transmit the first laser with the deflected optical path direction as the second laser to the frequency controller and the power controller.

4. The laser stabilization device according to claim 3, characterized in that, The polarization module includes a Glan prism and a half-wave plate arranged sequentially along the optical path of the first laser. The optical path reversing module is located between the polarization module and the laser modulation module, and includes a first polarization beam splitter and a quarter-wave plate arranged sequentially along the optical path direction of the first laser.

5. The laser stabilization device according to claim 1, characterized in that, The frequency error generation module includes a signal generation unit, a photoelectric modulation unit, a laser frequency stabilization unit, a first photoelectric detection unit, and a mixing unit; The signal generation unit is used to generate a frequency modulation signal; the photoelectric modulation unit is used to perform sideband modulation on the second laser according to the frequency modulation signal to generate and output a third laser; the laser frequency stabilization unit is used to perform resonance locking processing on the third laser and reflect and output a fourth laser; the first photoelectric detection unit is used to acquire an interference signal according to the fourth laser; the mixing unit is used to perform frequency modulation processing on the frequency modulation signal and the interference signal to generate a frequency error signal.

6. The laser stabilization device according to claim 5, characterized in that, The frequency error generation module further includes a filtering unit; the filtering unit is used to filter the frequency error signal generated by the mixing unit.

7. The laser stabilization device according to claim 5, characterized in that, The frequency controller also includes a first beam splitting module and a servo control module; The first beam splitting module is used to collect a portion of the second laser and transmit the second laser to the frequency error generation module; the servo control module is used to process the frequency error signal and generate the frequency error adjustment signal.

8. The laser stabilization device according to claim 1, characterized in that, The power error generation module includes a second photoelectric detection unit and a servo control unit. The second photoelectric detection unit is used to detect the second laser and generate a power error signal. The servo control unit is used to process the power error signal and generate the power error adjustment signal.

9. The laser stabilization device according to claim 8, characterized in that, The power controller further includes a second beam splitting module; the second beam splitting module is used to collect a portion of the second laser and transmit the second laser to the power error generation module.

10. A laser, characterized in that, The laser includes a laser emitter and a laser stabilization device as described in any one of claims 1 to 9, wherein the laser emitter is used to emit a first laser, and the laser stabilization device receives the first laser emitted by the laser emitter and adjusts the frequency and power of the first laser.

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