阅读说明：本技术 一种温度、应变、振动一体化的光纤传感装置 (Temperature, strain and vibration integrated optical fiber sensing device ) 是由 王宇 白卫东 靳宝全 高妍 张红娟 白清 刘昕 于 2021-09-09 设计创作，主要内容包括：本发明一种温度、应变、振动一体化的光纤传感装置,属于分布式光纤传感技术领域；所要解决的技术问题为：提供一种温度、应变、振动一体化的光纤传感装置硬件结构的改进；解决上述技术问题采用的技术方案为：通过并联窄带滤波-级联放大模块,将中心波长为1550nm的Φ-OTDR、中心波长为1450nm和1660nm的R-OTDR以及中心波段在1550nm附近的B-OTDR结合,从而实现对光纤中温度、应变和振动三参量同时分布式传感检测；通过信号发生器分时强弱电压驱动的方式驱动声光调制器,进而产生高低峰值功率周期性相间的脉冲激光,利用这种时分复用的方式,避免光纤中后向瑞利散射信号、布里渊散射信号与拉曼散射信号间的相互干扰,实现Φ-OTDR、B-OTDR与R-OTDR三者的有效协调运行；本发明应用于分布式测量。(The invention relates to a temperature, strain and vibration integrated optical fiber sensing device, belonging to the technical field of distributed optical fiber sensing; the technical problem to be solved is as follows: the improvement of the hardware structure of the optical fiber sensing device integrating temperature, strain and vibration is provided; the technical scheme for solving the technical problems is as follows: through a parallel narrow-band filtering-cascade amplification module, a phi-OTDR with the central wavelength of 1550nm, an R-OTDR with the central wavelengths of 1450nm and 1660nm and a B-OTDR with the central wave band near 1550nm are combined, so that the simultaneous distributed sensing detection of three parameters of temperature, strain and vibration in the optical fiber is realized; the acousto-optic modulator is driven by a signal generator in a time-sharing strong and weak voltage driving mode, so that pulse lasers with high and low peak power periodically alternate are generated, mutual interference among backward Rayleigh scattering signals, Brillouin scattering signals and Raman scattering signals in optical fibers is avoided by utilizing the time division multiplexing mode, and effective coordinated operation of phi-OTDR, B-OTDR and R-OTDR is realized; the invention is applied to distributed measurement.)

1. The utility model provides a temperature, strain, vibration integrated fiber sensing device which characterized in that: comprises a pulse laser generating module, a time-controlled second-order distributed random laser amplifying and time-controlled first-order distributed Raman amplifying module, a parallel narrow-band filtering-cascading amplifying module and a data acquisition and analysis module, the pulse laser generation module generates pulse detection laser with high and low peak power periodically alternated by a 1550nm narrow linewidth laser (1) in a time-sharing strong and weak voltage driving mode, the high-peak power pulse laser is used for exciting backward Raman scattering signals with central wavelengths of 1450nm and 1660nm in the single-mode optical fiber of the time-controlled second-order distributed random laser amplification and time-controlled first-order distributed Raman amplification module, and the low-peak power pulse laser is used for exciting backward Rayleigh scattering signals with central wavelengths of 1550nm and backward Brillouin scattering signals with wavelengths near 1550nm in the single-mode optical fiber of the time-controlled second-order distributed random laser amplification and time-controlled first-order distributed Raman amplification module;

the parallel narrow-band filtering-cascade amplifying module is used for dividing the returned back scattering signals into different wave bands containing 1450nm, 1550nm and 1660nm, respectively acquiring signals of different wave bands to the data acquisition and analysis module, and respectively acquiring external vibration, strain and temperature information through phi-OTDR, B-OTDR and R-OTDR.

2. A temperature, strain and vibration integrated optical fiber sensing device according to claim 1, wherein: the pulse laser generation module comprises a 1550nm narrow linewidth laser (1), the 1550nm narrow linewidth laser (1) emits continuous narrow linewidth laser with the central wavelength of 1550nm, the continuous narrow linewidth laser is input to an input end of a first optical fiber coupler (2), the first optical fiber coupler (2) divides the 1550nm laser into two parts, one part of the laser is output from a port b of the first optical fiber coupler (2) as probe light, and the other part of the laser is output from a port c of the first optical fiber coupler (2) as local light; the c output end of the first optical fiber coupler (2) is connected to the a input end of the third optical fiber coupler (19);

the detection light output from the port b of the first optical fiber coupler (2) is input to the input end a of the acousto-optic modulator (3), the signal generator (4) is connected with the input end c of the acousto-optic modulator (3), and the acousto-optic modulator (3) is driven in a time-sharing strong and weak voltage driving mode, so that pulse detection laser with high and low peak power periodically alternated is generated;

the acousto-optic modulator (3) modulates 1550nm continuous detection light into pulse light under the drive of the signal generator (4) and generates a frequency shift of 200 MHz; the modulated detection pulse light is input to the input end of a first erbium-doped fiber amplifier (5) from the output end b of the acousto-optic modulator (3), the first erbium-doped fiber amplifier (5) amplifies 1550nm pulse laser, and the amplified pulse laser is input to the input end a of a circulator (6) from the output end of the first erbium-doped fiber amplifier (5).

3. A temperature, strain and vibration integrated optical fiber sensing device according to claim 2, wherein: the time-controlled second-order distributed random laser amplification and time-controlled first-order distributed Raman amplification module comprises a second optical fiber coupler (7), a first sensing optical fiber (8), an optical fiber to be detected (9), a second sensing optical fiber (10), a wavelength division multiplexer (11), a 1455nm pump light source (12), a first semiconductor optical amplifier (13), a first optical isolator (14), a 1366nm pump light source (15), a second semiconductor optical amplifier (16), a second optical isolator (17) and a third optical isolator (18);

1550nm pulse laser is input from the b output end of the circulator (6) to the b input end of the second optical fiber coupler (7), and then is input from the c output end of the second optical fiber coupler (7) to the input end of the first sensing optical fiber (8); 1550nm pulse laser output from the output end of the first sensing optical fiber (8) is input to the input end of the optical fiber (9) to be detected, and temperature, strain and vibration signals are applied to the optical fiber (9) to be detected for system detection and identification; 1550nm pulse laser output from an optical fiber (9) to be detected is input to an input end of a second sensing optical fiber (10), wherein the first sensing optical fiber (8), the optical fiber (9) to be detected and the second sensing optical fiber (10) are all single-mode optical fibers; the 1550nm pulse laser output from the output end of the second sensing optical fiber (10) is input to the input end a of the wavelength division multiplexer (11), and is input to the input end of a third optical isolator (18) from the output end c of the wavelength division multiplexer (11);

the output end of the 1455nm pump light source (12) is connected to the input end of a first semiconductor optical amplifier (13), and the first semiconductor optical amplifier (13) periodically controls the on-off of the 1455nm pump light source (12); the output of the first semiconductor optical amplifier (13) is connected to the input of a first optical isolator (14); the output end of the first optical isolator (14) is connected to the b input end of the wavelength division multiplexer (11);

the output end of the 1366nm pump light source (15) is connected to the input end of a second semiconductor optical amplifier (16), and the second semiconductor optical amplifier (16) periodically controls the on-off of the 1366nm pump light source (15); the output end of the second semiconductor optical amplifier (16) is connected to the input end of a second optical isolator (17); the output end of the second optical isolator (17) is connected to the a input end of the second optical fiber coupler (7); the b input end of the second optical fiber coupler (7) is connected to the b output end of the circulator (6).

4. A temperature, strain and vibration integrated optical fiber sensing device according to claim 3, wherein: the parallel narrow-band filtering-cascading amplification module comprises a fourth optical fiber coupler (20), a first optical filter (21), a second erbium-doped optical fiber amplifier (22), a second optical filter (23), a third erbium-doped optical fiber amplifier (24), a third optical filter (25), a fourth erbium-doped optical fiber amplifier (26), a fourth optical filter (27) and a fifth erbium-doped optical fiber amplifier (28);

the c output end of the circulator (6) is connected to the a input end of a fourth optical fiber coupler (20), the b output end of the fourth optical fiber coupler (20) is connected to the input end of the first optical filter (21), the c output end of the fourth optical fiber coupler (20) is connected to the input end of the second optical filter (23), the d output end of the fourth optical fiber coupler (20) is connected to the input end of the third optical filter (25), and the e output end of the fourth optical fiber coupler (20) is connected to the input end of the fourth optical filter (27);

the output end of the first optical filter (21) is connected to the input end of a second erbium-doped fiber amplifier (22); the output end of the second erbium-doped fiber amplifier (22) is connected to the a input end of a fifth fiber coupler (32);

the output end of the second optical filter (23) is connected to the input end of a third erbium-doped fiber amplifier (24); the output end of the third erbium-doped fiber amplifier (24) is connected to the a input end of the first photoelectric detector (29);

the output end of the third optical filter (25) is connected to the input end of a fourth erbium-doped fiber amplifier (26); the output end of the fourth erbium-doped fiber amplifier (26) is connected to the b input end of the first photoelectric detector (29);

the output end of the fourth optical filter (27) is connected to the input end of a fifth erbium-doped fiber amplifier (28); the output end of the fifth erbium-doped fiber amplifier (28) is connected to the b input end of a sixth fiber coupler (36).

5. A temperature, strain and vibration integrated optical fiber sensing device according to claim 4, wherein: the data acquisition and analysis module comprises a first data acquisition card (30), a second data acquisition card (35), a third data acquisition card (38) and a computer (39);

the output end b of the third optical fiber coupler (19) is connected to the input end a of the sixth optical fiber coupler (36), and the output end c of the third optical fiber coupler (19) is connected to the input end of the polarization scrambler (31);

the output end of the polarization scrambler (31) is connected to the b input end of a fifth optical fiber coupler (32); the c output end of the fifth optical fiber coupler (32) is connected to the input end of a second photoelectric detector (33); the output end of the second photoelectric detection electric appliance (33) is connected to the input end of the wave detector (34); the output end of the detector (34) is connected to the input end of a second data acquisition card (35); the output end of the second data acquisition card (35) is connected to the input end a of the computer (39);

the c output end of the first photoelectric detector (29) is connected to the a input end of the first data acquisition card (30), and the d output end of the first photoelectric detector (29) is connected to the b input end of the first data acquisition card (30); the c output end of the first data acquisition card (30) is connected to the b input end of the computer (39);

the c output end of the sixth optical fiber coupler (36) is connected to the a input end of the third photoelectric detector (37), and the d output end of the sixth optical fiber coupler (36) is connected to the b input end of the third photoelectric detector (37); the c output end of the third photoelectric detector (37) is connected to the input end of a third data acquisition card (38); the output of the third data acquisition card (38) is connected to the c input of a computer (39).

Technical Field

The invention discloses a temperature, strain and vibration integrated optical fiber sensing device, and belongs to the technical field of distributed optical fiber sensing.

Background

In recent years, sensing technology has been receiving attention from more and more researchers, and various sensors have been widely used in various industrial fields. Optical fiber sensing, as a novel sensing technology, is favored by researchers in various countries in the world by virtue of its unique advantages of small size, light weight, high transmission speed, corrosion resistance, no electromagnetic interference, low cost and the like. The optical fiber sensing technology utilizes the characteristics of the amplitude, phase, polarization state, wavelength and the like of optical signals transmitted in optical fibers, which are sensitive to parameters of external physical quantities such as temperature, pressure, vibration and the like, and obtains external information quantities through a series of demodulation technical means. The optical fiber is used as a transmission medium and a sensing medium, so that full-distributed sensing can be realized, and the optical fiber has the advantage that the traditional electric sensor cannot be replaced.

With the continuous improvement of the practical application requirements of engineering, people no longer satisfy the sensing detection of only a single physical quantity but hope to obtain more external parameter information at the same time, wherein temperature, strain and vibration are the most basic and extremely important three parameters, and the research on the sensing technology of multi-parameter simultaneous distributed measurement becomes a big problem in the optical fiber sensing technology. On one hand, the multi-parameter real-time measurement puts higher requirements on the consistency of the laser, wherein the Raman optical time domain reflectometer (R-OTDR) technology requires high enough fiber-entering optical power, the phase-sensitive optical time domain reflectometer (phi-OTDR) technology and the Brillouin optical time domain reflectometer (B-OTDR) technology require the use of a narrow-linewidth laser, and for the narrow-linewidth laser, the excessively high fiber-entering optical power can generate larger nonlinear effect influence on a backward Rayleigh scattering signal and a Brillouin scattering signal in an optical fiber, and the fast attenuation of the scattering signal is mainly expressed; on the other hand, various multiplexing technologies and light splitting technologies used for multi-parameter real-time measurement provide higher signal-to-noise ratio requirements for backscattered light signals in optical fibers, and the traditional optical amplification scheme can cause uneven amplification of the light signals and can generate higher noise coefficients, thereby seriously affecting the detection of the backscattered signals.

Therefore, the invention provides a method for combining a parallel narrow-band filtering-cascade amplification structure with time-sharing strong and weak voltage driving on the basis of a narrow-line width laser, which realizes the fusion of three systems on the same single-mode fiber, constructs a structure combining time-controlled second-order distributed random laser amplification and time-controlled first-order distributed Raman amplification, and uniformly amplifies optical signals in all the fibers in a distributed manner, thereby realizing the simultaneous distributed sensing detection of three parameters of external temperature, strain and vibration, having wide market application space and having important significance on the research of novel optical fiber sensing technology.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to solve the technical problems that: the improved hardware structure of the optical fiber sensing device integrating temperature, strain and vibration is provided.

In order to solve the technical problems, the invention adopts the technical scheme that: an optical fiber sensing device integrating temperature, strain and vibration comprises a pulse laser generation module, a time-controlled second-order distributed random laser amplification and time-controlled first-order distributed Raman amplification module, a parallel narrow-band filtering-cascade amplification module and a data acquisition and analysis module, wherein the pulse laser generation module generates pulse detection laser with high and low peak power periodically alternated by adopting a time-sharing strong and weak voltage driving mode through a 1550nm narrow-line-width laser, the high-peak-power pulse laser is used for exciting backward Raman scattering signals with central wavelengths of 1450nm and 1660nm in a single-mode optical fiber of the time-controlled second-order distributed random laser amplification and time-controlled first-order distributed Raman amplification module, and the low-peak-power pulse laser is used for exciting backward Rayleigh scattering signals with the central wavelength of 1550nm and backward Brillouin scattering signals with the wavelength near 1550nm in the single-mode optical fiber of the time-controlled second-order distributed random laser amplification and time-controlled first-order distributed Raman amplification module;

the parallel narrow-band filtering-cascade amplifying module is used for dividing the returned back scattering signals into different wave bands containing 1450nm, 1550nm and 1660nm, respectively acquiring signals of different wave bands to the data acquisition and analysis module, and respectively acquiring external vibration, strain and temperature information through phi-OTDR, B-OTDR and R-OTDR.

The pulse laser generation module comprises a 1550nm narrow linewidth laser, the 1550nm narrow linewidth laser emits continuous narrow linewidth laser with the central wavelength of 1550nm and is input to an input end of a first optical fiber coupler, the first optical fiber coupler divides the 1550nm laser into two parts, one part of the laser is output from a port b of the first optical fiber coupler as probe light, and the other part of the laser is output from a port c of the first optical fiber coupler as local light; the c output end of the first optical fiber coupler is connected to the a input end of the third optical fiber coupler;

the detection light output from the port b of the first optical fiber coupler is input to the input end a of the acousto-optic modulator, the signal generator is connected with the input end c of the acousto-optic modulator and drives the acousto-optic modulator in a time-sharing strong and weak voltage driving mode, and therefore pulse detection laser with high and low peak power periodically alternated is generated;

the acousto-optic modulator is driven by the signal generator to modulate 1550nm continuous detection light into pulse light and generate 200MHz frequency shift; the modulated detection pulse light is input to the input end of a first erbium-doped fiber amplifier from the output end b of the acousto-optic modulator, the first erbium-doped fiber amplifier amplifies 1550nm pulse laser, and the amplified pulse laser is input to the input end a of the circulator from the output end of the first erbium-doped fiber amplifier.

The time-controlled second-order distributed random laser amplification and time-controlled first-order distributed Raman amplification module comprises a second optical fiber coupler, a first sensing optical fiber, an optical fiber to be detected, a second sensing optical fiber, a wavelength division multiplexer, a 1455nm pump light source, a first semiconductor optical amplifier, a first optical isolator, a 1366nm pump light source, a second semiconductor optical amplifier, a second optical isolator and a third optical isolator;

1550nm pulse laser is input from the b output end of the circulator to the b input end of the second optical fiber coupler, and then input from the c output end of the second optical fiber coupler to the input end of the first sensing optical fiber; 1550nm pulse laser output from the output end of the first sensing optical fiber is input to the input end of the optical fiber to be detected, and temperature, strain and vibration signals are applied to the optical fiber to be detected for system detection and identification; 1550nm pulse laser output from an optical fiber to be detected is input to an input end of a second sensing optical fiber, wherein the first sensing optical fiber, the optical fiber to be detected and the second sensing optical fiber are single-mode optical fibers; the 1550nm pulse laser output from the output end of the second sensing optical fiber is input to the input end a of the wavelength division multiplexer, and is input to the input end of the third optical isolator from the output end c of the wavelength division multiplexer;

the output end of the 1455nm pump light source is connected to the input end of a first semiconductor optical amplifier, and the first semiconductor optical amplifier periodically controls the on-off of the 1455nm pump light source; the output end of the first semiconductor optical amplifier is connected to the input end of a first optical isolator; the output end of the first optical isolator is connected to the b input end of the wavelength division multiplexer;

the output end of the 1366nm pump light source is connected to the input end of the second semiconductor optical amplifier, and the second semiconductor optical amplifier periodically controls the on-off of the 1366nm pump light source; the output end of the second semiconductor optical amplifier is connected to the input end of a second optical isolator; the output end of the second optical isolator is connected to the a input end of the second optical fiber coupler; and the b input end of the second optical fiber coupler is connected to the b output end of the circulator.

The parallel narrow-band filtering-cascading amplification module comprises a fourth optical fiber coupler, a first optical filter, a second erbium-doped optical fiber amplifier, a second optical filter, a third erbium-doped optical fiber amplifier, a third optical filter, a fourth erbium-doped optical fiber amplifier, a fourth optical filter and a fifth erbium-doped optical fiber amplifier;

the output end c of the circulator is connected to the input end a of a fourth optical fiber coupler, the output end b of the fourth optical fiber coupler is connected to the input end of the first optical filter, the output end c of the fourth optical fiber coupler is connected to the input end of the second optical filter, the output end d of the fourth optical fiber coupler is connected to the input end of the third optical filter, and the output end e of the fourth optical fiber coupler is connected to the input end of the fourth optical filter;

the output end of the first optical filter is connected to the input end of the second erbium-doped fiber amplifier; the output end of the second erbium-doped fiber amplifier is connected to the a input end of the fifth fiber coupler;

the output end of the second optical filter is connected to the input end of a third erbium-doped fiber amplifier; the output end of the third erbium-doped fiber amplifier is connected to the a input end of the first photoelectric detector;

the output end of the third optical filter is connected to the input end of a fourth erbium-doped fiber amplifier; the output end of the fourth erbium-doped fiber amplifier is connected to the b input end of the first photoelectric detector;

the output end of the fourth optical filter is connected to the input end of a fifth erbium-doped fiber amplifier; and the output end of the fifth erbium-doped fiber amplifier is connected to the b input end of the sixth fiber coupler.

The data acquisition and analysis module comprises a first data acquisition card, a second data acquisition card, a third data acquisition card and a computer;

the output end b of the third optical fiber coupler is connected to the input end a of the sixth optical fiber coupler, and the output end c of the third optical fiber coupler is connected to the input end of the polarization scrambler;

the output end of the polarization scrambler is connected to the b input end of a fifth optical fiber coupler; the c output end of the fifth optical fiber coupler is connected to the input end of the second photoelectric detector; the output end of the second photoelectric detection electric appliance is connected to the input end of the detector; the output end of the detector is connected to the input end of the second data acquisition card; the output end of the second data acquisition card is connected to the input end a of the computer;

the output end c of the first photoelectric detector is connected to the input end a of the first data acquisition card, and the output end d of the first photoelectric detector is connected to the input end b of the first data acquisition card; the output end c of the first data acquisition card is connected to the input end b of the computer;

the output end c of the sixth optical fiber coupler is connected to the input end a of the third photoelectric detector, and the output end d of the sixth optical fiber coupler is connected to the input end b of the third photoelectric detector; the output end c of the third photoelectric detector is connected to the input end of a third data acquisition card; and the output end of the third data acquisition card is connected to the c input end of the computer.

Compared with the prior art, the invention has the beneficial effects that:

the invention designs a parallel narrow-band filtering-cascade amplification structure, which divides backward scattering light in an optical fiber into bands of 1450nm, 1550nm and 1660nm, and combines a phi-OTDR technology with the central wavelength of 1550nm, an R-OTDR technology with the central wavelengths of 1450nm and 1660nm and a B-OTDR technology with the central band near 1550nm, thereby realizing the simultaneous distributed sensing detection of three parameters of temperature, strain and vibration in the optical fiber.

The acousto-optic modulator is driven by a signal generator in a time-sharing strong and weak voltage driving mode by utilizing a time-division multiplexing mode, and then pulse detection laser with high and low peak power periodically alternated is generated. The high-peak power pulse laser is used for exciting backward Raman scattering signals in the single-mode fiber, the low-peak power pulse laser is used for exciting backward Rayleigh scattering signals and Brillouin scattering signals in the single-mode fiber, mutual interference among various backward scattering signals is avoided, and efficient coordinated operation of the phi-OTDR technology, the B-OTDR technology and the R-OTDR technology is achieved.

The invention constructs a structure combining time-controlled second-order distributed random laser amplification and time-controlled first-order distributed Raman amplification, avoids the problems of spontaneous noise accumulation, nonlinear damage and the like caused by the traditional optical amplification mode, solves the structural conflict between the general distributed bidirectional amplification and the R-OTDR technology, achieves the effect of outputting the full spectrum of the back scattering light, realizes the distributed uniform amplification of optical signals in the optical fiber, reduces the system noise coefficient, and further realizes the performance indexes of longer sensing distance, higher signal-to-noise ratio, higher spatial resolution and the like.

Drawings

The invention is further described below with reference to the accompanying drawings:

FIG. 1 is a schematic structural view of the present invention;

in the figure: 1. a 1550nm narrow linewidth laser; 2. a first fiber coupler; 3. an acousto-optic modulator; 4. a signal generator; 5. a first erbium-doped fiber amplifier; 6. a circulator; 7. a second fiber coupler; 8. a first sensing optical fiber; 9. an optical fiber to be tested; 10. a second sensing optical fiber; 11. a wavelength division multiplexer; 12. 1455nm pump light source; 13. a first semiconductor optical amplifier; 14. a first optical isolator; 15. 1366nm pump light source; 16. a second semiconductor optical amplifier; 17. a second optical isolator; 18. a third optical isolator; 19. a third fiber coupler; 20. a fourth fiber coupler; 21. a first optical filter; 22. a second erbium-doped fiber amplifier; 23. a second optical filter; 24. a third erbium-doped fiber amplifier; 25. a third optical filter; 26. a fourth erbium-doped fiber amplifier; 27. a fourth optical filter; 28. a fifth erbium-doped fiber amplifier; 29. a first photodetector; 30. a first data acquisition card; 31. a deflection scrambler; 32. a fifth fiber coupler; 33. a second photodetector; 34. a detector; 35. a second data acquisition card; 36. a sixth fiber coupler; 37. a third photodetector; 38. a third data acquisition card; 39. and (4) a computer.

Detailed Description

As shown in FIG. 1, the temperature, strain and vibration integrated optical fiber sensing device of the present invention comprises a 1550nm narrow linewidth laser 1, a first optical fiber coupler 2, an acousto-optic modulator 3, a signal generator 4, a first erbium-doped optical fiber amplifier 5, a circulator 6, a second optical fiber coupler 7, a first sensing optical fiber 8, a fiber 9 to be measured, a second sensing optical fiber 10, a wavelength division multiplexer 11, a 1455nm pump light source 12, a first semiconductor optical amplifier 13, a first optical isolator 14, a 1366nm pump light source 15, a second semiconductor optical amplifier 16, a second optical isolator 17, a third optical isolator 18, a third optical fiber coupler 19, a fourth optical fiber coupler 20, a first optical filter 21, a second erbium-doped optical fiber amplifier 22, a second optical filter 23, a third erbium-doped optical fiber amplifier 24, a third optical filter 25, a fourth erbium-doped optical fiber amplifier 26, a fourth optical filter 27, A fifth erbium-doped fiber amplifier 28, a first photodetector 29, a first data acquisition card 30, a polarization scrambler 31, a fifth fiber coupler 32, a second photodetector 33, a detector 34, a second data acquisition card 35, a sixth fiber coupler 36, a third photodetector 37, a third data acquisition card 38 and a computer 39. Fig. 1 is a schematic structural diagram of an integrated optical fiber sensing device for temperature, strain and vibration according to the present invention, and the following describes an embodiment of the present invention with reference to fig. 1.

Wherein, the output end of the 1550nm narrow linewidth laser 1 is connected to the a input end of the first optical fiber coupler 2; the output end b of the first optical fiber coupler 2 is connected to the input end a of the acousto-optic modulator 3, and the output end c of the first optical fiber coupler 2 is connected to the input end a of the third optical fiber coupler 19; the output end b of the acousto-optic modulator 3 is connected to the input end of a first erbium-doped fiber amplifier 5; the output end of the signal generator 4 is connected to the input end c of the acousto-optic modulator 3, and pulse signals with high and low peak power periodically alternated are provided for the acousto-optic modulator 3; the output end of the first erbium-doped fiber amplifier 5 is connected to the a input end of a circulator 6; the b output end of the circulator 6 is connected to the b input end of the second optical fiber coupler 7, and the c output end of the circulator 6 is connected to the a input end of the fourth optical fiber coupler 20; the output end c of the second optical fiber coupler 7 is connected to the input end a of the wavelength division multiplexer 11 after sequentially passing through the first sensing optical fiber 8, the optical fiber 9 to be tested and the second sensing optical fiber 10; the output end of the 1455nm pump light source 12 is connected to the input end of the first semiconductor optical amplifier 13, and the first semiconductor optical amplifier 13 periodically controls the on-off of the 1455nm pump light source 12; the output of the first semiconductor optical amplifier 13 is connected to the input of a first optical isolator 14; the output end of the first optical isolator 14 is connected to the b input end of the wavelength division multiplexer 11; the c output of the wavelength division multiplexer 11 is connected to the input of a third optical isolator 18; the output end of the 1366nm pump light source 15 is connected to the input end of the second semiconductor optical amplifier 16, and the second semiconductor optical amplifier 16 periodically controls the on-off of the 1366nm pump light source 15; the output of the second semiconductor optical amplifier 16 is connected to the input of a second optical isolator 17; the output end of the second optical isolator 17 is connected to the a input end of the second optical fiber coupler 7; the b output end of the third optical fiber coupler 19 is connected to the a input end of the sixth optical fiber coupler 36, and the c output end of the third optical fiber coupler 19 is connected to the input end of the polarization scrambler 31; the b output end of the fourth optical fiber coupler 20 is connected to the input end of the first optical filter 21, the c output end of the fourth optical fiber coupler 20 is connected to the input end of the second optical filter 23, the d output end of the fourth optical fiber coupler 20 is connected to the input end of the third optical filter 25, and the e output end of the fourth optical fiber coupler 20 is connected to the input end of the fourth optical filter 27; the output end of the first optical filter 21 is connected to the input end of a second erbium-doped fiber amplifier 22; the output end of the second erbium-doped fiber amplifier 22 is connected to the a input end of a fifth fiber coupler 32; the output end of the polarization scrambler 31 is connected to the b input end of a fifth optical fiber coupler 32; the c output end of the fifth optical fiber coupler 32 is connected to the input end of the second photodetector 33; the output end of the second photoelectric detection device 33 is connected to the input end of the wave detector 34; the output end of the detector 34 is connected to the input end of a second data acquisition card 35; the output end of the second data acquisition card 35 is connected to the a input end of the computer 39; the output end of the second optical filter 23 is connected to the input end of a third erbium-doped fiber amplifier 24; the output end of the third erbium-doped fiber amplifier 24 is connected to the a input end of the first photodetector 29; the output end of the third optical filter 25 is connected to the input end of a fourth erbium-doped fiber amplifier 26; the output end of the fourth erbium-doped fiber amplifier 26 is connected to the b input end of the first photodetector 29; the output end c of the first photodetector 29 is connected to the input end a of the first data acquisition card 30, and the output end d of the first photodetector 29 is connected to the input end b of the first data acquisition card 30; the c output end of the first data acquisition card 30 is connected to the b input end of the computer 39; the output end of the fourth optical filter 27 is connected to the input end of a fifth erbium-doped fiber amplifier 28; the output end of the fifth erbium-doped fiber amplifier 28 is connected to the b input end of a sixth fiber coupler 36; the c output end of the sixth optical fiber coupler 36 is connected to the a input end of the third photodetector 37, and the d output end of the sixth optical fiber coupler 36 is connected to the b input end of the third photodetector 37; the output c of said third photodetector 37 is connected to the input of a third data acquisition card 38; the output of said third data acquisition card 38 is connected to the c input of a computer 39.

The 1550nm narrow linewidth laser 1 emits continuous narrow linewidth laser with a central wavelength of 1550nm, and the continuous narrow linewidth laser is input to an input end of the first optical fiber coupler 2, the first optical fiber coupler 2 divides the 1550nm laser into two parts, namely 90% laser and 10% laser, the 90% laser is output from a port b of the first optical fiber coupler 2 as detection light, and the 10% laser is output from a port c of the first optical fiber coupler 2 as local light; the detection light output from the port b of the first optical fiber coupler 2 is input to the input end a of the acousto-optic modulator 3, the signal generator 4 is connected with the input end c of the acousto-optic modulator 3, and drives the acousto-optic modulator 3 by time-sharing strong and weak voltage driving, so as to generate pulse detection laser with high and low peak power periodically alternated, wherein the high peak power pulse laser is used for exciting backward Raman scattering signals with central wavelengths of 1450nm and 1660nm in the single-mode optical fiber, the low peak power pulse laser is used for exciting backward Rayleigh scattering signals with central wavelengths of 1550nm and backward Brillouin scattering signals with wavelengths near 1550nm in the single-mode optical fiber, and the mutual interference among multiple backward scattering signals in the optical fiber is effectively avoided by the time-division multiplexing mode; the acousto-optic modulator 3 modulates 1550nm continuous probe light into pulse light under the drive of the signal generator 4 and generates a frequency shift of 200 MHz; the modulated detection pulse light is input to the input end of the first erbium-doped fiber amplifier 5 from the output end b of the acousto-optic modulator 3, and the first erbium-doped fiber amplifier 5 amplifies 1550nm pulse laser; the amplified pulse laser is input to the input end a of the circulator 6 from the output end of the first erbium-doped fiber amplifier 5; 1550nm pulse laser light is input from the b output end of the circulator 6 to the b input end of the second optical fiber coupler 7, and then is input from the c output end of the second optical fiber coupler 7 to the input end of the first sensing optical fiber 8; 1550nm pulse laser output from the output end of the first sensing optical fiber 8 is input to the input end of the optical fiber 9 to be detected, and temperature, strain and vibration signals are applied to the optical fiber 9 to be detected for system detection and identification; 1550nm pulse laser output from an optical fiber to be detected 9 is input to an input end of a second sensing optical fiber 10, and the first sensing optical fiber 8, the optical fiber to be detected 9 and the second sensing optical fiber 10 are all single-mode optical fibers; the 1550nm pulse laser light output from the output end of the second sensing optical fiber 10 is input to the a input end of the wavelength division multiplexer 11, and is input from the c output end of the wavelength division multiplexer 11 to the input end of the third optical isolator 18, and the third optical isolator 18 is used for preventing the reflected laser light from affecting the backscattered signal.

The 1455nm pump light source 12, the first semiconductor optical amplifier 13, the first optical isolator 14, the 1366nm pump light source 15, the second semiconductor optical amplifier 16, the second optical isolator 17, the second optical fiber coupler 7, the first sensing optical fiber 8, the optical fiber 9 to be detected, the second sensing optical fiber 10 and the wavelength division multiplexer 11 jointly form a structure combining time-controlled second-order distributed random laser amplification and time-controlled first-order distributed raman amplification, distributed uniform amplification of all-fiber optical signals is achieved, structural conflict between general distributed bidirectional amplification and an R-OTDR technology is solved, and full-spectrum output of backscattered signals is achieved.

1455nm continuous laser output by a 1455nm pump light source 12 is input to an input end of a first semiconductor optical amplifier 13, the first semiconductor optical amplifier 13 periodically controls the on-off of the 1455nm pump light source 12, when a signal generator 4 outputs a strong voltage driving pulse signal, the first semiconductor optical amplifier 13 controls the 1455nm pump light source 12 to be switched off, and when the signal generator 4 outputs a weak voltage driving pulse signal, the first semiconductor optical amplifier 13 controls the 1455nm pump light source 12 to be switched on, so that the influence of the 1455nm laser on an anti-stokes light component with the wavelength of 1450nm in a backward Raman scattering signal excited by high-peak-power pulse laser generated by modulating the strong voltage driving pulse signal in an optical fiber is avoided; the 1455nm continuous laser light output from the first semiconductor optical amplifier 13 is input to an input terminal of a first optical isolator 14, the first optical isolator 14 is used to prevent the reflected laser light from damaging the 1455nm pump light source 12; the 1455nm continuous laser output from the first optical isolator 14 is input to a b input end of the wavelength division multiplexer 11, and then is input to the single-mode optical fiber from an a output end of the wavelength division multiplexer 11, and the 1455nm laser performs distributed first-order uniform amplification on the laser of 1550nm existing in the optical fiber, so that the optical signal in the optical fiber is enhanced.

1366nm continuous laser output by a 1366nm pump light source 15 is input to an input end of a second semiconductor optical amplifier 16, the second semiconductor optical amplifier 16 periodically controls the connection and disconnection of the 1366nm pump light source 15, when a signal generator 4 outputs a strong voltage driving pulse signal, the second semiconductor optical amplifier 16 controls the 1366nm pump light source 15 to be disconnected, when the signal generator 4 outputs a weak voltage driving pulse signal, the second semiconductor optical amplifier 16 controls the 1366nm pump light source 15 to be connected, and the purpose is to prevent the 1366nm laser from carrying out first-order amplification on an anti-stokes light component with the wavelength of 1450nm in backward Raman scattering signals excited by high-peak power pulse laser generated by modulation of the strong voltage driving pulse signal in an optical fiber, so as to influence the demodulation of temperature signals in an R-OTDR system; the 1366nm continuous laser output from the second semiconductor optical amplifier 16 is input to the input end of the second optical isolator 17, and the second optical isolator 17 is used for preventing the reflected laser from damaging the 1366nm pump light source 15; the 1366nm continuous laser output from the output end of the second optical isolator 17 is input to the input end a of the second optical fiber coupler 7, and is input to the single-mode optical fiber from the output end c of the second optical fiber coupler 7, the 1366nm laser firstly performs first-order distributed uniform amplification on the 1455nm wavelength optical signal in the random back scattering light existing in the optical fiber, and then performs second-order distributed uniform amplification on the 1550nm laser existing in the optical fiber by the amplified 1455nm laser, so that second-order amplification on the 1550nm laser in the optical fiber is realized, and the optical signal in the optical fiber is further enhanced.

In the process of transmitting the 1550nm pulse laser in the first sensing optical fiber 8, the optical fiber 9 to be detected and the second sensing optical fiber 10, random backward scattering optical signals containing multiple wavelengths are generated in the first sensing optical fiber 8, the optical fiber 9 to be detected and the second sensing optical fiber 10, and the backward scattering optical signals carry external environment information. Wherein the strong voltage drive signal of 4 launches by signal generator is through driving acousto-optic modulator 3, and then the high peak power's of modulation 1550nm pulsed laser arouses the wavelength that produces in single mode fiber to be 1450nm backscatter light and 1660nm backscatter light and carry external temperature information, and the weak voltage drive signal of 4 launches by signal generator is through driving acousto-optic modulator 3, and then the low peak power's of modulation 1550nm pulsed laser arouses the wavelength that produces in single mode fiber to be 1550nm and its near wave band backscatter light then carries external vibration and strain information. The random backward scattered light signal generated in the optical fiber is input to the c input end of the second optical fiber coupler 7, and is input to the b input end of the circulator 6 from the b output end of the second optical fiber coupler 7, and then the backward scattered light is input to the a input end of the fourth optical fiber coupler 20 from the c output end of the circulator 6.

The fourth optical fiber coupler 20, the first optical filter 21, the second erbium-doped optical fiber amplifier 22, the second optical filter 23, the third erbium-doped optical fiber amplifier 24, the third optical filter 25, the fourth erbium-doped optical fiber amplifier 26, the fourth optical filter 27 and the fifth erbium-doped optical fiber amplifier 28 form a parallel narrow-band filtering-cascading amplification structure, and are used for dividing a returned backscattered signal into different bands containing 1450nm, 1550nm and 1660nm, so that external vibration, strain and temperature information can be acquired in a phi-OTDR technology, a B-OTDR technology and an R-OTDR technology respectively.

The fourth optical fiber coupler 20 divides the input backscattered light into four parts of 25%, 25% and 25%, wherein the first part of the backscattered light is input to the input end of the first optical filter 21 from the output end b of the fourth optical fiber coupler 20, and the first optical filter 21 filters out the brillouin backscattered signals with the wavelength at 1550nm and its nearby band in the backscattered light; the brillouin backscattered signal filtered out from the first optical filter 21 is input to the input end of the second erbium-doped fiber amplifier 22, and the second erbium-doped fiber amplifier 22 is used for amplifying the brillouin backscattered light signal so as to compensate the loss of the fourth optical fiber coupler 20 caused by the light splitting action on the backscattered light signal; the amplified brillouin backscattered signal is input from the output end of the second erbium-doped fiber amplifier 22 to the a input end of the fifth fiber coupler 32; the third optical fiber coupler 19 divides the input local light into two parts of 90% and 10%, wherein 10% of the local light is input from the output end b of the third optical fiber coupler 19 to the input end a of the sixth optical fiber coupler 36, and 90% of the local light is input from the output end c of the third optical fiber coupler 19 to the input end b of the fifth optical fiber coupler 32 through the polarization scrambler 31; the two beams of light input into the fifth optical fiber coupler 32 are subjected to beat frequency in the fifth optical fiber coupler 32, and then beat frequency signals are input from the c output end of the fifth optical fiber coupler 32 to the input end of the second photodetector 33; the second photoelectric detector 33 converts the optical signal into an electrical signal, and inputs the electrical signal to the input end of the second data acquisition card 35 through the detector 34; the second data acquisition card 32 inputs the acquired signals to the input end a of the computer 39, and the computer 39 demodulates and analyzes the acquired signals and acquires strain information around the single-mode optical fiber by using the B-OTDR technique.

The second part of the backward scattering light is input to the input end of a second optical filter 23 from the c output end of the fourth optical fiber coupler 20, and the second optical filter filters out the anti-stokes backward scattering light with the wavelength of 1450nm in the raman scattering signal in the backward scattering light; 1450nm backward scattering light is input to the input end of the third erbium-doped fiber amplifier 24 from the output end of the second optical filter 23, and the third erbium-doped fiber amplifier 24 amplifies the 1450nm backward scattering light to make up for the loss of the backward scattering light caused by the light splitting effect of the fourth optical fiber coupler 20; the amplified 1450nm backscattered light is input from the output end of the third erbium-doped fiber amplifier 24 to the a input end of the first photodetector 29; a third part of the backward scattering light is input to the input end of a third optical filter 25 from the d output end of the fourth optical fiber coupler 20, and the third optical filter 25 filters out stokes backward scattering light with the wavelength of 1660nm in a raman scattering signal in the backward scattering light; 1660nm backward scattered light is input from the output end of the third optical filter 25 to the input end of the fourth erbium-doped fiber amplifier 26, and the fourth erbium-doped fiber amplifier 26 amplifies the 1660nm backward scattered light to compensate for the loss of the fourth fiber coupler 20 caused by the light splitting effect on the backward scattered light; the amplified 1660nm backscattered light is input from the output of the fourth erbium-doped fiber amplifier 26 to the b input of the first photodetector 29; the first photodetector 29 converts the optical signal into an electrical signal, wherein the electrical signal converted from the 1450nm backscattered light is input from the c output terminal of the first photodetector 29 to the a input terminal of the first data acquisition card 30, and the electrical signal converted from the 1660nm backscattered light is input from the d output terminal of the first photodetector 29 to the b input terminal of the first data acquisition card 30; the first data acquisition card 30 inputs the acquired signal to the b input terminal of the computer 39 through the c output terminal of the first data acquisition card 30; the computer 39 demodulates and analyzes the acquired signal and acquires temperature information around the single-mode optical fiber using the R-OTDR technique.

The fourth part of the backward scattered light is input into the input end of a fourth optical filter 27 from the e output end of the fourth optical fiber coupler 20, and the fourth optical filter 27 filters out rayleigh backward scattered light with the wavelength of 1550nm in the backward scattered light; the rayleigh backscattered light is input from the output end of the fourth optical filter 27 to the input end of the fifth erbium-doped fiber amplifier 28, and the fifth erbium-doped fiber amplifier 28 amplifies a rayleigh backscattered light signal of 1550nm to compensate for the loss of the backscattered light caused by the light splitting effect of the fourth optical fiber coupler 20; the amplified rayleigh backscattered signal is input from the output terminal of the fifth erbium-doped fiber amplifier 28 to the b input terminal of the sixth fiber coupler 36; the two beams of light input to the sixth fiber coupler 36 are subjected to beat frequency in the sixth fiber coupler 36; then the sixth fiber coupler 36 divides the beat frequency signal into two parts of 50% and 50%, wherein one part of the beat frequency signal is input from the c output terminal of the sixth fiber coupler 36 to the a input terminal of the third photodetector 37, and the other part of the beat frequency signal is input from the d output terminal of the sixth fiber coupler 36 to the b input terminal of the third photodetector 37; the third photodetector 37 converts the optical signal into an electrical signal, and inputs the converted electrical signal from the c output terminal of the third photodetector 37 to the input terminal of the third data acquisition card 38; the third data acquisition card 38 acquires the input signal and inputs the acquired signal from the output end of the third data acquisition card 38 to the c input end of the computer 39; the computer 39 demodulates and analyzes the acquired signal, and acquires vibration information around the single-mode optical fiber using a Φ -OTDR technique.

The invention discloses a temperature, strain and vibration integrated optical fiber sensing device, which is a device for realizing the simultaneous distributed sensing detection of three parameters of temperature, strain and vibration in an optical fiber by designing a parallel narrow-band filtering-cascade amplification structure and combining a phi-OTDR technology with the central wavelength of 1550nm, an R-OTDR technology with the central wavelengths of 1450nm and 1660nm and a B-OTDR technology with the central wave band near 1550 nm. The acousto-optic modulator is driven by the signal generator in a time-sharing strong and weak voltage driving mode, so that pulse lasers with high and low peak power periodically alternate are generated, mutual interference among backward Rayleigh scattering signals, Brillouin scattering signals and Raman scattering signals in the optical fiber is avoided by the time division multiplexing mode, and effective coordinated operation of the phi-OTDR technology, the B-OTDR technology and the OTDR technology is achieved. The structure combining time-controlled second-order distributed random laser amplification and time-controlled first-order distributed Raman amplification is constructed, the problems of spontaneous noise accumulation, nonlinear damage and the like caused by the traditional optical amplification mode are solved, the structural conflict between the general distributed bidirectional amplification and the R-OTDR technology is solved, the effect of outputting the full spectrum of the backward scattering light is achieved, the distributed uniform amplification of optical signals in the optical fiber is realized, the system noise coefficient is reduced, the loss of various multiplexing technologies and light splitting technologies to the optical signals is compensated, the signal-to-noise ratio of the optical signals in the optical fiber is improved, and further the longer sensing distance and the higher spatial resolution are realized.

It should be noted that, regarding the specific structure of the present invention, the connection relationship between the modules adopted in the present invention is determined and can be realized, except for the specific description in the embodiment, the specific connection relationship can bring the corresponding technical effect, and the technical problem proposed by the present invention is solved on the premise of not depending on the execution of the corresponding software program.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.