Frequency stabilized laser based on double-fiber interferometer

Abstract

The invention discloses a frequency stabilized laser based on a double-fiber interferometer. The frequency stabilized laser comprises a narrow linewidth laser, an acousto-optic frequency shifter, a 1 * 2 fiber splitter I, the double-fiber interferometer, a voltage-controlled oscillator and a control module, the output end of the narrow linewidth laser is connected with the input end of the acousto-optic frequency shifter, and the two input ends are connected with the second output end and the third output end of the control module respectively. The driving input end of the acousto-optic frequency shifter is connected with the output end of the voltage-controlled oscillator, and the output end of the acousto-optic frequency shifter is connected with the input end of the 1 * 2 optical fiber splitter I; one output end of the 1 * 2 optical fiber splitter I outputs a frequency-stabilized laser signal, and the other output end of the 1 * 2 optical fiber splitter I is connected with the input end of the double-optical-fiber interferometer; the output end of the double-fiber interferometer is connected with the input end of the control module; the first output end of the control module is connected with the voltage-controlled oscillator, and the second and third output ends are connected with the narrow linewidth laser. According to the invention, laser signal output with high precision and high frequency stability is realized, and the frequency stability of the laser is three to four orders of magnitude higher than that of a narrow linewidth laser.

Description

Technical Field

[0001] The invention belongs to the technical field of lasers, and in particular relates to a frequency-stabilized laser based on a dual-fiber interferometer. Background Art

[0002] Narrow linewidth lasers have good coherence performance and are widely used in lidar, optical instruments, and various fiber optic sensing technology fields. Existing commercial narrow linewidth lasers, such as narrow linewidth fiber lasers and narrow linewidth semiconductor lasers, can only control the laser frequency stability at the order of 10MHz@100s due to the influence of factors such as thermodynamic noise and environmental vibration noise in the resonant cavity. Laser frequency stabilization technology is required to suppress the frequency jitter and drift of the laser. Common laser frequency stabilization technology is based on phase-modulated optical heterodyne (PDH) technology, but the use of technical means such as gas molecule saturated absorption and ultra-stable cavity is not conducive to compact structure design, and the construction and use costs are high, making it difficult to promote and apply. However, in some precision measurement fields, the frequency stability requirements for narrow linewidth lasers are extremely high. Therefore, it is necessary to design a low-cost, high-frequency-stability frequency-stabilized laser to meet the needs of precision measurement fields. Summary of the Invention

[0003] The present invention provides a frequency-stabilized laser based on a dual-fiber interferometer to solve the problem of insufficient frequency stability of existing narrow-linewidth lasers.

[0004] To solve the above problems, the present invention is achieved through the following technical solutions:

[0005] A frequency-stabilized laser based on a dual-fiber interferometer, including a narrow-linewidth laser, an acousto-optic frequency shifter, a 1×2 fiber splitter I, a dual-fiber interferometer, a voltage-controlled oscillator, and a control module;

[0006] The laser output end of the narrow linewidth laser is connected to the input end of the acousto-optic frequency shifter, and the two electronic input ends of the narrow linewidth laser are respectively connected to the second and third output ends of the control module;

[0007] The input end of the acousto-optic frequency shifter is connected to the laser output end of the narrow linewidth laser, the frequency adjustment input end of the acousto-optic frequency shifter is the voltage input end of the voltage-controlled oscillator, and the output end of the acousto-optic frequency shifter is connected to the input end of the 1×2 optical fiber splitter I;

[0008] The input end of the 1×2 optical fiber splitter I is connected to the output end of the acousto-optic frequency shifter, one of the output ends of the 1×2 optical fiber splitter I outputs a frequency-stabilized laser signal, and the other output end of the 1×2 optical fiber splitter I is connected to the input end of the dual-fiber interferometer;

[0009] The input end of the dual-fiber interferometer is connected to one output end of the 1×2 fiber splitter I. Interferometer I and interferometer II of the dual-fiber interferometer each output two interference signals, which are respectively connected to the input ends of the two photoelectric detection groups PD1, PD2 and PD3, PD4 of the control module;

[0010] The photoelectric detection input end of the control module is connected to the optical fiber output end detected by the dual-fiber interferometer, the first output end of the control module is connected to the voltage-controlled oscillator, and the second output end and the third output end of the control module are both connected to the narrow linewidth laser;

[0011] Both fiber interferometers are Michelson fiber interferometers, each comprising a 3×3 fiber coupler, a measurement fiber, and two Faraday magnetic rotator mirrors. The left side of the 3×3 fiber coupler includes at least three ports, one of which forms the input of the fiber interferometer, and the other two ports, connected to photodetectors, form the two outputs of the fiber interferometer. The right side of the 3×3 fiber coupler includes at least two ports, one of which is connected to one Faraday magnetic rotator mirror via a measurement fiber, and the other port is directly connected to the other Faraday magnetic rotator mirror. The measurement fibers of the two fiber interferometers have different temperature delay coefficients.

[0012] The two fiber interferometer measurement arms work in the same environment. Without considering the influence of vibration, the phase changes of interferometer I and interferometer II caused by temperature change and narrow linewidth laser frequency drift are:

[0013]

[0014] Among them, the temperature drift coefficients of the optical fibers of the two fiber interferometer measurement arms are different, which are:

[0015]

[0016] When L1=L2=L, that is, the arm length difference of the dual-fiber interferometer is equal, the frequency drift of the narrow linewidth laser is:

[0017]

[0018] Wherein, A represents the ratio of the temperature delay coefficient of the measuring optical fiber of the first Michelson fiber interferometer to that of the second Michelson fiber interferometer, and A≠1; L1 represents the length difference between the measuring arm and the reference arm of the first Michelson fiber interferometer, and L2 represents the length difference between the measuring arm and the reference arm of the second Michelson fiber interferometer; N1 represents the optical fiber phase drift detection value of the first Michelson fiber interferometer, and N2 represents the optical fiber phase drift detection value of the second Michelson fiber interferometer; n1 is the refractive index of the measuring optical fiber in interferometer I, n2 is the refractive index of the measuring optical fiber in interferometer II, c is the speed of light in vacuum, t is time, and f is the laser frequency.

[0019] As a further improvement to the above solution:

[0020] Preferably, the narrow linewidth laser is a single-frequency fiber laser; the laser output end of the narrow linewidth laser provides a narrow linewidth laser seed source for the frequency-stabilized laser, which is connected to an acousto-optic frequency shifter, and the driver frequency of the acousto-optic frequency shifter is adjusted by a voltage-controlled oscillator, thereby finely adjusting the output signal frequency of the narrow linewidth laser, and the adjustment voltage of the voltage-controlled oscillator is adjusted by connecting to the first output end of the control module; the first electronic input end of the narrow linewidth laser is connected to the second output end of the control module to adjust the PZT voltage, thereby adjusting the output signal frequency of the narrow linewidth laser in a larger range; the second electronic input end of the narrow linewidth laser is connected to the third output end of the control module to adjust the TEC temperature, thereby adjusting the output signal frequency of the narrow linewidth laser in a larger range.

[0021] Preferably, the narrow-linewidth laser is a single-frequency semiconductor laser; the laser output end of the narrow-linewidth laser provides a narrow-linewidth laser seed source for the frequency-stabilized laser, which is connected to an acousto-optic frequency shifter, and the driver frequency of the acousto-optic frequency shifter is adjusted by a voltage-controlled oscillator, thereby finely adjusting the output signal frequency of the narrow-linewidth laser, and the adjustment voltage of the voltage-controlled oscillator is adjusted by connecting to the first output end of the control module; the first electronic input end of the narrow-linewidth laser is connected to the second output end of the control module to finely adjust the narrow-linewidth laser current, thereby adjusting the output signal frequency of the narrow-linewidth laser in a larger range; the second electronic input end of the narrow-linewidth laser is connected to the third output end of the control module to adjust the TEC temperature, thereby adjusting the output signal frequency of the narrow-linewidth laser in a larger range.

[0022] Preferably, the control module includes a demodulation operation part and a control part. The demodulation operation part uses the dual-fiber interferometer output interference signal to demodulate the narrow linewidth laser frequency drift, and then converts it into a control signal to the control part; the control part performs compensation control on the narrow linewidth laser according to the control signal obtained from the demodulation operation module. When the frequency offset of the AOM reaches the adjustment step of the PZT, the PZT adjusts the laser frequency offset in the same direction, thereby releasing the range of the AOM; when the frequency offset of the PZT reaches the adjustment step of the TEC, the TEC adjusts the laser frequency offset in the same direction, thereby releasing the range of the PZT.

[0023] Preferably, the control module includes a demodulation operation part and a control part. The demodulation operation part uses the interference signal output by the dual-fiber interferometer to demodulate the frequency drift of the narrow-linewidth laser, and then converts it into a control signal to the control part; the control part performs compensation control on the narrow-linewidth laser according to the control signal obtained from the demodulation operation module. When the frequency offset of the AOM reaches the adjustment step of the current regulation, the laser frequency offset is adjusted in the same direction by the current regulation, thereby releasing the range of the AOM; when the frequency offset of the current regulation reaches the adjustment step of the TEC, the laser frequency offset is adjusted in the same direction by the TEC, thereby releasing the range of the current regulation.

[0024] Preferably, the ratio A of the temperature delay coefficients of the measuring optical fibers of the first Michelson fiber interferometer and the second Michelson fiber interferometer is a function of the temperature T, and A(T)≠1; the method for measuring A(T) is as follows: an ultra-stable laser having a frequency stability more than one order of magnitude less than that of the frequency-stabilized laser is connected to the dual-fiber interferometer, the operating temperature of the dual-fiber interferometer is slowly changed, and the current operating temperature value T is measured, and the phase changes dN1 / dT and dN2 / dT of the two fiber interferometers are simultaneously detected, and the phase change caused by the frequency drift of the ultra-stable laser is ignored.

[0025]

[0026] Available

[0027]

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] 1. The frequency-stabilized laser based on the dual-fiber interferometer of this invention can achieve laser frequency stability in the kHz range, supporting its use in the field of precision measurement.

[0030] 2. The frequency-stabilized laser based on the dual-fiber interferometer of the present invention can operate continuously and stably in an operating environment with a wide temperature variation range, and can meet the requirements of compact packaging volume and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a frequency-stabilized laser based on a dual-fiber interferometer.

[0032] Figure 2 Schematic diagram of the optical structure of a dual-fiber interferometer.

[0033] Figure 3 A detailed schematic diagram of the control module. DETAILED DESCRIPTION

[0034] In order to make the objects and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0035] like Figure 1 As shown, the present invention is a frequency-stabilized laser based on a dual-fiber interferometer, comprising a narrow-linewidth laser, an acousto-optic frequency shifter, a 1×2 fiber splitter I, a dual-fiber interferometer, a voltage-controlled oscillator, and a control module. The temperature delay coefficient (unit: ps / (km·℃)) of the measuring fiber Ⅰ on the measuring arm of the fiber interferometer Ⅰ is different from that of the measuring fiber Ⅱ on the measuring arm of the fiber interferometer Ⅱ. The narrow-linewidth laser emits a laser signal and connects to the acousto-optic frequency shifter. The signal adjusted by the acousto-optic frequency shifter is connected to the 1×2 fiber splitter I. One output end of the 1×2 fiber splitter I serves as the signal output of the frequency-stabilized laser, and the other output end is connected to the dual-fiber interferometer. In the dual-fiber interferometer, the laser signal to be detected output by the 1×2 fiber splitter I is connected to the 1 ×2 fiber splitter II, the two laser signals to be detected output by 1×2 fiber splitter II enter interferometer I and interferometer II, and the two interference signals output by interferometer I and interferometer II are connected to the input ends of the two photoelectric detection groups PD1 and PD2 and PD3 and PD4 of the control module respectively for fiber phase drift detection. The photoelectric detection input end of the control module is connected to the optical fiber output end of the dual-fiber interferometer detection. The first output end of the control module is connected to the voltage-controlled oscillator, and the second and third output ends of the control module are both connected to the narrow linewidth laser; Figure 3 As shown, the control module includes a demodulation operation part and a control part. The demodulation operation part uses the phase drift detection results of two fiber interferometers to calculate the laser frequency drift amount caused by the narrow linewidth laser frequency drift; the laser frequency drift amount caused by the narrow linewidth laser frequency drift is used by the control part in the control module to feedback and compensate for the laser frequency drift.

[0036] As a preferred embodiment, the narrow-linewidth laser is a single-frequency fiber laser, and the fiber output end of the narrow-linewidth laser provides a narrow-linewidth laser seed source for the frequency-stabilized laser, which is connected to an acousto-optic frequency shifter. The driver frequency of the acousto-optic frequency shifter is adjusted by a voltage-controlled oscillator, thereby finely adjusting the output signal frequency of the narrow-linewidth laser. The adjustment voltage of the voltage-controlled oscillator is adjusted by connecting to the first output end of the control module; the first electronic input end of the narrow-linewidth laser is connected to the second output end of the control module to adjust the PZT voltage, thereby adjusting the output signal frequency of the narrow-linewidth laser in a larger range; the second electronic input end of the narrow-linewidth laser is connected to the third output end of the control module to adjust the TEC temperature, thereby adjusting the output signal frequency of the narrow-linewidth laser in a larger range. In this embodiment, the demodulation operation part of the control module uses the dual-fiber interferometer output interference signal to demodulate the narrow linewidth laser frequency drift, and then converts it into a control signal to the control part; the control part performs compensation control on the narrow linewidth laser according to the control signal obtained from the demodulation operation module. When the frequency offset of the AOM reaches the adjustment step of the PZT, the PZT adjusts the laser frequency offset in the same direction, thereby releasing the range of the AOM; when the frequency offset of the PZT reaches the adjustment step of the TEC, the TEC adjusts the laser frequency offset in the same direction, thereby releasing the range of the PZT.

[0037] As another preferred embodiment, the narrow-linewidth laser is a single-frequency semiconductor laser; the optical fiber output end of the narrow-linewidth laser provides a narrow-linewidth laser seed source for the frequency-stabilized laser, which is connected to an acousto-optic frequency shifter, and the driver frequency of the acousto-optic frequency shifter is adjusted by a voltage-controlled oscillator, thereby finely adjusting the output signal frequency of the narrow-linewidth laser, and the adjustment voltage of the voltage-controlled oscillator is adjusted by connecting to the first output end of the control module; the first electronic input end of the narrow-linewidth laser is connected to the second output end of the control module to finely adjust the narrow-linewidth laser current, thereby adjusting the output signal frequency of the narrow-linewidth laser over a larger range; the second electronic input end of the narrow-linewidth laser is connected to the third output end of the control module to adjust the TEC temperature, thereby adjusting the output signal frequency of the narrow-linewidth laser over a larger range. In this embodiment, the demodulation operation part of the control module uses the frequency drift of the narrow linewidth laser demodulated by the interference signal output by the dual-fiber interferometer to convert it into a control signal and then provide it to the control part; the control part performs compensation control on the narrow linewidth laser according to the control signal obtained from the demodulation operation module. When the frequency offset of the AOM reaches the adjustment step of the current regulation, the laser frequency offset is adjusted in the same direction by the current regulation, thereby releasing the range of the AOM; when the frequency offset of the current regulation reaches the adjustment step of the TEC, the laser frequency offset is adjusted in the same direction by the TEC, thereby releasing the range of the current regulation.

[0038] The technical parameters of AOM are as follows: adjustment resolution ≤ 1kHz, adjustment range ≥ ±20MHz, adjustment bandwidth ≥ 1kHz, response time ≤ 0.1ms.

[0039] The technical parameters of PZT or current regulation are as follows: regulation resolution ≤ 100kHz, regulation range ≥ ±300MHz, regulation bandwidth ≥ 1kHz, response time ≤ 0.1ms.

[0040] The technical parameters of TEC are as follows: adjustment resolution ≤ 50 MHz, adjustment range ≥ 5 GHz, adjustment bandwidth approximately 1 Hz, and response time ≤ 0.1 s.

[0041] The optical fiber input end of the acousto-optic frequency shifter is connected to the output light source of the narrow linewidth laser. The frequency adjustment input end of the acousto-optic frequency shifter is the voltage input end of the voltage-controlled oscillator. The frequency electrical signal generated by the voltage-controlled oscillator is amplified by radio frequency to drive the acousto-optic frequency shifter to shift the frequency, thereby finely compensating for the frequency drift of the narrow linewidth laser. The output end of the acousto-optic frequency shifter is connected to the input end of the 1×2 optical fiber splitter I.

[0042] The input end of the 1×2 optical fiber splitter I is connected to the output end of the acousto-optic frequency shifter, one of the output ends of the 1×2 optical fiber splitter I outputs a frequency-stabilized laser signal, and the other output end of the 1×2 optical fiber splitter I is connected to the input end of the dual-fiber interferometer.

[0043] like Figure 1 As shown, the input end of the dual-fiber interferometer is connected to one output end of the 1×2 fiber splitter I, and the output end of the dual-fiber interferometer is connected to the photoelectric detection input end of the control module. Figure 2 As shown, both fiber interferometers are Michelson interferometers, each consisting of a 3×3 fiber coupler, a measurement fiber, and two Faraday magnetic rotator mirrors. The left side of the 3×3 fiber coupler includes at least three ports, one of which forms the input of the fiber interferometer, and the other two ports, connected to photodetectors, form the two outputs of the fiber interferometer. The right side of the 3×3 fiber coupler includes at least two ports, one of which is connected to one Faraday magnetic rotator mirror via a measurement fiber, and the other port is directly connected to the other Faraday magnetic rotator mirror. The measurement fibers of the two fiber interferometers have different temperature delay coefficients.

[0044] The two fiber interferometer measurement arms work in the same environment. Without considering the influence of vibration, the phase changes of fiber interferometer I and fiber interferometer II caused by temperature change and laser frequency drift are:

[0045]

[0046] Among them, the temperature drift coefficients of the optical fibers of the two fiber interferometer measurement arms are different, which are:

[0047]

[0048] When L1=L2=L, that is, the arm length difference of the dual-fiber interferometer is equal, the frequency drift of the laser is:

[0049]

[0050] Wherein, A represents the ratio of the temperature delay coefficient of the measuring optical fiber of the first Michelson fiber interferometer to that of the second Michelson fiber interferometer, and A≠1; L1 represents the length difference between the measuring arm and the reference arm of the first Michelson fiber interferometer, and L2 represents the length difference between the measuring arm and the reference arm of the second Michelson fiber interferometer; N1 represents the optical fiber phase drift detection value of the first Michelson fiber interferometer, and N2 represents the optical fiber phase drift detection value of the second Michelson fiber interferometer; n1 is the refractive index of the measuring optical fiber in fiber interferometer I, n2 is the refractive index of the measuring optical fiber in fiber interferometer II, c is the speed of light in vacuum, t is time, and f is the laser frequency.

[0051] The ratio A of the temperature delay coefficients of the measuring fibers of the first Michelson fiber interferometer and the second Michelson fiber interferometer is a function of the temperature T, and A(T)≠1. The measurement method of A(T) is as follows: an ultra-stable laser whose frequency stability is more than one order of magnitude less than that of the stabilized laser is connected to the dual-fiber interferometer, the operating temperature of the dual-fiber interferometer is slowly changed, and the current operating temperature value T is measured. The phase changes dN1 / dT and dN2 / dT of the two fiber interferometers are detected simultaneously, and the phase change caused by the frequency drift of the ultra-stable laser is ignored.

[0052]

[0053] Available

[0054]

[0055] The above embodiments are only specific examples to further illustrate the purpose, technical solutions and beneficial effects of the present invention, and the present invention is not limited thereto. Any modifications, equivalent replacements, improvements, etc. made within the scope of the disclosure of the present invention are included in the scope of protection of the present invention.

Claims

1. Frequency-stabilized laser based on dual-fiber interferometer, characterized by: It includes narrow linewidth laser, acousto-optic frequency shifter, 1×2 fiber splitter I, dual-fiber interferometer, voltage-controlled oscillator and control module; The laser output end of the narrow linewidth laser is connected to the input end of the acousto-optic frequency shifter, and the two electronic input ends of the narrow linewidth laser are respectively connected to the second and third output ends of the control module; The input end of the acousto-optic frequency shifter is connected to the output end of the narrow linewidth laser, the frequency adjustment input end of the acousto-optic frequency shifter is the voltage input end of the voltage-controlled oscillator, and the output end of the acousto-optic frequency shifter is connected to the input end of the 1×2 optical fiber splitter I; The input end of the 1×2 optical fiber splitter I is connected to the output end of the acousto-optic frequency shifter, one of the output ends of the 1×2 optical fiber splitter I outputs a frequency-stabilized laser signal, and the other output end of the 1×2 optical fiber splitter I is connected to the input end of the dual-fiber interferometer; The input end of the dual-fiber interferometer is connected to one output end of the 1×2 fiber splitter I. The two output ends of the 1×2 fiber splitter II in the dual-fiber interferometer are connected to interferometer I and interferometer II respectively. Interferometer I and interferometer II each output two interference signals, which are respectively connected to the input ends of the two photoelectric detection groups PD1 and PD2 and PD3 and PD4 of the control module; The photoelectric detection input end of the control module is connected to the optical fiber output end detected by the dual-fiber interferometer, the first output end of the control module is connected to the voltage-controlled oscillator, and the second output end and the third output end of the control module are both connected to the narrow linewidth laser; Both fiber interferometers are Michelson fiber interferometers, each comprising a 3×3 fiber coupler, a measurement fiber, and two Faraday magnetic rotator mirrors. The left side of the 3×3 fiber coupler includes at least three ports, one of which forms the input of the fiber interferometer, and the other two ports, connected to photodetectors, form the two outputs of the fiber interferometer. The right side of the 3×3 fiber coupler includes at least two ports, one of which is connected to one Faraday magnetic rotator mirror via a measurement fiber, and the other port is directly connected to the other Faraday magnetic rotator mirror. The measurement fibers of the two fiber interferometers have different temperature delay coefficients. The two fiber interferometer measurement arms work in the same environment. Without considering the influence of vibration, the phase changes of interferometer I and interferometer II caused by temperature change and narrow linewidth laser frequency drift are: Among them, the temperature drift coefficients of the optical fibers of the two fiber interferometer measurement arms are different, which are: When L1=L2=L, that is, the arm length difference of the dual-fiber interferometer is equal, the frequency drift of the narrow linewidth laser is: Wherein, A represents the ratio of the temperature delay coefficient of the measuring optical fiber of the first Michelson fiber interferometer to that of the second Michelson fiber interferometer, and A≠1; L1 represents the length difference between the measuring arm and the reference arm of the first Michelson fiber interferometer, and L2 represents the length difference between the measuring arm and the reference arm of the second Michelson fiber interferometer; N1 represents the optical fiber phase drift detection value of the first Michelson fiber interferometer, and N2 represents the optical fiber phase drift detection value of the second Michelson fiber interferometer; n1 is the refractive index of the measuring optical fiber in interferometer I, n2 is the refractive index of the measuring optical fiber in interferometer II, c is the speed of light in vacuum, t is time, and f is the laser frequency.

2. The frequency-stabilized laser based on a dual-fiber interferometer according to claim 1, characterized in that: The narrow linewidth laser is a single-frequency fiber laser; the fiber output end of the narrow linewidth laser provides a narrow linewidth laser seed source for the frequency-stabilized laser, which is connected to an acousto-optic frequency shifter. The voltage-controlled oscillator adjusts the driver frequency of the acousto-optic frequency shifter, thereby finely adjusting the output signal frequency of the narrow linewidth laser. The adjustment voltage of the voltage-controlled oscillator is adjusted by connecting to the first output end of the control module; the first electronic input end of the narrow linewidth laser is connected to the second output end of the control module to adjust the PZT voltage, thereby adjusting the output signal frequency of the narrow linewidth laser over a larger range; the second electronic input end of the narrow linewidth laser is connected to the third output end of the control module to adjust the TEC temperature, thereby adjusting the output signal frequency of the narrow linewidth laser over a larger range.

3. The frequency-stabilized laser based on a dual-fiber interferometer according to claim 1, characterized in that: The narrow-linewidth laser is a single-frequency semiconductor laser; the optical fiber output end of the narrow-linewidth laser provides a narrow-linewidth laser seed source for the frequency-stabilized laser, which is connected to an acousto-optic frequency shifter. The voltage-controlled oscillator adjusts the driver frequency of the acousto-optic frequency shifter, thereby finely adjusting the output signal frequency of the narrow-linewidth laser. The adjustment voltage of the voltage-controlled oscillator is adjusted by connecting to the first output end of the control module; the first electronic input end of the narrow-linewidth laser is connected to the second output end of the control module to finely adjust the narrow-linewidth laser current, thereby adjusting the output signal frequency of the narrow-linewidth laser in a larger range; the second electronic input end of the narrow-linewidth laser is connected to the third output end of the control module to adjust the TEC temperature, thereby adjusting the output signal frequency of the narrow-linewidth laser in a larger range.

4. The frequency-stabilized laser based on a dual-fiber interferometer according to claim 1 or 2, characterized in that: The control module includes a demodulation operation part and a control part. The demodulation operation part uses the interference signal output by the dual-fiber interferometer to demodulate the frequency drift of the narrow-linewidth laser, and then converts it into a control signal to the control part; the control part compensates and controls the narrow-linewidth laser according to the control signal obtained from the demodulation operation module. When the frequency offset of the AOM reaches the adjustment step of the PZT, the PZT adjusts the laser frequency offset in the same direction, thereby releasing the range of the AOM; when the frequency offset of the PZT reaches the adjustment step of the TEC, the TEC adjusts the laser frequency offset in the same direction, thereby releasing the range of the PZT.

5. The frequency-stabilized laser based on a dual-fiber interferometer according to claim 1 or 3, characterized in that: The control module includes a demodulation operation part and a control part. The demodulation operation part uses the interference signal output by the dual-fiber interferometer to demodulate the frequency drift of the narrow-linewidth laser, and then converts it into a control signal to the control part; the control part compensates and controls the narrow-linewidth laser according to the control signal obtained from the demodulation operation module. When the frequency offset of the AOM reaches the adjustment step of the current regulation, the laser frequency offset is adjusted in the same direction by the current regulation, thereby releasing the range of the AOM; when the frequency offset of the current regulation reaches the adjustment step of the TEC, the laser frequency offset is adjusted in the same direction by the TEC, thereby releasing the range of the current regulation.

6. The frequency-stabilized laser based on a dual-fiber interferometer according to claim 1, characterized in that: The ratio A of the temperature delay coefficients of the measuring fibers of the first Michelson fiber interferometer and the second Michelson fiber interferometer is a function of the temperature T, and A(T)≠1. The measurement method of A(T) is as follows: an ultra-stable laser whose frequency stability is more than one order of magnitude less than that of the stabilized laser is connected to the dual-fiber interferometer, the operating temperature of the dual-fiber interferometer is slowly changed, and the current operating temperature value T is measured. The phase changes dN1 / dT and dN2 / dT of the two fiber interferometers are detected simultaneously, and the phase change caused by the frequency drift of the ultra-stable laser is ignored. Available

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