Laser generation device and method based on frequency self-locking

Abstract

The invention provides a laser generating device and method based on frequency self-locking, and the device comprises a local oscillator laser which is used for generating a laser signal; the oscillation loop is used for generating a first oscillation radio frequency signal based on the laser signal, the oscillation loop comprises a controller, and the frequency of the oscillation radio frequency signal is adjusted by adjusting the state of the controller; and the self-locking module is used for carrying out frequency scanning on the laser, detecting the power and the frequency of the oscillation radio-frequency signal, and locking the frequency of the laser signal by locking the frequency of the first oscillation radio-frequency signal when the frequency of the oscillation radio-frequency signal reaches a preset frequency range.

Description

Technical Field

[0001] The present invention relates to the technical field of laser frequency self-locking, and in particular to a laser generating device and method based on frequency self-locking. Background Art

[0002] Ultra-stable frequency, low-noise, ultra-narrow linewidth lasers have extremely important applications in precision measurement, optical atomic clocks, time-frequency transfer, and low-noise microwave generation. This ultra-stable laser is usually obtained by frequency locking a free-running single-frequency laser. For a free-running laser, the laser output frequency is usually an irregular fluctuation over time due to the influence of various factors such as environmental conditions. To stabilize the laser frequency, frequency locking technology must be used, so frequency locking technology has become an indispensable means in modern precision measurement technology.

[0003] The resonant frequencies of atomic and molecular fine transition spectra, optical interferometers, and ultra-stable optical resonators can all be used as reference frequencies to generate error signals that reflect the instability of the laser frequency, and the signals are fed back to the laser frequency adjustment actuator to lock the frequency of the laser. The laser frequency locking system needs to be re-locked after system relocation, power failure and restart, output frequency adjustment, or abnormal locking state to restore a stable working state. Automatic locking technology is indispensable for the system to quickly achieve a stable working state without human intervention, and is of great significance for the practical application of frequency-stabilized lasers.

[0004] The currently widely used ultra-stable optical reference cavity (Pound-Drever-Hall, PDH) has successfully reduced the frequency instability of single-frequency lasers of different types and wavelengths to less than 10-14@1s, narrowed the line width to the sub-hertz level, and also achieved automatic frequency locking of the laser. However, due to the different locking principles, the existing automatic laser frequency locking scheme is not applicable to all frequency locking schemes, and it is necessary to design and realize automatic frequency locking of the laser according to different locking principles. Summary of the invention

[0005] In view of the above problems, the present invention provides a laser generating device and method based on frequency self-locking.

[0006] An embodiment of the present invention provides a laser generating device based on frequency self-locking, comprising: a local oscillator laser, used to generate a laser signal; an oscillation loop, used to generate a first oscillation radio frequency signal based on the laser signal, the oscillation loop comprising a controller, and the frequency of the oscillation radio frequency signal is adjusted by adjusting the state of the controller; a self-locking module, used to perform frequency scanning on the laser and detect the power and frequency of the oscillation radio frequency signal, and when the frequency of the oscillation radio frequency signal reaches a preset frequency range, the frequency of the laser signal is locked by locking the frequency of the first oscillation radio frequency signal.

[0007] According to an embodiment of the present invention, the self-locking module includes: a microprocessor and a phase-locking unit; the microprocessor includes an input end, a first output end, a second output end, and a third output end; an oscillating radio frequency signal is received through the input end to detect the frequency of the oscillating radio frequency signal, the state of the controller is adjusted by outputting a signal at the first output end to adjust the frequency of the oscillating radio frequency signal, a scanning voltage signal is output through the second output end to scan the frequency of the laser and an adjustment voltage is output to adjust the frequency of the laser signal output by the local oscillator laser, and the third output end communicates with the phase-locking module so that the phase-locking module outputs a locking signal to lock the frequency of the first oscillating radio frequency signal to lock the frequency of the laser signal.

[0008] According to an embodiment of the present invention, the oscillation loop includes: an optical phase modulator, which is used to modulate a microwave signal onto a laser signal to obtain a modulated optical signal; an optical filter, which is used to perform notch filtering on the modulated optical signal to obtain an optical signal after notch filtering; a photodetector, which is used to perform beat frequency on the optical signal after notch filtering to obtain a second oscillation radio frequency signal; an radio frequency amplifier, which is used to amplify the second oscillation radio frequency signal to obtain a first oscillation radio frequency signal; and a power divider, which is used to divide the first oscillation radio frequency signal into two first oscillation radio frequency signals with equal power, one of which is output to the optical phase modulator and the other is input to the microprocessor.

[0009] According to an embodiment of the present invention, the self-locking module performs a frequency scan on the laser and detects the power and frequency of the oscillating radio frequency signal, including: when the power of the first oscillating radio frequency signal reaches a power threshold, recording the amplitude of the scanning voltage signal at this time, and calculating the frequency of the first oscillating radio frequency signal; when the scanning voltage completes a cycle of scanning, obtaining the corresponding relationship between the adjustment voltage of the local oscillator laser and the frequency of the first oscillating radio frequency signal; based on the corresponding relationship between the adjustment voltage and the frequency of the first oscillating radio frequency signal, determining the adjustment voltage corresponding to the optimal first radio frequency oscillation frequency.

[0010] According to an embodiment of the present invention, the self-locking module further comprises:

[0011] The analog-to-digital converter is arranged between the power divider and the microprocessor, and is used for converting the oscillating radio frequency signal into a digital signal and then inputting the digital signal into the microprocessor to detect the frequency of the first oscillating radio frequency signal.

[0012] According to an embodiment of the present invention, the microprocessor is also used to: after the frequency of the laser signal and the first oscillation radio frequency signal are successfully locked, monitor the frequency and power of the oscillation radio frequency signal through the input end; after the oscillation loop is unlocked, lock the frequency of the first oscillation radio frequency signal again to lock the frequency of the laser signal.

[0013] According to an embodiment of the present invention, the phase-locked unit includes a phase-locked loop or a combination of a mixer and a feedback controller.

[0014] According to an embodiment of the present invention, the controller comprises a phase shifter or an adjustable delay line.

[0015] According to an embodiment of the present invention, the device further includes: an optical coupler, which is arranged between the output end of the local oscillator laser and the input end of the optical phase modulator, and is used to output a locked laser signal.

[0016] An embodiment of the present invention also provides a laser generation method based on frequency self-locking, comprising: generating a laser signal through a local oscillator laser; generating a first oscillation radio frequency signal based on the laser signal through an oscillation loop, the oscillation loop includes a controller, and the frequency of the oscillation radio frequency signal is adjusted by adjusting the state of the controller; performing frequency scanning on the laser and detecting the power and frequency of the oscillation radio frequency signal through a self-locking module, and when the frequency of the oscillation radio frequency signal reaches a preset frequency range, locking the frequency of the laser signal by locking the frequency of the first oscillation radio frequency signal; after locking the frequency of the laser signal, outputting the locked laser signal.

[0017] The laser generating device and method based on frequency self-locking provided by the present invention have at least the following technical effects:

[0018] By setting a self-locking module and setting a controller in the oscillation loop, the frequency and power of the oscillating RF signal are detected in real time based on the self-locking module, and the state of the controller is adjusted based on the detection result, thereby adjusting the frequency of the oscillating RF signal of the oscillation loop, thereby achieving the locking of a specific laser signal frequency. By adjusting the controller in the loop, any RF oscillation frequency can be achieved, thereby locking the frequency of the local oscillator laser to any value.

[0019] The operating frequency range of the oscillating radio frequency signal is determined by scanning the frequency of the laser to limit the voltage output range of the phase-locked loop during the phase-locked process, thereby satisfying that the oscillation frequency of the radio frequency oscillation loop is not a continuous value.

[0020] After locking, the frequency and power of the oscillating RF signal are monitored to achieve real-time monitoring of the locking working status, thereby achieving rapid re-locking after loss of lock.

[0021] The laser frequency can be automatically locked by setting the program. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above contents and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0023] Figure 1 A schematic diagram of the structure of a laser generating device based on frequency self-locking according to a first embodiment of the present invention is shown;

[0024] Figure 2 A schematic diagram showing the structure of a self-locking module in a laser generating device based on frequency self-locking according to a second embodiment of the present invention;

[0025] Figure 3 A schematic diagram of the structure of a laser generating device based on frequency self-locking according to a third embodiment of the present invention is shown;

[0026] Figure 4 A schematic diagram of the structure of a laser generating device based on frequency self-locking according to a fourth embodiment of the present invention is shown;

[0027] Figure 5 The flowchart of the laser generating method based on frequency self-locking according to an embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0028] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of concepts of the present invention.

[0029] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0030] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0031] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0032] Figure 1 The structure of a laser generating device based on frequency self-locking according to the first embodiment of the present invention is schematically shown.

[0033] like Figure 1 As shown, a laser generating device based on frequency self-locking may include a local oscillator laser, an oscillation loop and a self-locking module.

[0034] The local oscillator laser is used to generate the laser signal.

[0035] The oscillation loop is used to generate a first oscillation radio frequency signal based on the laser signal. The oscillation loop includes a controller. The frequency of the oscillation radio frequency signal is adjusted by adjusting the state of the controller.

[0036] The self-locking module is used to perform frequency scanning on the laser and detect the power and frequency of the oscillating RF signal, and when the frequency of the oscillating RF signal reaches a preset frequency range, the frequency of the laser signal is locked by locking the frequency of the first oscillating RF signal.

[0037] In the embodiment of the present disclosure, the oscillating RF signal output by the oscillation loop is input to the automatic locking module for detecting the RF oscillation state of the oscillation loop and the phase-locking unit input in the self-locking module. The self-locking module outputs two signals to control the local oscillator laser and the controller in the oscillation loop respectively.

[0038] Figure 2 The structure of the self-locking module in the laser generating device based on frequency self-locking according to the second embodiment of the present invention is schematically shown.

[0039] like Figure 2 As shown, based on the above embodiment, the self-locking module of the laser generating device based on frequency self-locking in this embodiment may include: a microprocessor and a phase locking unit.

[0040] The microprocessor includes an input terminal, a first output terminal, a second output terminal, and a third output terminal; an oscillating radio frequency signal is received through the input terminal to detect the frequency of the oscillating radio frequency signal; the frequency of the oscillating radio frequency signal is adjusted by adjusting the state of the controller through the output signal of the first output terminal; a scanning voltage signal is output through the second output terminal to perform frequency scanning on the laser and an adjusting voltage is output to adjust the frequency of the laser signal output by the local oscillator laser; and the third output terminal communicates with a phase-locking module, so that the phase-locking module outputs a locking signal to lock the frequency of the first oscillating radio frequency signal to lock the frequency of the laser signal.

[0041] The self-locking process can be: the microprocessor outputs a scanning signal, the laser frequency is scanned through the second output terminal, and the oscillation RF signal state of the oscillation loop is detected through the input port. When the oscillation RF signal reaches the power threshold, the amplitude of the scanning voltage signal output at this time is recorded, and the frequency of the input signal is calculated and recorded at the same time. When the scanning voltage completes a scanning cycle, the corresponding relationship between the adjustment voltage of the local oscillator laser and the frequency of the oscillation RF signal can be obtained.

[0042] Since the oscillation frequency is not continuous, when the frequency of the oscillating RF signal does not overlap with the required frequency, the controller state is changed by adjusting the signal at the first output terminal. After the adjustment is completed, the local oscillator laser voltage scan is performed again. When it is detected that the frequency of the input oscillating RF signal reaches the set value range, the microprocessor communicates with the phase-locked loop to complete the phase-locking step, realize the locking of the oscillating RF signal, and complete the automatic locking of the frequency of the local oscillator laser.

[0043] Figure 3 The structure of a laser generating device based on frequency self-locking according to the third embodiment of the present invention is schematically shown.

[0044] like Figure 3 As shown, the oscillation loop in the frequency self-locking laser generating device of this embodiment includes: an optical phase modulator, an optical filter, a photodetector, a radio frequency amplifier, and a power divider.

[0045] The optical phase modulator is used to modulate the microwave signal onto the laser signal to obtain a modulated optical signal.

[0046] The optical filter is used to perform notch filtering on the modulated optical signal to obtain an optical signal after notch filtering.

[0047] The photoelectric detector is used to beat the optical signal after the notch filtering to obtain a second oscillation radio frequency signal.

[0048] The radio frequency amplifier is used to amplify the second oscillation radio frequency signal to obtain the first oscillation radio frequency signal.

[0049] The power divider is used to divide the first oscillation radio frequency signal into two first oscillation radio frequency signals with equal power, output one of which to the optical phase modulator and input the other to the microprocessor.

[0050] Figure 4 The structure of a laser generating device based on frequency self-locking according to a fourth embodiment of the present invention is schematically shown.

[0051] like Figure 4 As shown, in Figure 1-Figure 3 Based on the embodiment shown, the phase-locked unit of this embodiment includes a phase-locked loop or a combination of a mixer and a feedback controller. The controller includes a phase shifter or an adjustable delay line. A voltage adder can be used to input the output of the phase-locked loop and the output of the microprocessor into the local oscillator laser. The voltage adder can be replaced by a voltage biaser.

[0052] It should be noted that for details not included in this embodiment, please refer to the above embodiments and will not be repeated here.

[0053] Based on the above embodiment, the microprocessor can also be used to: after the frequency of the laser signal and the first oscillating RF signal are successfully locked, monitor the frequency and power of the oscillating RF signal through the input end. After the oscillation loop loses lock, lock the frequency of the first oscillating RF signal again to lock the frequency of the laser signal.

[0054] Based on the above embodiment, it further includes: an optical coupler, which is arranged between the output end of the local oscillator laser and the input end of the optical phase modulator, and is used to output the locked laser signal.

[0055] The optical filter can also serve as the output port of the locked laser signal.

[0056] Figure 5 The flowchart of the laser generating method based on frequency self-locking according to an embodiment of the present invention is schematically shown.

[0057] As shown in the figure, the laser generation method based on frequency self-locking may include:

[0058] A laser signal is generated by a local oscillator laser. A first oscillation radio frequency signal is generated based on the laser signal by an oscillation loop, and the oscillation loop includes a controller, and the frequency of the oscillation radio frequency signal is adjusted by adjusting the state of the controller. The laser is frequency scanned and the power and frequency of the oscillation radio frequency signal are detected by a self-locking module, and when the frequency of the oscillation radio frequency signal reaches a preset frequency range, the frequency of the laser signal is locked by locking the frequency of the first oscillation radio frequency signal. After the frequency of the laser signal is locked, the locked laser signal is output.

[0059] The automatic locking process of the method can be: the microprocessor outputs a scanning signal, performs a frequency scanning on the laser, and detects the oscillation RF signal state of the oscillation loop through the input port. When the oscillation RF signal reaches the power threshold, the amplitude of the scanning voltage signal output at this time is recorded, and the frequency of the input signal is calculated and recorded at the same time. When the scanning voltage completes a scanning cycle, the corresponding relationship between the adjustment voltage of the local oscillator laser and the frequency of the oscillation RF signal can be obtained.

[0060] Since the frequency of the oscillating RF signal is not continuous, when the frequency of the oscillating RF signal does not overlap with the required frequency, the phase of the oscillation loop is adjusted by adjusting the phase shifter through the first output terminal output signal. After the adjustment is completed, the local oscillator laser voltage is scanned again, and the local oscillator laser adjustment voltage corresponding to the optimal oscillating RF signal frequency is finally calculated, and this voltage value is output to the laser through the second output terminal. When it is detected that the input RF signal frequency reaches the set value range, the microprocessor sends a phase-locked instruction to the phase-locked loop to achieve the locking of the oscillating RF signal and complete the automatic frequency locking of the local oscillator laser.

[0061] It should be noted that for details not provided in the laser generating method based on frequency self-locking of this embodiment, please refer to the laser generating device based on frequency self-locking of the above embodiment, which will not be described again here.

[0062] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways, even if such combinations and / or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All of these combinations and / or combinations fall within the scope of the present invention.

[0063] The embodiments of the present invention are described above. However, these embodiments are only for the purpose of illustration, and are not intended to limit the scope of the present invention. Although each embodiment is described above, it does not mean that the measures in each embodiment cannot be used in combination. The scope of the present invention is defined by the attached claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A laser generating device based on frequency self-locking, characterized in that: include: A local oscillator laser, used to generate a laser signal; An oscillation loop, used to generate a first oscillation radio frequency signal based on the laser signal, the oscillation loop comprising a controller, and the frequency of the oscillation radio frequency signal is adjusted by adjusting the state of the controller; The self-locking module is used to perform frequency scanning on the laser and detect the power and frequency of the oscillating radio frequency signal, and when the frequency of the oscillating radio frequency signal reaches a preset frequency range, the frequency of the laser signal is locked by locking the frequency of the first oscillating radio frequency signal.

2. The device according to claim 1, characterized in that The self-locking module comprises: a microprocessor and a phase-locking unit; The microprocessor includes an input end, a first output end, a second output end, and a third output end; the oscillation radio frequency signal is received through the input end to detect the frequency of the oscillation radio frequency signal; the state of the controller is adjusted to adjust the frequency of the oscillation radio frequency signal through the output signal of the first output end; the scanning voltage signal is output through the second output end to scan the frequency of the laser and the adjustment voltage is output to adjust the frequency of the laser signal output by the local oscillator laser; the third output end communicates with the phase-locking module so that the phase-locking module outputs a locking signal to lock the frequency of the first oscillation radio frequency signal to lock the frequency of the laser signal.

3. The device according to claim 2, characterized in that The oscillation loop comprises: An optical phase modulator, used for modulating a microwave signal onto the laser signal to obtain a modulated optical signal; An optical filter, used for performing notch filtering on the modulated optical signal to obtain an optical signal after notch filtering; A photodetector, used for performing a beat frequency on the optical signal after the notch filtering to obtain a second oscillation radio frequency signal; a radio frequency amplifier, configured to amplify the second oscillation radio frequency signal to obtain the first oscillation radio frequency signal; A power divider is used to divide the first oscillation radio frequency signal into two first oscillation radio frequency signals with equal power, one of which is output to the optical phase modulator and the other is input to the microprocessor.

4. The device according to claim 2, characterized in that The self-locking module performs frequency scanning on the laser and detects the power and frequency of the oscillating radio frequency signal, including: When the power of the first oscillating radio frequency signal reaches a power threshold, recording the amplitude of the scanning voltage signal at this time, and calculating the frequency of the first oscillating radio frequency signal; After the scanning voltage completes a cycle of scanning, obtaining a corresponding relationship between the adjustment voltage of the local oscillator laser and the frequency of the first oscillation radio frequency signal; Based on the correspondence between the regulation voltage and the frequency of the first oscillation RF signal, the regulation voltage corresponding to the best first RF oscillation frequency is determined.

5. The device according to claim 3, characterized in that The self-locking module also includes: The analog-to-digital converter is arranged between the power divider and the microprocessor, and is used for converting the oscillating radio frequency signal into a digital signal and then inputting the digital signal into the microprocessor to detect the frequency of the first oscillating radio frequency signal.

6. The device according to claim 2, characterized in that The microprocessor is also used for: After the frequency of the laser signal and the first oscillation radio frequency signal are successfully locked, monitoring the frequency and power of the oscillation radio frequency signal through the input end; After the oscillation loop loses lock, the frequency of the first oscillation radio frequency signal is locked again to lock the frequency of the laser signal.

7. The device according to any one of claims 1 to 5, characterized in that: The phase-locked unit includes a phase-locked loop or a combination of a mixer and a feedback controller.

8. The device according to any one of claims 1 to 5, characterized in that: The controller includes a phase shifter or an adjustable delay line.

9. The device according to any one of claims 1 to 5, characterized in that: Also includes: The optical coupler is arranged between the output end of the local oscillator laser and the input end of the optical phase modulator, and is used for outputting the locked laser signal.

10. A laser generation method based on frequency self-locking, characterized in that: include: Generate a laser signal by using a local oscillator laser; generating a first oscillating radio frequency signal based on the laser signal through an oscillation loop, wherein the oscillation loop includes a controller, and the frequency of the oscillating radio frequency signal is adjusted by adjusting a state of the controller; Performing frequency scanning on the laser and detecting the power and frequency of the oscillating radio frequency signal through a self-locking module, and locking the frequency of the laser signal by locking the frequency of the first oscillating radio frequency signal when the frequency of the oscillating radio frequency signal reaches a preset frequency range; After the frequency of the laser signal is locked, the locked laser signal is output.

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