Wavelength measurement method and system based on sinusoidal phase modulation interference technology

Abstract

The invention provides a wavelength measurement method and system based on a sinusoidal phase modulation interference technology, and relates to the technical field of wavelength measurement, and the method comprises the steps: obtaining a to-be-measured wavelength laser source and a reference laser source with a known wavelength, introducing the to-be-measured wavelength laser source and the reference laser source into an improved Michelson interferometer, and generating a first reference interference signal and a first measurement interference signal; performing phase modulation on the first reference interference signal and the first measurement interference signal to obtain a second reference interference signal and a second measurement interference signal which comprise high-frequency phase carriers, and extracting the phase of the reference interference signal and the phase of the measurement interference signal through an improved PGC-Arctan demodulation algorithm; performing fast Fourier transform on the phase of the reference interference signal and the phase of the measurement interference signal, and determining the amplitude of the reference interference signal and the amplitude of the measurement interference signal; and calculating the wavelength of the wavelength laser source to be measured according to the reference interference signal amplitude, the measurement interference signal amplitude and the known wavelength of the reference laser source.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wavelength measurement, in particular to a wavelength measurement method and system based on sinusoidal phase modulation interference technology. BACKGROUND

[0002] Wavelength measurement technology is one of the core foundations of modern optical research and application, and it plays an important role in many frontier fields such as precision manufacturing, communication technology, quantum science, etc. With the progress of science and technology, wavelength measurement technology has evolved from traditional methods to modern high-precision technology, which has promoted breakthroughs and progress in optics, materials science and other technical fields. Especially under the demand of ultra-precision measurement, how to break through the bottleneck of existing technology to achieve higher precision, wider spectral coverage and stronger environmental adaptability has become the key to the development of wavelength measurement technology.

[0003] Current wavelength measurement technologies mainly include optical frequency comb method, quantum sensing method, spectral analysis method, super-long wave astronomical modeling method, arbitrary waveform generator (AWG) method and various interference measurement methods, etc. Among them, the optical frequency comb method can provide ultra-high precision wavelength or frequency measurement, and has shown excellent ability in theory and experiment. The optical frequency comb method uses a mode-locked laser to generate equally spaced ultra-narrow pulses, and measures the wavelength by accurately measuring the frequency of the pulses, with a precision of 10-12 meters. Interference method is another commonly used and mature technology, which usually extracts wavelength information through the change of interference fringes. These technologies are widely used in precision measurement in laboratories and industries, but as the demand grows, the technical requirements and complexity of the equipment have also been higher.

[0004] However, although the existing wavelength measurement technology can theoretically achieve very high precision, it usually requires a high experimental environment and needs to be operated under low noise and constant temperature conditions, which limits the stability and precision in complex environments or practical applications. Traditional Michelson interferometers usually rely on mechanical rotation and manual observation of interference fringes, which is easy to introduce human error and affect the accuracy and consistency of the measurement. SUMMARY

[0005] In view of the above deficiencies of the prior art, the purpose of the embodiments of the present application is to provide a wavelength measurement method based on sinusoidal phase modulation interference technology, which can solve the technical problems that the existing wavelength measurement technology can theoretically achieve very high precision, but usually requires a high experimental environment and needs to be operated under low noise and constant temperature conditions, which limits the stability and precision in complex environments or practical applications. Traditional Michelson interferometers usually rely on mechanical rotation and manual observation of interference fringes, which is easy to introduce human error and affect the accuracy and consistency of the measurement.

[0006] The first aspect of the embodiment of the present application provides a wavelength measurement method based on a sinusoidal phase modulation interference technology, comprising:

[0007] S1: obtaining a wavelength laser source to be measured and a reference laser source with a known wavelength;

[0008] S2: introducing the reference laser source and the wavelength laser source to be measured into an improved Michelson interferometer to generate a first reference interference signal and a first measurement interference signal;

[0009] S3: respectively performing phase modulation on the first reference interference signal and the first measurement interference signal to obtain a second reference interference signal and a second measurement interference signal containing a high-frequency phase carrier;

[0010] S4: performing demodulation processing on the second reference interference signal and the second measurement interference signal by using an improved PGC-Arctan demodulation algorithm, and extracting a reference interference signal phase in the second reference interference signal and a measurement interference signal phase in the second measurement interference signal;

[0011] S5: performing fast Fourier transform on the reference interference signal phase and the measurement interference signal phase to determine a reference interference signal amplitude and a measurement interference signal amplitude;

[0012] S6: calculating the wavelength of the wavelength laser source to be measured according to the reference interference signal amplitude, the measurement interference signal amplitude, and the known wavelength of the reference laser source.

[0013] The second aspect of the embodiment of the present application provides a wavelength measurement system based on a sinusoidal phase modulation interference technology, comprising a processor and a memory.

[0014] The memory stores programs or instructions executable on the processor, and the programs or instructions are executed by the processor to implement the steps of the wavelength measurement method based on the sinusoidal phase modulation interference technology according to the first aspect.

[0015] The third aspect of the embodiment of the present application provides a readable storage medium, and the readable storage medium stores programs or instructions, and the programs or instructions are executed by the processor to implement the steps of the wavelength measurement method based on the sinusoidal phase modulation interference technology according to the first aspect.

[0016] The technical scheme provided by the embodiment of the present application has at least the following beneficial effects:

[0017] In the embodiments of the present application, by introducing phase modulation and improved PGC-Arctan demodulation algorithm, the high requirements for experimental environment are effectively reduced, the system has stronger robustness to environmental factors such as noise and temperature change, thereby ensuring high-precision measurement in complex environment. Fast Fourier transform further enhances the accuracy of signal analysis, ensuring stability and consistency. The use of digital phase modulation and automatic demodulation technology eliminates the influence of human error and mechanical error, greatly improving the measurement accuracy and stability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In the drawings:

[0019] Figure 1 is a flowchart of a wavelength measurement method based on sinusoidal phase modulation interference technology provided by the embodiments of the present application;

[0020] Figure 2 is a schematic diagram of an optical path structure of an improved Michelson interferometer provided by the embodiments of the present application;

[0021] Figure 3 is a flowchart of an improved PGC-Arctan demodulation algorithm introducing Lissajous ellipse correction provided by the embodiments of the present application;

[0022] Figure 4 is a schematic diagram of a wavelength measurement system based on sinusoidal phase modulation interference technology provided by the embodiments of the present application. DETAILED DESCRIPTION

[0023] In order to enable persons skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. It should be understood that these descriptions are only exemplary, and are not used to limit the scope of the present application. Based on the embodiments of the present application, all other embodiments obtained by persons skilled in the art without creative labor should fall within the scope of protection of the present application.

[0024] The wavelength measurement method based on sinusoidal phase modulation interference technology provided by the embodiments of the present application will be described in detail below with reference to the drawings and specific embodiments and application scenarios.

[0025] Reference is made to the accompanying drawingsFigure 1 Figure 1 shows a flowchart of a wavelength measurement method based on the sine phase modulation interference technology according to an embodiment of the present application.

[0026] Figure 2 shows a schematic diagram of an improved Michelson interferometer according to an embodiment of the present application. Figure 2 Figure 3 shows a schematic diagram of an improved PGC-Arctan demodulation algorithm with Lissajous ellipse correction according to an embodiment of the present application.

[0027] Figure 3 Figure 4 shows a flowchart of an improved PGC-Arctan demodulation algorithm with Lissajous ellipse correction according to an embodiment of the present application.

[0028] The wavelength measurement method based on the sine phase modulation interference technology according to an embodiment of the present application can include the following steps:

[0029] S1: Obtain a reference laser source with a known wavelength and a wavelength laser source to be measured.

[0030] S2: Introduce the reference laser source and the wavelength laser source to be measured into the improved Michelson interferometer to generate a first reference interference signal and a first measurement interference signal.

[0031] The improved Michelson interferometer is an optical instrument based on the principle of the Michelson interferometer, which is used to accurately measure the interference phenomenon, displacement, wavelength and other parameters of light waves. Compared with the traditional Michelson interferometer, the improved Michelson interferometer has been optimized and enhanced in structure and function to improve the measurement accuracy and sensitivity, and has been widely used in the fields of wavelength measurement, displacement measurement and the like.

[0032] In a possible implementation, the improved Michelson interferometer specifically includes a first polarizer H1, a first polarization beam splitter PBS1, a non-polarization beam splitter BS, a PZT displacement stage, a first corner cube mirror M1, a second corner cube mirror M2, a second polarization beam splitter PBS2, an EOM electro-optic modulator, a first optical filter F1, a second optical filter F2, a photodetector PD1, a photodetector PD2 and a second polarizer H2.

[0033] The first polarizer H1, the first polarization beam splitter PBS1, the non-polarization beam splitter BS, the second corner cube mirror M2, the PZT displacement stage, the first corner cube mirror M1, the EOM electro-optic modulator, the second polarization beam splitter PBS2, the first optical filter F1 and the photodetector PD1 are sequentially connected.

[0034] The second polarizer H2, the first polarization beam splitter PBS1, the non-polarization beam splitter BS, the second corner cube mirror M2, the PZT displacement stage, the first corner cube mirror M1, the EOM electro-optic modulator, the second polarization beam splitter PBS2, the second optical filter F2 and the photodetector PD1 are sequentially connected.​

[0035] In one possible implementation, S2 specifically includes:

[0036] S201: Adjusting the reference laser source through the first polarizer H1 to adjust the polarization state of the light beam to vertical polarization light.

[0037] S202: After transmitting the vertical polarization light through the first polarization beam splitter PBS1, the light is divided into probe light and modulation light at the non-polarization beam splitter BS.

[0038] S203: Reflecting the probe light into the second polarization beam splitter PBS2 through the second corner cube mirror on the PZT displacement table.

[0039] S204: After the modulation light is reflected by the first corner cube mirror M1, the phase modulation is performed on the modulation light by the EOM electro-optic modulator to generate a high-frequency phase carrier.

[0040] S205: The high-frequency phase carrier is combined with the probe light reflected into the second polarization beam splitter PBS2 through the second polarization beam splitter PBS2, and is input to the photodetector PD1 to obtain a first reference interference signal.

[0041] S206: Adjusting the to-be-measured wavelength laser source through the second polarizer H2 to adjust the polarization state of the light beam to horizontal polarization light, and obtaining a first measurement interference signal in the same way as the reference laser source.

[0042] Specifically, a HeNe laser (HRS015B, Thorlabs) with a wavelength of 632.8 nm is used as a known light source. The frequency and wavelength of the laser are accurately measured by an FP interferometer before leaving the factory, and can be used as a standard reference wavelength. The light beam emitted by the reference laser passes through the adjustment of the H1 polarizer, and the polarization state is vertically polarized and completely transmitted through PBS1. At BS, the light is divided into two paths, the transmitted light is called probe light, and the reflected light is called modulation light. The probe light enters PBS2 after being reflected by the M2 corner cube mirror fixed on the PZT displacement table, and the other path is reflected by the M1 pouring machine and then passes through the EOM electro-optic modulator. The EOM performs phase modulation on the light beam to generate a high-frequency phase carrier, which is then transmitted through PBS2 to combine with the probe light, undergoes optical mixing, and is finally received by the photodetector PD1 to generate S r (t) signal. The to-be-measured laser beam also passes through the above optical path, except that the polarization state of the to-be-measured laser beam needs to be adjusted to horizontal polarization before entering the Michelson interference optical path, that is, the polarization states of the to-be-measured light and the measurement light are orthogonal. The to-be-measured light beam passes through the same optical path to form an optical mixing signal which is received by the photodetector PD2 to generate S m (t) signal.

[0043] It should be noted that a double laser interference optical path is improved on the basis of the optical path of the traditional Michelson interferometer. The scheme uses a known wavelength light source as a reference light source, drives M2 high-frequency micro-vibration through piezoelectric ceramic and other equipment, interferes with the light source to be measured, captures the orthogonal polarization interference signal on the photoelectric detector, and then uses the self-developed software (PGC demodulation algorithm) on Labview to demodulate the data, and obtains the final wavelength. The error between the calculated value and the actual value is kept within ±0.1 nm.

[0044] In the embodiments of the present application, high precision of wavelength measurement is achieved by precisely controlling the polarization state of light, phase modulation, optical path difference and collection of interference signals. Through these technologies, the improved Michelson interferometer can eliminate the light source deviation, optimize the generation and demodulation process of the interference signal, and improve the measurement sensitivity of the small displacement and wavelength change. These optimized designs provide a more reliable experimental basis for actual wavelength measurement.

[0045] It should be noted that when two coherent light waves meet, they will interfere, forming interference fringes with light and dark. The distribution and intensity of these fringes are determined by the phase difference of the two light beams, and the phase difference is mainly affected by the wavelength and the difference in the length of the propagation path (i.e. the optical path difference) of the light. In the interference experiment, when the optical path difference of the two light beams is an integer multiple of the wavelength, constructive interference occurs, forming bright fringes; when the optical path difference is an odd multiple of half the wavelength, destructive interference occurs, forming dark fringes, so the distribution of interference fringes directly reflects the wavelength information of the light. In interference measurement, light waves of different wavelengths have different interference fringe distribution characteristics.

[0046] In Doppler interference, the phase of the interference signal is modulated by the measured moving object. Two laser beams of different wavelengths are used to detect the same displacement, and the wavelengths of the two laser beams are λ1 and λ2, and the measured displacement is d. Then the phase change of the displacement to the interference signal is:

[0047]

[0048] wherein, represents the phase change of the reference laser source, λ1 represents the wavelength of the reference laser source, d represents the measured displacement, represents the phase change of the wavelength laser to be measured, λ2 represents the wavelength of the wavelength laser to be measured.

[0049] From the formula, the phase change of the interference signal is inversely proportional to the wavelength, that is, different wavelengths of light detect the same displacement, and the phase change of the interference signal is different. For the wavelength measurement system designed in this project, the phases of the two signals are demodulated respectively, the phase change generated by the measured object is calculated, the ratio of the phase changes of the two signals is calculated, and the wavelength of the measured laser is calculated by combining the known wavelength of the reference light. Therefore, the high-precision phase demodulation of the two detection signals is the key to realizing the wavelength measurement of the present work.

[0050] S3: respectively phase modulating the first reference interference signal and the first measurement interference signal to obtain the second reference interference signal and the second measurement interference signal containing high-frequency phase carriers.

[0051] S4: respectively demodulating the second reference interference signal and the second measurement interference signal by improving the PGC-Arctan demodulation algorithm to extract the reference interference signal phase in the second reference interference signal and the measurement interference signal phase in the second measurement interference signal.

[0052] Among them, the improved PGC-Arctan demodulation algorithm is an algorithm for accurately demodulating interference signals, commonly used in interference measurement, displacement measurement, wavelength measurement and other fields. This algorithm can effectively extract and restore small displacement changes or other measured physical quantities by combining phase generation carrier (PGC) technology and arctangent (Arctan) method.

[0053] In one possible implementation, S4 specifically includes:

[0054] S401: using PGC demodulation technology, mixing the second reference interference signal, a frequency carrier signal and a two-frequency carrier signal.

[0055] S402: filtering the second reference interference signal after mixing by a low-pass filter to obtain a phase quadrature signal pair:

[0056]

[0057] Among them, Q(t) represents the quadrature component, G represents the amplitude of the fundamental frequency carrier signal, I 1r represents the amplitude of the alternating component of the reference interference signal, J1 represents the first-order Bessel function, C r represents the modulation depth of the carrier in the reference interference signal phase, α represents the phase delay between the phase carrier and the mixing carrier signal, represents the real-time phase of the reference signal, I(t) represents the same component, H represents the amplitude of the two-frequency carrier signal, J2 represents the second-order Bessel function, θ r represents the phase difference, sin represents the sine function, and cos represents the cosine function.

[0058] Among them, the low-pass filter (Low Pass Filter, LPF) is a common signal processing tool, which is used to allow signals below a certain frequency (i.e. cutoff frequency) to pass through, while suppressing signals above that frequency. It is a kind of frequency domain filtering, widely used in electronics, communications, audio processing, image processing and other fields.

[0059] In the embodiment of the present application, the improved PGC technology is used to mix the second reference interference signal with the one frequency carrier and the two frequency carrier signal, and then filter out the high frequency noise through the low-pass filter, only retaining the low frequency part related to the signal change. Effectively remove unnecessary high frequency components in the interference signal, only retain low frequency information. Through filtering, the signal is cleaner, the noise is suppressed, the signal-to-noise ratio of the signal is increased, and the accuracy of phase demodulation is improved.

[0060] S403: Draw a Lissajous figure based on the phase quadrature signal pair.

[0061] Among them, the Lissajous figure (Lissajous Curve) is a graph that depicts the relative relationship between two sinusoidal signals, which was discovered by French physicist Jules Antoine Lissajous in the 19th century and named after him. Lissajous figure is usually used to show the phase difference, frequency ratio and interaction between two periodic signals, widely used in signal processing, vibration analysis, interferometry and other fields.

[0062] S404: Perform ellipse fitting on the Lissajous figure by least squares method to obtain the basic parameters of the ellipse, wherein the basic parameters include the length of the horizontal axis, the length of the vertical axis, the coordinates of the center point and the inclination angle relative to the horizontal axis.

[0063] S405: Based on the basic parameters, use the correction formula to correct the phase quadrature signal pair.

[0064] In one possible implementation, the correction formula is specifically:

[0065]

[0066] Among them, Q N (t) represents the quadrature component after ellipse fitting, i0 represents the horizontal coordinate of the center point, q0 represents the vertical coordinate of the center point, r q represents the length of the vertical axis, I N (t) represents the co-directional component after ellipse fitting, r i represents the length of the horizontal axis.

[0067] In this embodiment of the invention, Lissajous ellipse correction technology is introduced. By correcting the phase signal pair using the least squares method, the influence caused by non-orthogonal errors can be reduced, making the signal pair more orthogonal and thus obtaining more accurate phase information. Simultaneously, this correction can effectively compensate for nonlinear errors caused by equipment errors, environmental factors, etc., improving the stability and reliability of the measurement.

[0068] S406: Perform a division operation on the phase-quadrature signal pairs after correction and use the Arctan algorithm for phase demodulation to obtain preliminary phase information.

[0069] In one possible implementation, the Arctan algorithm is used for phase demodulation, and the specific formula for obtaining preliminary phase information is as follows:

[0070]

[0071] in, Indicates preliminary phase information, Q N (t) represents the orthogonal components after ellipse fitting, I N (t) represents the same-direction component after ellipse fitting, and Arctan represents the arctangent function.

[0072] In this embodiment of the invention, by performing a division operation on the corrected phase-orthogonal signal pairs and using the Arctan algorithm for phase demodulation, phase information can be extracted from the interferometric signal efficiently and accurately. The advantages of the Arctan algorithm include simplified calculation, improved demodulation accuracy, enhanced system stability, and reduced noise interference. These advantages have led to the widespread application of this method in fields such as interferometry, wavelength measurement, and displacement measurement.

[0073] S407: Based on the preliminary phase information, the phase of the reference interference signal is obtained using the unwrapping algorithm.

[0074] The Phase Unwrapping Algorithm is a technique used to solve the phase jump problem. Phase values ​​in phase measurements typically change periodically, meaning the phase fluctuates between -π and π, exhibiting a phase jump phenomenon. When the phase value reaches π or -π, it jumps to the boundary of another period. The goal of the Phase Unwrapping Algorithm is to recover continuous phase information, avoid the effects of these jumps, and obtain the true phase.

[0075] S408: Obtain the phase of the measured interference signal in the same manner as processing the phase of the reference interference signal.

[0076] Specifically, according to PGC demodulation, the first-harmonic carrier signal Gcos(ω) ct) and the double frequency carrier signal Hcos(2ω c t) and the double frequency carrier signal Hcos(2ω N t) and the double frequency carrier signal Hcos(2ω N t) and the double frequency carrier signal Hcos(2ω

[0077] In summary, the improved PGC-Arctan demodulation algorithm significantly improves the accuracy and stability of the interference signal demodulation by combining Lissajous figure analysis, ellipse fitting, phase correction, and unwrapping algorithms. It can effectively eliminate system errors and non-orthogonal errors, accurately extract small displacements or wavelength changes, and solve the problem of phase discontinuity caused by phase jumps. This algorithm not only improves the measurement accuracy in low signal-to-noise ratio and complex environments, but also has strong applicability, widely used in high-precision displacement, wavelength measurement, and interferometer instruments, providing a reliable solution for precision optical measurement.

[0078] S5: Perform fast Fourier transform on the reference interference signal phase and the measurement interference signal phase to determine the reference interference signal amplitude and the measurement interference signal amplitude.

[0079] Fast Fourier Transform (FFT) is a high-efficiency algorithm for calculating Discrete Fourier Transform (DFT). It reduces the computational complexity, making the calculation of Fourier transform more efficient when dealing with large data sets. FFT has a wide range of applications in signal processing, image processing, audio processing, communication, vibration signal analysis, quantum physics, and other fields.

[0080] In one possible implementation, S5 specifically includes:

[0081] S501: performing fast Fourier transform on the reference interference signal phase and the measured interference signal phase to obtain a frequency spectrum distribution of the reference interference signal phase and a frequency spectrum distribution of the measured interference signal phase.

[0082] S502: extracting an amplitude at an angular frequency 110π from the frequency spectrum distribution of the reference interference signal phase and the frequency spectrum distribution of the measured interference signal phase respectively to obtain a reference interference signal amplitude and a measured interference signal amplitude.

[0083] In the embodiment of the present application, by performing fast Fourier transform on the reference interference signal and the measured interference signal, the key frequency component and amplitude can be efficiently extracted in the frequency domain. This method provides higher signal-to-noise ratio, accurate amplitude extraction, and clear identification of the frequency component, which provides an accurate and stable basis for subsequent wavelength or displacement calculation.

[0084] S6: calculating the wavelength of the to-be-measured wavelength laser source according to the reference interference signal amplitude, the measured interference signal amplitude, and the known wavelength of the reference laser source.

[0085] In a possible implementation, the formula of the wavelength of the to-be-measured wavelength laser source is specifically:

[0086]

[0087] wherein λ m represents the wavelength of the to-be-measured laser, λ r represents the reference laser wavelength, A r (ω) represents the amplitude of the reference laser signal, A m (ω) represents the amplitude of the to-be-measured laser signal, and ω represents the angular frequency.

[0088] In the embodiment of the present application, the reference wavelength is used as a known quantity, and the amplitude ratio is used to calculate the wavelength of the to-be-measured laser, which can improve the measurement accuracy. Especially in interference measurement, the amplitude and phase information have a close relationship, and by means of this method, the error in the measurement process can be reduced, and the high reliability of the result is ensured. At the same time, by using the known reference wavelength and the amplitude ratio of the measured signal, the need for high-precision spectrometer equipment or other complex measurement tools is avoided. This method is simple and effective, and the wavelength of the to-be-measured laser can be obtained through simple calculation, which reduces the requirements for experimental equipment and cost.

[0089] The technical scheme provided by the embodiment of the present application has at least the following beneficial effects:

[0090] In the embodiment of the present application, by introducing phase modulation and improved PGC-Arctan demodulation algorithm, the high requirements for experimental environment are effectively reduced, the system has stronger robustness to environmental factors such as noise and temperature change, thereby ensuring high-precision measurement in complex environment. Fast Fourier transform further enhances the accuracy of signal analysis, ensuring stability and consistency. The use of digital phase modulation and automatic demodulation technology eliminates the influence of human error and mechanical error, greatly improves the measurement accuracy and the stability of the system.

[0091] Reference is made to the accompanying drawings Figure 4 , which shows a structural schematic diagram of a wavelength measurement system based on sinusoidal phase modulation interference technology provided by the embodiment of the present application.

[0092] The embodiment of the present application provides a wavelength measurement system 20 based on sinusoidal phase modulation interference technology, which comprises a processor 201 and a memory 202.

[0093] The memory 202 stores programs or instructions executable on the processor 201, and the programs or instructions are executed by the processor 201 to realize the steps of the above-mentioned wavelength measurement method based on sinusoidal phase modulation interference technology, and can achieve the same technical effects. To avoid repetition, the present application will not be described again.

[0094] It should be understood that the processor 201 in the embodiment of the present application can be a central processing unit (CPU), and the processor can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0095] It should also be understood that the memory 202 in embodiments of the present application can be volatile or nonvolatile memory, or can include both volatile and nonvolatile memory. Nonvolatile memory can be read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically EPROM (EEPROM), or flash memory. Volatile memory can be random access memory (RAM), used as external cache. By way of example, and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0096] The above-described embodiments can be implemented in part or in whole through software, hardware (e.g., circuitry), firmware, or any combination thereof. When implemented in software, the above-described embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When loaded and executed by a computer, the computer instructions or computer programs cause the computer to perform the processes or functions described above according to the embodiments of the present application. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable apparatus. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, such as from a website, a computer, a server, or a data center to another website, computer, server, or data center through a wired (e.g., infrared, wireless, microwave, etc.) manner. The computer-readable storage medium can be any available medium or a collection of medium accessible by a computer or a data storage device such as a server, data center, etc. containing one or more medium. The medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid state disk.

[0097] It should be understood that the size of the sequence number of each process described above does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0098] Those skilled in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0099] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices, apparatuses and units can refer to the corresponding processes in the foregoing method embodiments, which will not be described here.

[0100] In several embodiments provided by the present application, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other manners. For example, the embodiments of the apparatus described above are merely schematic. For example, the division of the units is only a logical function division. There can be another division manner for the actual implementation, for example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between different units, can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0101] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, can be located in one place, or can be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0102] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically, or two or more units can be integrated into one unit.

[0103] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the present application that essentially contribute to the prior art or the parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0104] The embodiment of the present application provides a readable storage medium, which includes: a program or instructions stored on the readable storage medium, the program or instructions are executed by a processor to realize the steps of the wavelength measurement method based on the sinusoidal phase modulation interference technology, and the same technical effects can be achieved. To avoid repetition, the present application will not be described again.

[0105] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, but not to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application. Any changes or replacements that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered within the protection scope of the present application.

Claims

1. A wavelength measurement method based on sinusoidal phase modulation interferometry, characterized in that, include: S1: Obtain the laser source of the wavelength to be measured and the reference laser source of the known wavelength; S2: Introduce the reference laser source and the laser source of the wavelength to be measured into the improved Michelson interferometer to generate a first reference interference signal and a first measurement interference signal; S3: Phase modulate the first reference interference signal and the first measurement interference signal respectively to obtain a second reference interference signal and a second measurement interference signal containing a high-frequency phase carrier; S4: By improving the PGC-Arctan demodulation algorithm, the second reference interference signal and the second measurement interference signal are demodulated respectively, and the reference interference signal phase in the second reference interference signal and the measurement interference signal phase in the second measurement interference signal are extracted. S5: Perform a fast Fourier transform on the phase of the reference interference signal and the phase of the measured interference signal to determine the amplitude of the reference interference signal and the amplitude of the measured interference signal; S6: Calculate the wavelength of the laser source to be measured based on the amplitude of the reference interference signal, the amplitude of the measured interference signal, and the known wavelength of the reference laser source.

2. The wavelength measurement method based on sinusoidal phase modulation interferometry according to claim 1, characterized in that, The improved Michelson interferometer specifically includes: a first polarizer H1, a first polarizing beam splitter PBS1, a non-polarizing beam splitter BS, a PZT displacement stage, a first pyramidal mirror M1, a second pyramidal mirror M2, a second polarizing beam splitter PBS2, an EOM electro-optic modulator, a first filter F1, a second filter F2, a photodetector PD1, a photodetector PD2, and a second polarizer H2; The first polarizer H1, the first polarizing beam splitter PBS1, the non-polarizing beam splitter BS, the second pyramidal mirror M2, the PZT displacement stage, the first pyramidal mirror M1, the EOM electro-optic modulator, the second polarizing beam splitter PBS2, the first filter F1, and the photodetector PD1 are connected in sequence. The second polarizer H2, the first polarizing beam splitter PBS1, the non-polarizing beam splitter BS, the second pyramidal mirror M2, the PZT displacement stage, the first pyramidal mirror M1, the EOM electro-optic modulator, the second polarizing beam splitter PBS2, the second filter F2, and the photodetector PD1 are connected in sequence.

3. The wavelength measurement method based on sinusoidal phase modulation interferometry according to claim 2, characterized in that, S2 specifically includes: S201: The reference laser source is adjusted by passing it through the first polarizer H1 to adjust the polarization state of the beam to vertical polarization. S202: After the vertically polarized light is transmitted through the first polarization beam splitter PBS1, it is split into probe light and modulation light at the non-polarization beam splitter BS; S203: The probe light is reflected into the second polarizing beam splitter PBS2 by the second pyramidal reflector on the PZT displacement stage; S204: After the modulated light is reflected by the first pyramidal reflector M1, it is phase-modulated by the EOM electro-optic modulator to generate a high-frequency phase carrier. S205: The high-frequency phase carrier is combined with the probe light reflected into the second polarization beam splitter PBS2 through the second polarization beam splitter PBS2, and input to the photodetector PD1 to obtain the first reference interference signal; S206: The laser source of the wavelength to be measured is adjusted by the second polarizer H2 to adjust the polarization state of the beam to horizontal polarization, and the first measurement interference signal is obtained in the same way as the reference laser source.

4. The wavelength measurement method based on sinusoidal phase modulation interferometry according to claim 1, characterized in that, S4 specifically includes: S401: Using PGC demodulation technology, the second reference interference signal, the first harmonic carrier signal, and the second harmonic carrier signal are mixed. S402: The second reference interference signal after mixing is filtered by a low-pass filter to obtain a pair of phase-orthogonal signal pairs: Where Q(t) represents the quadrature component, G represents the amplitude of the fundamental frequency carrier signal, and I 1r J1 represents the amplitude of the AC component of the reference interference signal, and C represents the first-order Bessel function. r The modulation depth of the carrier in the phase of the reference interference signal is represented by α, and the phase delay between the phase carrier and the mixing carrier signal is represented by α. Let I(t) represent the real-time phase of the reference signal, I(t) represent the in-phase component, H represent the amplitude of the second-harmonic carrier signal, J2 represent the second-order Bessel function, and θ represent the phase of the reference signal. r denoted by , sin represents the sine function, and cos represents the cosine function; S403: Based on the aforementioned phase-orthogonal signal pairs, draw a Lissajous figure; S404: The Lissajous figure is fitted with an ellipse using the least squares method to obtain the basic parameters of the ellipse, wherein the basic parameters include the length of the horizontal axis, the length of the vertical axis, the coordinates of the center point, and the tilt angle relative to the horizontal axis. S405: Based on the aforementioned basic parameters, the phase quadrature signal pair is corrected using a correction formula; S406: Perform a division operation on the phase quadrature signal pairs after correction and use the Arctan algorithm for phase demodulation to obtain preliminary phase information; S407: Based on the preliminary phase information, the phase of the reference interference signal is obtained using an unwrapping algorithm; S408: Obtain the phase of the measured interference signal in the same manner as processing the phase of the reference interference signal.

5. The wavelength measurement method based on sinusoidal phase modulation interferometry according to claim 4, characterized in that, The correction formula is as follows: Among them, Q N (t) represents the orthogonal components after ellipse fitting, i0 represents the x-coordinate of the center point, q0 represents the y-coordinate of the center point, and r q I represents the length of the vertical axis. N (t) represents the same-direction component after ellipse fitting, r i Indicates the length of the horizontal axis.

6. The wavelength measurement method based on sinusoidal phase modulation interferometry according to claim 4, characterized in that, The specific formula for obtaining preliminary phase information using the Arctan algorithm in S406 is as follows: in, Indicates preliminary phase information, Q N (t) represents the orthogonal components after ellipse fitting, I N (t) represents the same-direction component after ellipse fitting, and Arctan represents the arctangent function.

7. The wavelength measurement method based on sinusoidal phase modulation interferometry according to claim 1, characterized in that, S5 specifically includes: S501: Perform a fast Fourier transform on the phase of the reference interference signal and the phase of the measured interference signal to obtain the spectral distribution of the phase of the reference interference signal and the spectral distribution of the phase of the measured interference signal; S502: Extract the amplitude at angular frequency 110π from the spectral distribution of the phase of the reference interference signal and the spectral distribution of the phase of the measured interference signal, respectively, to obtain the amplitude of the reference interference signal and the amplitude of the measured interference signal.

8. The wavelength measurement method based on sinusoidal phase modulation interferometry according to claim 1, characterized in that, The formula for the wavelength of the laser source to be measured is as follows: Where, λ m λ represents the wavelength of the laser being measured. r Indicates the reference laser wavelength, A r (ω) represents the amplitude of the reference laser signal, A m (ω) represents the amplitude of the laser signal to be measured, and ω represents the angular frequency.

9. A wavelength measurement system based on sinusoidal phase modulation interferometry, characterized in that, include: Processor and memory; The memory stores programs or instructions that can run on the processor, which, when executed by the processor, implement the steps of the wavelength measurement method based on sinusoidal phase modulation interferometry as described in any one of claims 1 to 8.

10. A readable storage medium, characterized in that, The readable storage medium stores a program or instructions that, when executed by a processor, implement the steps of the wavelength measurement method based on sinusoidal phase modulation interferometry as described in any one of claims 1 to 8.

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