A spectrum splicing device and method for wavelength segmented continuous scanning laser

Abstract

The present invention discloses a spectrum splicing device for wavelength segmented continuous scanning laser, comprising a semiconductor tunable laser, a laser driving circuit, a first fiber coupler, a second fiber coupler, a fiber interference measurement module, a reference fiber interferometer, a fiber thermally stable etalon, a balanced photodetector, a first photodetector, a second photodetector and a data acquisition and processing module. The present invention also discloses a splicing method, which performs nonlinear frequency sweep correction on the fiber interference measurement module signal and the thermally stable etalon signal by referring to the fiber interferometer signal to obtain a resampled signal, and calculates the start and end points of the frequency of each segment of the optical signal according to the peak position of the resampled thermally stable etalon to realize spectrum splicing. The present invention performs high-precision splicing of segmented continuous optical bands through optical fiber devices and algorithms, which has far-reaching significance for the application of wavelength segmented continuous scanning lasers in optical frequency domain reflection distributed optical fiber sensing systems.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical communication, and relates to a spectrum splicing device and method, and in particular to a spectrum splicing device and method for wavelength segmented continuous scanning laser. Background Art

[0002] In the optical frequency domain reflection distributed fiber sensing system, it is usually necessary to use a narrow line width and wide non-mode hopping range tunable laser as the light source (Mingming Luo, 0.5mm spatial resolution distributed fiber temperature and strain sensor with position-deviation compensation based on OFDR, Optics Express, 2019, 27 (24), 35823-35829), which has the problems of high cost, large volume, slow scanning speed, narrow operating temperature range, and high vibration reduction requirements. Existing semiconductor lasers such as tunable DBR lasers and DFB laser arrays have the advantages of small size, full solid state, fast scanning speed, and wide operating temperature range, and have been widely used in the field of optical communications. However, due to the problem of mode hopping during the scanning process of this type of laser, it is impossible to achieve continuous scanning without mode hopping in the full spectrum range (Zheng Shengheng, High-precision wavelength tuning characteristics of modulated grating Y-branch tunable laser, Acta Optica Sinica, 2019, 46 (2), 0201001), and can only achieve segmented continuous scanning, which limits its application in the optical frequency domain reflection distributed fiber sensing system. Summary of the invention

[0003] The purpose of the present invention is to overcome the above defects and provide a spectrum splicing device for wavelength segmented continuous scanning laser, comprising a semiconductor tunable laser, a laser driving circuit, a first fiber coupler, a second fiber coupler, a fiber interference measurement module, a reference fiber interferometer, a fiber thermal stability standard, a balanced photodetector, a first photodetector, a second photodetector and a data acquisition and processing module. The present invention also discloses a spectrum splicing method, wherein the laser emitted by the semiconductor tunable laser is passed through the fiber interferometer measurement module to obtain a beat frequency interference signal of the fiber measurement module, a periodic signal of equal optical wave frequency is obtained after passing through the reference fiber interferometer, a wavelength reference signal is obtained after passing through the fiber thermal stability standard, the peak position of the rth waveband and the corresponding optical frequency are obtained according to the resampled wavelength reference signal, the optical frequency step length of the rth waveband is obtained according to the periodic signal of equal optical wave frequency, the optical frequency starting point and focus of the rth waveband are obtained according to the peak position of the rth waveband and the corresponding optical frequency and the optical frequency step length, and then the signal segments in the beat frequency interference signal of the resampled fiber measurement module can be spliced. The present invention uses optical fiber devices and algorithms to perform high-precision splicing of segmented continuous optical bands, which has far-reaching significance for its application in optical frequency domain reflection distributed optical fiber sensing systems.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] A spectrum splicing device for wavelength segmented continuous scanning laser, comprising a semiconductor tunable laser, a laser driving circuit, a first fiber coupler, a second fiber coupler, a fiber interferometric measurement module, a reference fiber interferometer, a fiber thermally stable etalon, a balanced photodetector, a first photodetector, a second photodetector and a data acquisition and processing module;

[0006] The laser driving circuit controls the semiconductor tunable laser to output wavelength segmented and continuously scanned lasers;

[0007] The laser output by the semiconductor tunable laser is divided into two paths through the first optical fiber coupler, which are respectively recorded as the first laser path and the second laser path; the first laser path enters the optical fiber interferometry module, and the second laser path is divided into two paths after passing through the second optical fiber coupler, which are respectively recorded as the third laser path and the fourth laser path; the third laser path enters the reference optical fiber interferometer, and the fourth laser path enters the optical fiber thermal stability standard tool;

[0008] The optical fiber interferometry module receives the first laser beam and generates a beat frequency interference signal of the optical fiber measurement module and outputs it to the balanced photoelectric detector; the balanced photoelectric detector performs photoelectric conversion on the beat frequency interference signal of the optical fiber measurement module and outputs it to the data acquisition and processing module;

[0009] The reference optical fiber interferometer receives the third laser and generates a periodic signal of equal light wave frequency and outputs it to the first photodetector; the first photodetector performs photoelectric conversion on the periodic signal of equal light wave frequency and outputs it to the data acquisition and processing module;

[0010] The optical fiber thermally stable etalon receives the fourth laser and generates a wavelength reference signal; the second photoelectric detector performs photoelectric conversion on the wavelength reference signal and outputs it to the data acquisition and processing module;

[0011] The data acquisition and processing module receives the beat frequency interference signal, the periodic signal of the equal light wave frequency and the wavelength reference signal of the optical fiber measurement module after the photoelectric conversion and performs calculations to realize the splicing of the spectrum.

[0012] Further, the fiber interferometry module includes a third fiber coupler, a fourth fiber coupler, a fiber circulator and a sensing fiber;

[0013] The first path of laser light outputted by the first optical fiber coupler is divided into two paths after passing through the third optical fiber coupler, which are respectively recorded as the fifth path of laser light and the sixth path of laser light;

[0014] The fifth laser enters the sensing optical fiber through the input port of the optical fiber circulator and the bidirectional transmission port of the optical fiber circulator, and then Rayleigh scattering occurs. The Rayleigh scattered light enters the fourth optical fiber coupler through the bidirectional transmission port of the optical fiber circulator and the backward transmission port of the optical fiber circulator.

[0015] The sixth laser directly enters the fourth optical fiber coupler; the Rayleigh scattered light formed by the fifth laser and the sixth laser interfere in the fourth optical fiber coupler to generate a beat frequency interference signal of the optical fiber measurement module.

[0016] Further, the reference fiber interferometer includes a fifth fiber coupler, a first Faraday rotation mirror, a second Faraday rotation mirror and a delay fiber;

[0017] The third laser output by the second fiber coupler is input to the first port of the fifth fiber coupler, the third port of the fifth fiber coupler is connected to the first Faraday rotation mirror, the fourth port of the fifth fiber coupler is connected to the second Faraday rotation mirror via a delay fiber, and the second port of the fifth fiber coupler serves as the output port of the reference fiber interferometer.

[0018] Furthermore, the continuous scanning spectrum range of the semiconductor tunable laser is ≥100 GHz, and there is an optical frequency overlap of ≥5 GHz in adjacent optical bands, and the laser line width is ≤1 MHz;

[0019] The semiconductor tunable laser is a DBR tunable laser or a DFB laser;

[0020] The reference fiber optic interferometer is a fiber optic Michelson interferometer, and the difference in interferometer arm length is ≥1m.

[0021] Furthermore, the free spectral range of the optical fiber thermal stability etalon is ≤100 GHz and the finesse is ≥7.

[0022] A spectrum splicing method for wavelength segmented continuous scanning laser, implemented by using the above spectrum splicing device, comprises:

[0023] The laser band output by the semiconductor tunable laser is denoted as R band, and the periodic signal of equal optical wave frequency after photoelectric conversion received by the data acquisition and processing module includes R band periodic signals, wherein the sampling length of the rth periodic signal corresponding to the rth band is N r , the number of cycles is M r , r=1...R, the length of the reference fiber interferometer is l; the beat frequency interference signal of the optical fiber measurement module after photoelectric conversion and the wavelength reference signal received by the data acquisition and processing module are both segmented signals, respectively including R segment signals corresponding to the R segment band;

[0024] S1 according to N r 、M r The optical frequency width Δν of the rth band is calculated by r , and according to the optical frequency width Δν of the rth band r Get the optical frequency step length δν of the rth band r , r=1……R;

[0025] S2 resamples the beat frequency interference signal and the wavelength reference signal of the optical fiber measurement module after photoelectric conversion according to the periodic signal of equal light wave frequency after photoelectric conversion to obtain the beat frequency interference resampled signal and the wavelength reference resampled signal of the optical fiber measurement module;

[0026] S3 obtains the peak position i in the rth band signal corresponding to the rth band in the wavelength reference resampled signal r,p and the optical frequency ν corresponding to the peak position r,p , r=1……R;

[0027] S4 According to N r 、i r,p , ν r,p and δν r Calculate the starting point of the optical frequency ν of the rth band r,0 and optical frequency end point ν r,N ;

[0028] S5 takes the optical frequency end point ν of the r-1th band r-1,N and the optical frequency starting point ν of the rth band r,0 The midpoint ν′ r,0As a splicing point, the r-1th signal and the rth signal corresponding to the r-1th band and the rth band in the beat frequency interference resampling signal of the optical fiber measurement module are spliced, r = 2 ... R;

[0029] S6 repeats steps S1 to S5 to obtain the beat frequency interference resampling signal of the full-band optical fiber measurement module after the splicing is completed.

[0030] Furthermore, in step S1, the optical frequency width of the rth band

[0031] The optical frequency step length of the rth band

[0032] Where c is the speed of light in a vacuum and n is the effective refractive index of the optical fiber.

[0033] Further, in step S3, the peak position i in the signal corresponding to the rth band in the wavelength reference resampled signal is obtained. r,p Then, consult the fiber thermal stability etalon product manual to obtain the optical frequency ν corresponding to the peak position. r,p .

[0034] Furthermore, in step S4, the optical frequency starting point ν of the rth band r,0 =v r,p -i r,p δν r ;

[0035] The optical frequency end point ν of the rth band r,N =v r,p +(N r -i r,p )δν r .

[0036] Furthermore, the specific method of step S2 for resampling the beat frequency interference signal and wavelength reference signal of the optical fiber measurement module after photoelectric conversion according to the periodic signal of equal optical wave frequency after photoelectric conversion is to extract the positions of the peak points, half-peak points and trough points of the periodic signal of equal optical wave frequency, resample the beat frequency interference signal and wavelength reference signal of the optical fiber measurement module at the positions of the peak points, half-peak points and trough points to obtain resampled data, and then rearrange the resampled data at equal intervals to obtain the beat frequency interference resampled signal and wavelength reference resampled signal of the optical fiber measurement module.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The present invention creatively proposes a spectrum splicing device and method for wavelength segmented and continuously scanned lasers, which uses optical fiber devices and algorithms to perform high-precision splicing of wavelength segmented and continuously scanned light bands to achieve continuous measurement over the full spectrum range, which is beneficial to reducing system cost and volume and improving system reliability;

[0039] (2) The present invention discloses a spectrum splicing device and method for a wavelength segmented continuous scanning laser, which accurately calculates the starting frequency and the ending frequency of each band by referring to an interferometer and a thermally stable standard tool. Therefore, the overlapping optical frequency range of two adjacent bands is required to be small (≥5GHz), thereby avoiding the waste of resources and time caused by a large number of overlapping scans of the same band of the laser.

[0040] (3) The present invention discloses a spectrum splicing device and method for wavelength segmented continuous scanning laser, which can realize the application of semiconductor lasers such as tunable DBR lasers and DFB laser arrays in optical frequency domain reflection distributed optical fiber sensing systems, which is beneficial to reducing the cost and volume of the system and improving the system reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of a spectrum splicing device for wavelength segmented continuous scanning laser of the present invention;

[0042] Figure 2 It is a schematic diagram of resampling the beat frequency interference signal and wavelength reference signal of the segmented continuous optical fiber measurement module in segmented equal light wave frequency intervals according to the segmented continuous periodic signal of equal light wave frequency in the present invention;

[0043] Figure 3 It is a schematic diagram of splicing beat frequency interference signals of the optical fiber measurement module after resampling of the present invention;

[0044] In the figure:

[0045] 1-semiconductor tunable laser, 2-laser driving circuit, 31-first fiber coupler, 32-second fiber coupler, 4-fiber interferometry module, 5-reference fiber interferometer, 6-fiber thermal stability standard, 7-balanced photodetector, 81-first photodetector, 82-second photodetector, 9-data acquisition and processing module;

[0046] 33-third optical fiber coupler, 34-fourth optical fiber coupler, 10-optical fiber circulator, 11-sensing optical fiber;

[0047] 35 - fifth optical fiber coupler, 121 - first Faraday rotation mirror, 122 - second Faraday rotation mirror, 13 - delay optical fiber. DETAILED DESCRIPTION

[0048] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0049] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0050] Aiming at the problem that the existing semiconductor lasers such as tunable DBR lasers and DFB laser arrays can only realize segmented continuous scanning due to the mode hopping problem, the present invention proposes a spectrum splicing device and method for wavelength segmented continuous scanning laser, which can splice the segmented continuous optical bands with high precision through optical fiber devices and algorithms to meet its application in optical frequency domain reflection distributed optical fiber sensing systems. Figures 1 to 3 The technical solution of the present invention is described in detail.

[0051] like Figure 1 The present invention discloses a spectrum splicing device for wavelength segmented continuous scanning laser, comprising a semiconductor tunable laser 1, a laser driving circuit 2, a first fiber coupler 31, a second fiber coupler 32, a fiber interference measurement module 4, a reference fiber interferometer 5, a fiber thermal stability standard 6, a balanced photoelectric detector 7, a first photoelectric detector 81, a second photoelectric detector 82 and a data acquisition and processing module 9. The fiber interference measurement module 4 comprises a third fiber coupler 33, a fourth fiber coupler 34, a fiber circulator 10, and a sensing fiber 11; the reference fiber interferometer 5 comprises a fifth fiber coupler 35, a first Faraday rotating reflector 121, a second Faraday rotating reflector 122, and a delay fiber 13.

[0052] The laser driving circuit 2 controls the semiconductor tunable laser 1 to output wavelength segmented and continuously scanned laser light, which is divided into two paths after passing through the first optical fiber coupler 31;

[0053] The first laser output from the first fiber coupler 31 is input into the fiber interference measurement module 4. Specifically, the first light output from the first fiber coupler 31 is input into the first port of the third fiber coupler 33. The light output from the second port of the third fiber coupler 33 is input into the sensing fiber 11 after passing through the input port and the bidirectional transmission port of the fiber circulator 10. The light output from the sensing fiber 11 is input into the first port of the fourth fiber coupler 34 after passing through the bidirectional transmission port and the backward transmission port of the fiber circulator 10. The third port of the third fiber coupler 33 is input into the second port of the fourth fiber coupler 34. The two lights input from the first port and the second port of the fourth fiber coupler 34 interfere with each other. The third port and the fourth port of the fourth fiber coupler 34 serve as the output ports of the fiber interference measurement module, and output a segmented continuous beat frequency interference signal of the fiber measurement module. The signal is converted into a first electrical signal through the balanced photoelectric detector 7 to form a first electrical signal input into the data acquisition and processing module 9. The segmented continuous signal in the present invention refers to a signal containing multiple segments, and each segment of the signal itself is a continuous signal.

[0054] The second path of light outputted by the first optical fiber coupler 31 is divided into two paths after passing through the second optical fiber coupler 32;

[0055] The first path of light output by the second fiber coupler 32 is input to the reference fiber interferometer 5. Specifically, the first path of light output by the second fiber coupler 32 is input to the first port of the fifth fiber coupler 35. The third port of the fifth fiber coupler 35 is connected to the first Faraday rotation mirror 121. The fourth port of the fifth fiber coupler 35 is connected to the second Faraday rotation mirror 122 via the delay fiber 13. The second port of the fifth fiber coupler 35 serves as the output port of the reference fiber interferometer 5, outputs a segmented continuous periodic signal of equal light wave frequency, and undergoes photoelectric conversion via the first photodetector 81 to form a second path of electrical signal that is input to the data acquisition processing module 9.

[0056] The second light outputted by the second fiber coupler 32 is inputted into the input port of the optical fiber thermally stable etalon 6, and the output port of the thermally stable etalon 6 outputs a segmented continuous wavelength reference signal, which is photoelectrically converted by the second photodetector 82 to form a third electrical signal which is inputted into the data acquisition and processing module 9;

[0057] The data acquisition and processing module 9 acquires three-way signals and performs data analysis.

[0058] In the above-mentioned spectrum splicing device for wavelength segmented continuous scanning laser, the continuous scanning spectrum range of the semiconductor tunable laser 1 is ≥100GHz, and there is an optical frequency overlap of ≥1GHz in adjacent optical bands, and the laser line width is ≤1MHz. It is a DBR tunable laser or a DFB laser.

[0059] In the above-mentioned spectrum splicing device for wavelength segmented continuous scanning laser, the reference fiber interferometer 5 is a fiber Michelson interferometer, and the difference in interferometer arm length is ≥1m.

[0060] In the above-mentioned spectrum splicing device for wavelength segmented continuous scanning laser, the optical fiber thermal stability standard 6 has a free spectrum range of ≤100GHz and a finesse of ≥7.

[0061] The present invention provides a spectrum splicing method for wavelength segmented continuous scanning laser, comprising the following steps:

[0062] The semiconductor tunable laser 1 outputs R-segment wavelength segmented and continuously scanned laser. Through the spectrum splicing device, the periodic signal of equal light wave frequency output by the reference interferometer 5 includes R-segment periodic signals. The sampling length of each periodic signal is N1, N2, ..., N R , the number of cycles are M1, M2, ..., M R , where the sampling length of the periodic signal corresponding to the rth band is N r , the number of cycles is M r , the length l of the delay optical fiber 13.

[0063] 1) Calculate the optical frequency width of the rth band and optical frequency step Where c is the speed of light in a vacuum, and n is the effective refractive index of the optical fiber;

[0064] 2) If Figure 2 According to the segmented continuous equal light wave frequency periodic signal output by the reference interferometer 5, the segmented continuous fiber optic measurement module beat frequency interference signal output by the fiber optic interference measurement module 4 and the segmented continuous wavelength reference signal output by the fiber optic thermal stability standard 6 are segmented equal light wave frequency interval resampled; the specific method of resampling is: extracting the positions of the crest points, half-peak points and trough points of the periodic signal of equal light wave frequency, resampling the beat frequency interference signal and the wavelength reference signal of the fiber optic measurement module at these positions, and then rearranging them at equal intervals to obtain the beat frequency interference resampled signal and the wavelength reference resampled signal of the fiber optic measurement module.

[0065] 3) Peak search is performed on each band of the segmented wavelength reference resampled signal to obtain the peak position i of each segment of the wavelength reference resampled signal. 1,p ,i 2,p ,…,i R,p , and consult the product manual of the optical fiber thermal stability etalon. It is found that the optical frequencies of the peaks of the optical fiber thermal stability etalon are ν 1,p ,ν 2,p ,…,ν R,p , where the peak position of the rth band is i r,p, the corresponding optical frequency of the optical fiber thermal stability etalon peak is ν r,p ;

[0066] 4) Resample the signal according to the wavelength reference to find the peak position i in the rth segment of the signal r,p , the peak optical frequency ν r,p , optical frequency step length δν r , calculate the starting point ν of the optical frequency of the rth band r,0 =v r,p -i r,p δν r and the end point ν r,N =v r,p +(N r -i r,p )δν r ;

[0067] 5) Take the optical frequency end point ν of the r-1th band r-1,N and the starting point of the rth band optical frequency ν r,0 The midpoint ν′ r,0 As the splicing point, the r-1th segment signal and the rth segment signal in the beat frequency interference signal of the optical fiber measurement module after the segmented equal light wave frequency interval resampling are spliced, such as Figure 3 ;

[0068] 6) Repeat the above steps to obtain the optical frequency starting point and end point of all bands, and sequentially splice the adjacent segmented signals in the beat frequency interference signal of the optical fiber measurement module after equal optical wave frequency interval resampling to obtain the full-band Rayleigh scattering resampled signal.

[0069] The present invention performs nonlinear frequency sweep correction on the fiber interferometer measurement module signal and the thermally stable etalon signal with reference to the fiber interferometer signal to obtain a resampled signal, calculates the starting point and end point of each segment of the optical signal frequency according to the peak position of the resampled thermally stable etalon to achieve spectrum splicing, and can realize the application of wavelength segmented continuous scanning laser in the optical frequency domain reflection distributed optical fiber sensing system, which is beneficial to reducing system cost and volume and improving system reliability.

[0070] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0071] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A spectrum splicing device for wavelength segmented continuous scanning laser, characterized in that: The device comprises a semiconductor tunable laser (1), a laser driving circuit (2), a first optical fiber coupler (31), a second optical fiber coupler (32), an optical fiber interferometer measurement module (4), a reference optical fiber interferometer (5), an optical fiber thermal stability standard tool (6), a balanced photodetector (7), a first photodetector (81), a second photodetector (82) and a data acquisition and processing module (9); The laser driving circuit (2) controls the semiconductor tunable laser (1) to output wavelength segmented and continuously scanned laser light; The laser light outputted by the semiconductor tunable laser (1) is divided into two paths through a first optical fiber coupler (31), respectively recorded as a first laser light path and a second laser light path; the first laser light path enters an optical fiber interferometric measurement module (4), and the second laser light path is divided into two paths after passing through a second optical fiber coupler (32), respectively recorded as a third laser light path and a fourth laser light path; the third laser light path enters a reference optical fiber interferometer (5), and the fourth laser light path enters an optical fiber thermal stability standard tool (6); The optical fiber interference measurement module (4) receives the first laser beam and generates a beat frequency interference signal of the optical fiber measurement module and outputs it to a balanced photoelectric detector (7); the balanced photoelectric detector (7) performs photoelectric conversion on the beat frequency interference signal of the optical fiber measurement module and outputs it to a data acquisition and processing module (9); The reference optical fiber interferometer (5) receives the third laser beam and generates a periodic signal of equal optical wave frequency and outputs it to the first photodetector (81); the first photodetector (81) performs photoelectric conversion on the periodic signal of equal optical wave frequency and outputs it to the data acquisition and processing module (9); The optical fiber thermal stability etalon (6) receives the fourth laser and generates a wavelength reference signal; the second photoelectric detector (82) performs photoelectric conversion on the wavelength reference signal and outputs the converted signal to the data acquisition and processing module (9); The data acquisition and processing module (9) receives the beat frequency interference signal of the optical fiber measurement module after photoelectric conversion, the periodic signal of the same light wave frequency and the wavelength reference signal and performs calculation to realize the splicing of the spectrum; The laser waveband output by the semiconductor tunable laser (1) is denoted as R waveband, and the periodic signal of equal optical wave frequency after photoelectric conversion received by the data acquisition and processing module (9) includes R waveband periodic signals, wherein the sampling length of the rth waveband periodic signal is N r , the number of cycles is M r , r=1...R, the length of the reference optical fiber interferometer (5) is l; the beat frequency interference signal of the optical fiber measurement module and the wavelength reference signal received by the data acquisition and processing module (9) after the photoelectric conversion are both segmented signals, respectively including R segment signals corresponding to the R segment waveband; The spectrum splicing device of the wavelength segmented continuous scanning laser is used to implement a spectrum splicing method of the wavelength segmented continuous scanning laser, which specifically includes: S1 according to N r 、M r The optical frequency width Δν of the rth band is calculated by r , and according to the optical frequency width Δν of the rth band r Get the optical frequency step length δν of the rth band r , r=1……R; S2 resamples the beat frequency interference signal and the wavelength reference signal of the optical fiber measurement module after photoelectric conversion according to the periodic signal of equal light wave frequency after photoelectric conversion to obtain the beat frequency interference resampled signal and the wavelength reference resampled signal of the optical fiber measurement module; S3 obtains the peak position i of the rth segment signal in the wavelength reference resampled signal r,p and the optical frequency ν corresponding to the peak position r,p , r=1……R; S4 According to N r 、i r,p , ν r,p and δν r Calculate the starting point of the optical frequency ν of the rth band r,0 and optical frequency end point ν r,N ; S5 takes the optical frequency end point ν of the r-1th band r-1,N and the optical frequency starting point ν of the rth band r,0 The midpoint ν r ' ,0 As a splicing point, the r-1th signal and the rth signal in the beat frequency interference resampling signal of the optical fiber measurement module are spliced, where r=2...R; S6 repeats S1 to S5 to obtain the beat frequency interference resampling signal of the full-band optical fiber measurement module after the splicing is completed.

2. The spectrum splicing device of wavelength segmented continuous scanning laser according to claim 1, characterized in that: The optical fiber interference measurement module (4) comprises a third optical fiber coupler (33), a fourth optical fiber coupler (34), an optical fiber circulator (10) and a sensing optical fiber (11); The first path of laser light outputted by the first optical fiber coupler (31) is divided into two paths after passing through the third optical fiber coupler (33), which are respectively recorded as the fifth path of laser light and the sixth path of laser light; The fifth laser beam enters the sensing optical fiber (11) through the input port of the optical fiber circulator (10) and the bidirectional transmission port of the optical fiber circulator (10), and Rayleigh scattering occurs thereafter. The Rayleigh scattered light enters the fourth optical fiber coupler (34) through the bidirectional transmission port of the optical fiber circulator (10) and the backward transmission port of the optical fiber circulator (10); The sixth laser beam directly enters the fourth optical fiber coupler (34); the Rayleigh scattered light formed by the fifth laser beam and the sixth laser beam interfere in the fourth optical fiber coupler (34) to generate a beat frequency interference signal of the optical fiber measurement module.

3. The spectrum splicing device of wavelength segmented continuous scanning laser according to claim 1, characterized in that: The reference fiber interferometer (5) comprises a fifth fiber coupler (35), a first Faraday rotation mirror (121), a second Faraday rotation mirror (122) and a delay fiber (13); The third path of laser light outputted by the second optical fiber coupler (32) is inputted into the first port of the fifth optical fiber coupler (35); the third port of the fifth optical fiber coupler (35) is connected to the first Faraday rotation mirror (121); the fourth port of the fifth optical fiber coupler (35) is connected to the second Faraday rotation mirror (122) via the delay optical fiber (13); and the second port of the fifth optical fiber coupler (35) serves as the output port of the reference optical fiber interferometer (5).

4. The spectrum splicing device of wavelength segmented continuous scanning laser according to claim 1, characterized in that: The continuous scanning spectrum range of the semiconductor tunable laser (1) is ≥100 GHz, and there is an optical frequency overlap of ≥5 GHz in adjacent optical bands, and the laser line width is ≤1 MHz; The semiconductor tunable laser (1) is a DBR tunable laser or a DFB laser; The reference fiber interferometer (5) is a fiber Michelson interferometer, and the difference in interferometer arm length is ≥ 1 m.

5. The spectrum splicing device of wavelength segmented continuous scanning laser according to claim 1, characterized in that: The free spectral range of the optical fiber thermal stability etalon (6) is ≤100 GHz and the finesse is ≥7.

6. A spectrum splicing method for wavelength segmented continuous scanning laser, characterized in that: The method is implemented by using the spectrum splicing device according to any one of claims 1 to 5, comprising: The laser waveband output by the semiconductor tunable laser (1) is denoted as R waveband, and the periodic signal of equal optical wave frequency after photoelectric conversion received by the data acquisition and processing module (9) includes R waveband periodic signals, wherein the sampling length of the rth waveband periodic signal is N r , the number of cycles is M r , r=1...R, the length of the reference optical fiber interferometer (5) is l; the beat frequency interference signal of the optical fiber measurement module and the wavelength reference signal received by the data acquisition and processing module (9) after the photoelectric conversion are both segmented signals, respectively including R segment signals corresponding to the R segment waveband; S1 according to N r 、M r The optical frequency width Δν of the rth band is calculated by r , and according to the optical frequency width Δν of the rth band r Get the optical frequency step length δν of the rth band r , r=1……R; S2 resamples the beat frequency interference signal and the wavelength reference signal of the optical fiber measurement module after photoelectric conversion according to the periodic signal of equal light wave frequency after photoelectric conversion to obtain the beat frequency interference resampled signal and the wavelength reference resampled signal of the optical fiber measurement module; S3 obtains the peak position i of the rth segment signal in the wavelength reference resampled signal r,p and the optical frequency ν corresponding to the peak position r,p , r=1……R; S4 According to N r 、i r,p , ν r,p and δν r Calculate the starting point of the optical frequency ν of the rth band r,0 and optical frequency end point ν r,N ; S5 takes the optical frequency end point ν of the r-1th band r-1,N and the optical frequency starting point ν of the rth band r,0 The midpoint ν r ' ,0 As a splicing point, the r-1th signal and the rth signal in the beat frequency interference resampling signal of the optical fiber measurement module are spliced, where r=2...R; S6 repeats S1 to S5 to obtain the beat frequency interference resampling signal of the full-band optical fiber measurement module after the splicing is completed.

7. The spectrum splicing method of wavelength segmented continuous scanning laser according to claim 6, characterized in that: In S1, the optical frequency width of the rth band The optical frequency step length of the rth band Where c is the speed of light in a vacuum and n is the effective refractive index of the optical fiber.

8. The spectrum splicing method of wavelength segmented continuous scanning laser according to claim 6, characterized in that: In S3, the peak position i of the rth segment signal in the wavelength reference resampled signal is obtained. r,p Then, consult the fiber thermal stability etalon product manual to obtain the optical frequency ν corresponding to the peak position. r,p .

9. The spectrum splicing method of wavelength segmented continuous scanning laser according to claim 6, characterized in that: In S4, the starting point of the optical frequency of the rth band is ν r,0 =v r,p -i r,p δν r ; The optical frequency end point ν of the rth band r,N =v r,p +(N r -i r,p )δν r .

10. The spectrum splicing method of wavelength segmented continuous scanning laser according to claim 6, characterized in that: S2 The specific method for resampling the beat frequency interference signal and wavelength reference signal of the optical fiber measurement module after photoelectric conversion according to the periodic signal of equal optical wave frequency after photoelectric conversion is to extract the positions of the peak points, half-peak points and trough points of the periodic signal of equal optical wave frequency, resample the beat frequency interference signal and wavelength reference signal of the optical fiber measurement module at the positions of the peak points, half-peak points and trough points to obtain resampled data, and then rearrange the resampled data at equal intervals to obtain the beat frequency interference resampled signal and wavelength reference resampled signal of the optical fiber measurement module.

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