All-fiber laser wavelength detection device and method

Abstract

The present application discloses an all-fiber laser wavelength detection device and method, the device includes: a reference light generator, a light input unit to be measured, a first coupler, an optical path adjustment unit, a reference arm optical fiber, an interference arm optical fiber, a second coupler, a band-stop unit, a band-pass unit and a signal processing unit; the reference light generator generates a reference laser, and the light input unit to be measured obtains the laser to be measured; the first coupler splits the reference laser and the laser to be measured into the reference arm optical fiber and the interference arm optical fiber to obtain the reference arm signal and the interference arm signal; the second coupler receives the mixed light signal formed by the reference arm signal and the interference arm signal; the band-stop unit and the band-pass unit perform band-stop and band-pass filtering on the mixed light signal to obtain the interference light signal of the laser to be measured and the interference light signal of the reference laser, and the wavelength of the laser to be measured is determined by the signal processing unit. The present invention can avoid the interference of the space environment in the laser wavelength detection, save the cumbersome dimming process, and improve the anti-interference ability.

Description

Technical Field

[0001] The invention relates to the technical field of laser wavelength measurement, and in particular to an all-fiber laser wavelength detection device and method. Background Art

[0002] With the birth of lasers, laser-based measurement technology has begun to play an increasingly important role in metrology, information science, communications, astronomy and other fields. As a measurement reference value, laser wavelength has been widely used in the measurement of displacement, flatness, roughness, vibration, gravity acceleration, verticality, etc. It is an important parameter in the fields of precision machining, precision machinery manufacturing and microelectronics. Therefore, accurately measuring laser wavelength can not only ensure the accuracy of laser measurement, but also is the key technology for value traceability.

[0003] The existing mainstream laser wavelength measurement method generally uses a Michelson interferometer or a Fizeau interferometer with an optical path difference of more than ten centimeters. This method has high measurement accuracy, but because the laser needs to be transmitted through space, it is easily disturbed by the environment, and the laser needs to be tuned by a variety of optical components such as spectroscopes and reflectors during transmission. This puts higher requirements on the finish of each optical component and the adjustment accuracy of the position and angle between components, and also leads to poor vibration resistance and low anti-pollution level of the entire system.

[0004] Therefore, it is necessary to design a new laser wavelength measurement device and method to solve the problems of high dimming difficulty and weak anti-interference performance in the existing laser wavelength measurement. Summary of the invention

[0005] In view of this, it is necessary to provide an all-fiber laser wavelength detection device and method to solve the problems of high dimming difficulty, weak vibration resistance and poor environmental pollution resistance in existing laser wavelength measurement devices.

[0006] In order to solve the above problems, the present invention provides an all-fiber laser wavelength detection device, comprising: a reference light generator, a light input unit to be measured, a first coupler, an optical path adjustment unit, a reference arm optical fiber, an interference arm optical fiber, a second coupler, a band-stop unit, a band-pass unit and a signal processing unit;

[0007] The reference light generator is used to generate reference laser light;

[0008] The light input unit to be measured is used to obtain the laser to be measured;

[0009] The first coupler is used to split the reference laser and the laser to be measured into the reference arm optical fiber and the interferometer arm optical fiber respectively, so as to obtain a reference arm signal and an interferometer arm signal; the reference arm optical fiber and the interferometer arm optical fiber are matched with each other;

[0010] The optical path adjustment unit is used to make the reference arm signal and the interference arm signal produce a preset optical path difference;

[0011] The second coupler is used to receive a mixed optical signal formed by the reference arm signal and the interference arm signal, and input the mixed optical signal into the band-stop unit and the band-pass unit;

[0012] The band-stop unit is used to perform band-stop filtering on the mixed optical signal to obtain a laser interference optical signal to be measured;

[0013] The bandpass unit is used to perform bandpass filtering on the mixed optical signal to obtain a reference laser interference optical signal;

[0014] The signal processing unit is used to perform photoelectric conversion on the laser interference light signal to be measured and the reference laser interference light signal to obtain a laser detection signal to be measured and a reference laser interference detection signal, and determine the wavelength of the laser to be measured based on the reference laser detection signal and the laser detection signal to be measured.

[0015] Further, the signal processing unit includes a photoelectric conversion module, an analog-to-digital conversion module and a data analysis module;

[0016] The photoelectric conversion module is used to convert the laser interference light signal to be measured and the reference laser interference light signal into a laser detection signal to be measured and a reference laser interference detection signal respectively;

[0017] The analog-to-digital conversion module is used to convert the laser detection signal to be measured and the reference laser interference detection signal into digital signals;

[0018] The data analysis module is used to collect and analyze the laser detection signal to be measured and the reference laser interference detection signal converted into digital signals, and determine the wavelength of the laser to be measured.

[0019] Furthermore, the reference light generator is a helium-neon laser generator.

[0020] Furthermore, the first coupler and the second coupler are both 2*2 optical fiber couplers.

[0021] Furthermore, the optical path adjustment unit includes piezoelectric ceramics, a piezoelectric drive module and a voltage control module; the interference arm optical fiber is wound around the piezoelectric ceramics;

[0022] The voltage control module is used to send a driving signal to the piezoelectric driving module;

[0023] The piezoelectric driving module is used to drive and control the piezoelectric ceramic according to the driving signal;

[0024] The piezoelectric ceramic is used to produce a diameter change under the control of the piezoelectric driving module, so that the reference arm signal and the interference arm signal produce a preset optical path difference.

[0025] Further, the band-stop unit includes a band-stop filter;

[0026] The band-stop filter is used to filter out the interference light signal of the reference light in the mixed light signal to obtain the laser interference light signal to be measured.

[0027] Further, the bandpass unit includes a bandpass filter;

[0028] The bandpass filter is used to separate the interference light signal of the reference light from the mixed light signal to obtain the reference laser interference light signal.

[0029] Furthermore, the reference arm optical fiber and the interference arm optical fiber are single-mode optical fibers or hollow-core optical fibers.

[0030] Furthermore, the data analysis module includes an FPGA processor.

[0031] The present invention also provides an all-fiber laser wavelength detection method, which uses the all-fiber laser wavelength detection device described in any of the above technical solutions, including:

[0032] Generate reference laser light through the reference light generator, and obtain the laser light to be measured through the light input unit to be measured;

[0033] The reference laser and the laser to be measured are respectively split into the reference arm optical fiber and the interference arm optical fiber by the first coupler to obtain a reference arm signal and an interference arm signal; the optical path adjustment unit causes the reference arm signal and the interference arm signal to generate a preset optical path difference;

[0034] The mixed optical signal formed by the reference arm signal and the interference arm signal is received by a second coupler, and the mixed optical signal is input into the band-stop unit and the band-pass unit; the mixed optical signal is subjected to band-stop filtering and band-pass filtering respectively by the band-stop unit and the band-pass unit to obtain a laser interference optical signal to be measured and a reference laser interference optical signal;

[0035] The signal processing unit performs photoelectric conversion on the laser interference light signal to be measured and the reference laser interference light signal to obtain a laser detection signal to be measured and a reference laser interference detection signal, and determines the wavelength of the laser to be measured based on the reference laser detection signal and the laser detection signal to be measured.

[0036] Compared with the prior art, the beneficial effects of the present invention include: first, a reference laser is generated by a reference light generator, and the laser to be measured is obtained by a light input unit to be measured; second, a reference arm signal and an interference arm signal are obtained by using a reference arm optical fiber and an interference arm optical fiber; third, a mixed optical signal formed by the reference arm signal and the interference arm signal is subjected to bandpass filtering and bandstop filtering to obtain a laser interference light signal to be measured and a reference laser interference light signal; finally, the laser interference light signal to be measured and the reference laser interference light signal are subjected to photoelectric conversion, and the wavelength of the laser to be measured is determined according to the reference laser detection signal and the laser detection signal to be measured. In the device of the present invention, both the reference light and the light to be measured are transmitted in the optical fiber, and the generation environment of the interference light is transferred to the inside of the optical fiber, thereby avoiding the interference of the external environment on the optical path; the use of optical fiber to build the interference optical path greatly simplifies the complexity of the optical path adjustment, omitting the components such as the reflector and the spectroscope in the traditional optical wavelength meter, and also optimizes the cumbersome adjustment process that needs to consider the position and angle of each component when building the traditional optical path; the structure of the device is more modular, and the type of optical fiber can be adjusted and replaced according to the specific measurement requirements, which can meet the detection needs of different types of lasers. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic structural diagram of an embodiment of an all-fiber laser wavelength detection device provided by the present invention;

[0038] Figure 2 A schematic diagram of the structure of an embodiment of a signal processing unit provided by the present invention;

[0039] Figure 3 A schematic structural diagram of an embodiment of an optical path adjustment unit provided by the present invention;

[0040] Figure 4 A schematic structural diagram of another embodiment of an all-fiber laser wavelength detection device provided by the present invention;

[0041] Figure 5 A schematic flow chart of an embodiment of an all-fiber laser wavelength detection method provided by the present invention. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0043] Before describing the embodiments, the current status of laser wavelength measurement and the design concept of the present invention are first explained.

[0044] In the existing technology, the measurement of laser wavelength is usually carried out using Michelson interferometer or Fizeau interferometer. Such methods require spatial transmission and are therefore easily affected by environmental interference. The entire system has poor vibration resistance and low anti-pollution level.

[0045] In order to improve the anti-interference ability of the wavelength measurement process, eliminate the cumbersome dimming process, and simplify the interference light path, the present invention transfers the generation environment of the interference light to the inside of the optical fiber through all-optical fiber transmission, thereby avoiding the interference of the external environment on the optical path and simplifying the complexity of the optical path adjustment.

[0046] The embodiment of the present invention provides an all-fiber laser wavelength detection device, such as Figure 1 As shown, Figure 1 1 is a structural diagram of the all-fiber laser wavelength detection device 100, comprising: a reference light generator 101, a light input unit 102 to be measured, a first coupler 103, an optical path adjustment unit 104, a reference arm optical fiber 106, an interference arm optical fiber 105, a second coupler 107, a band-stop unit 109, a band-pass unit 108 and a signal processing unit 110;

[0047] The reference light generator 101 is used to generate reference laser light;

[0048] The measured light input unit 102 is used to obtain the measured laser;

[0049] The first coupler 103 is used to split the reference laser and the laser to be measured into the reference arm optical fiber 106 and the interferometer arm optical fiber 105 respectively, to obtain a reference arm signal and an interferometer arm signal; the reference arm optical fiber 106 and the interferometer arm optical fiber 105 are matched with each other;

[0050] The optical path adjustment unit 104 is used to make the reference arm signal and the interference arm signal generate a preset optical path difference;

[0051] The second coupler 107 is used to receive a mixed optical signal formed by the reference arm signal and the interference arm signal, and input the mixed optical signal into the band-stop unit 109 and the band-pass unit 108;

[0052] The band-stop unit 109 is used to perform band-stop filtering on the mixed optical signal to obtain a laser interference optical signal to be measured;

[0053] The bandpass unit 108 is used to perform bandpass filtering on the mixed optical signal to obtain a reference laser interference optical signal;

[0054] The signal processing unit 110 is used to perform photoelectric conversion on the laser interference light signal to be measured and the reference laser interference light signal to obtain a laser detection signal to be measured and a reference laser interference detection signal, and determine the wavelength of the laser to be measured based on the reference laser detection signal and the laser detection signal to be measured.

[0055] As a preferred embodiment, Figure 2 As shown, the signal processing unit 110 includes a photoelectric conversion module 201, an analog-to-digital conversion module 202 and a data analysis module 203;

[0056] The photoelectric conversion module 201 is used to convert the laser interference light signal to be measured and the reference laser interference light signal into a laser detection signal to be measured and a reference laser interference detection signal respectively;

[0057] The analog-to-digital conversion module 202 is used to convert the laser detection signal to be measured and the reference laser interference detection signal into digital signals;

[0058] The data analysis module 203 is used to collect and analyze the laser detection signal to be measured and the reference laser interference detection signal converted into digital signals, and determine the wavelength of the laser to be measured.

[0059] Since the He-Ne laser is easy to manufacture, has low cost and high reliability, as a preferred embodiment, the reference light generator 101 is a He-Ne laser generator.

[0060] Specifically, the wavelength of the reference laser generated by the helium-neon laser generator is 632.8 nm.

[0061] As a preferred embodiment, the first coupler 103 and the second coupler 107 are both 2*2 optical fiber couplers.

[0062] As a specific embodiment, the splitting ratio of the 2*2 fiber coupler can be adjusted according to the intensity of the laser to be measured and actual needs. When there is no obvious difference in the intensity of the reference laser and the laser to be measured, a 50:50 splitting ratio is usually selected to equally divide the reference laser and the laser to be measured into two optical fibers to obtain a reference arm signal and an interference arm signal.

[0063] As a preferred embodiment, Figure 3 As shown, the optical path adjustment unit 104 includes a piezoelectric ceramic 301, a piezoelectric driving module 302 and a voltage control module 303; the interference arm optical fiber 105 is wound on the piezoelectric ceramic 301;

[0064] The voltage control module 303 is used to send a driving signal to the piezoelectric driving module 302;

[0065] The piezoelectric driving module 302 is used to drive and control the piezoelectric ceramic 301 according to the driving signal;

[0066] The piezoelectric ceramic 301 is used to produce a diameter change under the control of the piezoelectric driving module 302, so that the reference arm signal and the interference arm signal produce a preset optical path difference.

[0067] As a preferred embodiment, the reference arm optical fiber and the interference arm optical fiber are single-mode optical fibers or hollow-core optical fibers.

[0068] As a specific embodiment, the interference arm optical fiber 105 and the reference arm optical fiber 106 can be single-mode optical fibers; they can also be adjusted to hollow-core optical fibers according to needs to reduce the transmission loss of the laser being measured. Generally, when the wavelength of the laser being measured is shorter, an optical fiber with a smaller transmission loss is selected to provide more accurate raw data for subsequent wavelength detection.

[0069] Since the measured light is mostly laser used in industry, the wavelength range is usually between 600nm-1600nm. In order to better obtain the interference spectrum of the measured laser, as a specific embodiment, the preset optical path difference is 20cm.

[0070] As a specific embodiment, the number of turns of the interference arm optical fiber 105 wound on the piezoelectric ceramic 301 should match the size and expansion performance of the piezoelectric ceramic 301, so that the optical path difference of the piezoelectric ceramic 301 after being driven to expand can be controlled within the preset optical path difference, that is, about 20 cm.

[0071] As a preferred embodiment, the band-stop unit 109 includes a band-stop filter;

[0072] The band-stop filter is used to filter out the interference light signal of the reference light in the mixed light signal to obtain the laser interference light signal to be measured.

[0073] As a preferred embodiment, the bandpass unit 108 includes a bandpass filter;

[0074] The bandpass filter is used to separate the interference light signal of the reference light from the mixed light signal to obtain the reference laser interference light signal.

[0075] As a preferred embodiment, the data analysis module 203 includes an FPGA processor.

[0076] The above-mentioned all-fiber laser wavelength detection device is described below through an embodiment including specific devices.

[0077] As a specific example, Figure 4As shown, the all-fiber laser wavelength detection device includes a helium-neon laser light source, a laser input unit to be measured, a first fiber coupler, piezoelectric ceramics, a piezoelectric ceramic driver, a reference arm fiber, an interference arm fiber, a second fiber coupler, a bandpass filter, a bandstop filter, a first photodetector, a second photodetector, an analog-to-digital conversion module, an FPGA module, and an analysis module.

[0078] The first optical fiber coupler and the second optical fiber coupler are both 2*2 optical fiber couplers with a splitting ratio of 50:50.

[0079] The interference arm optical fiber is wound on the piezoelectric ceramic. Under static conditions, the interference arm optical fiber and the reference arm optical fiber are equal in length and match each other.

[0080] The piezoelectric ceramic produces a micro-deformation after the voltage is applied by the piezoelectric ceramic driver, thereby controllably changing the length and refractive index of the optical fiber wound on the piezoelectric ceramic. The voltage and time length applied by the ceramic driver are controlled by the FPGA module.

[0081] When the piezoelectric ceramic expands periodically under the control of the piezoelectric ceramic driver, an optical path difference of about 20 cm is generated between the interference arm signal and the reference arm signal, so that the reference light and the light to be measured produce an interference spectrum under the condition of the same optical path difference.

[0082] The interference spectrum is evenly divided into two paths through the second optical fiber coupler. The second optical fiber coupler has two outlets. Both outlets output a mixed spectrum of the reference laser interference spectrum and the laser interference spectrum to be measured.

[0083] The mixed spectrum passes through a band-stop filter to filter out the interference spectrum of the reference light and obtain the laser interference light signal to be measured; the mixed spectrum passes through a band-pass filter to separate the interference spectrum of the reference light from the mixed spectrum and obtain the reference laser interference light signal.

[0084] The laser interference light signal to be measured and the reference laser interference light signal are converted into electrical signals by the first photodetector and the photodetector respectively, and then converted into digital signals by the analog-to-digital conversion module and then stored and transmitted by the FPGA module.

[0085] The analysis module analyzes the interference signal data of the reference light and the light to be measured under the same optical path difference, analyzes the fringe orders of the two interference spectra, and demodulates the wavelength information of the laser to be measured according to the known wavelength value of the reference light.

[0086] Specifically, the method for demodulating the wavelength information of the laser to be measured according to the wavelength value of the reference light is:

[0087] Using the fringe order method, assuming that the wavelength of the reference beam is λ0, the measured interference fringe numbers of the reference light and the measured beam are m0 and m respectively, then the wavelength of the measured beam is λ=m0λ0 / m.

[0088] This embodiment also provides an all-fiber laser wavelength detection method, using any of the all-fiber laser wavelength detection devices described in the above technical solutions, such as Figure 5 As shown, the method includes:

[0089] Step S101: generating a reference laser through the reference light generator, and obtaining the laser to be measured through the light input unit to be measured;

[0090] Step S102: Splitting the reference laser and the laser to be measured into the reference arm optical fiber and the interference arm optical fiber respectively through the first coupler to obtain a reference arm signal and an interference arm signal; the optical path adjustment unit causes the reference arm signal and the interference arm signal to generate a preset optical path difference;

[0091] Step S103: receiving a mixed optical signal formed by the reference arm signal and the interference arm signal through a second coupler, and inputting the mixed optical signal into the band-stop unit and the band-pass unit; performing band-stop filtering and band-pass filtering on the mixed optical signal through the band-stop unit and the band-pass unit, respectively, to obtain a laser interference optical signal to be measured and a reference laser interference optical signal;

[0092] Step S104: The signal processing unit performs photoelectric conversion on the laser interference light signal to be measured and the reference laser interference light signal to obtain a laser detection signal to be measured and a reference laser interference detection signal, and determines the wavelength of the laser to be measured based on the reference laser detection signal and the laser detection signal to be measured.

[0093] The present invention discloses an all-fiber laser wavelength detection device and method. First, a reference laser is generated by a reference light generator, and the laser to be measured is obtained by a light input unit to be measured. Second, a reference arm optical fiber and an interference arm optical fiber are used to obtain a reference arm signal and an interference arm signal. Third, a mixed optical signal formed by the reference arm signal and the interference arm signal is subjected to bandpass filtering and bandstop filtering to obtain a laser interference light signal to be measured and a reference laser interference light signal. Finally, the laser interference light signal to be measured and the reference laser interference light signal are subjected to photoelectric conversion, and the wavelength of the laser to be measured is determined according to the reference laser detection signal and the laser detection signal to be measured.

[0094] In the device of the present invention, both the reference light and the light to be measured are transmitted in the optical fiber, and the generation environment of the interference light is transferred to the inside of the optical fiber, thereby avoiding the interference of the external environment on the optical path; the use of optical fiber to build the interference optical path greatly simplifies the complexity of the optical path adjustment, omitting the components such as the reflector and the spectroscope in the traditional optical wavelength meter, and also optimizes the cumbersome adjustment process that needs to consider the position and angle of each component when building the traditional optical path; the structure of the device is more modular, and the type of optical fiber can be adjusted and replaced according to the specific measurement requirements, which can meet the detection needs of different types of lasers.

[0095] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An all-fiber laser wavelength detection device, characterized in that: include: A reference light generator, a light input unit to be measured, a first coupler, an optical path adjustment unit, a reference arm optical fiber, an interference arm optical fiber, a second coupler, a band-stop unit, a band-pass unit and a signal processing unit; The reference light generator is used to generate reference laser light; The light input unit to be measured is used to obtain the laser to be measured; The first coupler is used to split the reference laser and the laser to be measured into the reference arm optical fiber and the interference arm optical fiber respectively, so as to obtain a reference arm signal and an interference arm signal; The reference arm optical fiber and the interference arm optical fiber match each other; The optical path adjustment unit is used to make the reference arm signal and the interference arm signal produce a preset optical path difference; The second coupler is used to receive a mixed optical signal formed by the reference arm signal and the interference arm signal, and input the mixed optical signal into the band-stop unit and the band-pass unit; The band-stop unit is used to perform band-stop filtering on the mixed optical signal to obtain a laser interference optical signal to be measured; The bandpass unit is used to perform bandpass filtering on the mixed optical signal to obtain a reference laser interference optical signal; The signal processing unit is used to perform photoelectric conversion on the laser interference light signal to be measured and the reference laser interference light signal to obtain a laser detection signal to be measured and a reference laser interference detection signal, and determine the wavelength of the laser to be measured based on the reference laser detection signal and the laser detection signal to be measured.

2. The all-fiber laser wavelength detection device according to claim 1, characterized in that: The signal processing unit includes a photoelectric conversion module, an analog-to-digital conversion module and a data analysis module; The photoelectric conversion module is used to convert the laser interference light signal to be measured and the reference laser interference light signal into a laser detection signal to be measured and a reference laser interference detection signal respectively; The analog-to-digital conversion module is used to convert the laser detection signal to be measured and the reference laser interference detection signal into digital signals; The data analysis module is used to collect and analyze the laser detection signal to be measured and the reference laser interference detection signal converted into digital signals, and determine the wavelength of the laser to be measured.

3. The all-fiber laser wavelength detection device according to claim 1, characterized in that: The reference light generator is a helium-neon laser generator.

4. The all-fiber laser wavelength detection device according to claim 1, characterized in that: The first coupler and the second coupler are both 2*2 optical fiber couplers.

5. The all-fiber laser wavelength detection device according to claim 1, characterized in that: The optical path adjustment unit includes a piezoelectric ceramic, a piezoelectric driving module and a voltage control module; the interference arm optical fiber is wound on the piezoelectric ceramic; The voltage control module is used to send a driving signal to the piezoelectric driving module; The piezoelectric driving module is used to drive and control the piezoelectric ceramic according to the driving signal; The piezoelectric ceramic is used to produce a diameter change under the control of the piezoelectric driving module, so that the reference arm signal and the interference arm signal produce a preset optical path difference.

6. The all-fiber laser wavelength detection device according to claim 1, characterized in that: The band-stop unit includes a band-stop filter; The band-stop filter is used to filter out the interference light signal of the reference light in the mixed light signal to obtain the laser interference light signal to be measured.

7. The all-fiber laser wavelength detection device according to claim 1, characterized in that: The bandpass unit includes a bandpass filter; The bandpass filter is used to separate the interference light signal of the reference light from the mixed light signal to obtain the reference laser interference light signal.

8. The all-fiber laser wavelength detection device according to claim 1, characterized in that: The reference arm optical fiber and the interference arm optical fiber are single-mode optical fibers or hollow-core optical fibers.

9. The all-fiber laser wavelength detection device according to claim 2, characterized in that: The data analysis module includes an FPGA processor.

10. An all-fiber laser wavelength detection method, using the all-fiber laser wavelength detection device according to any one of claims 1 to 9, characterized in that: include: Generate reference laser light through the reference light generator, and obtain the laser light to be measured through the light input unit to be measured; The reference laser and the laser to be measured are respectively split into the reference arm optical fiber and the interference arm optical fiber by the first coupler to obtain a reference arm signal and an interference arm signal; the optical path adjustment unit causes the reference arm signal and the interference arm signal to generate a preset optical path difference; The mixed optical signal formed by the reference arm signal and the interference arm signal is received by a second coupler, and the mixed optical signal is input into the band-stop unit and the band-pass unit; the mixed optical signal is subjected to band-stop filtering and band-pass filtering respectively by the band-stop unit and the band-pass unit to obtain a laser interference optical signal to be measured and a reference laser interference optical signal; The signal processing unit performs photoelectric conversion on the laser interference light signal to be measured and the reference laser interference light signal to obtain a laser detection signal to be measured and a reference laser interference detection signal, and determines the wavelength of the laser to be measured based on the reference laser detection signal and the laser detection signal to be measured.

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