Wavelength phase-shifting fiber acoustic sensing array demodulating system and method
A sensor array, wavelength phase shifting technology, applied in the measurement of ultrasonic/sonic/infrasonic waves, using wave/particle radiation, measuring devices, etc., can solve the problems of limited phase shift frequency, PZT phase shift error, etc., and achieve high stability , the effect of compact structure
Active Publication Date: 2019-12-27
DALIAN UNIV OF TECH
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However, due to the nonlinearity and temperature drift of PZT, PZT phase shifting can easily cause phase shift errors
In addition, the way of mechanical phase shifting results in limited frequency of phase shifting
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[0042] The specific embodiments of the present invention are described in detail below in conjunction with the technical solutions and the accompanying drawings, but the protection scope of the present invention should not be limited by this.
[0043] see figure 1 As shown, a wavelength phase-shifted fiber optic acoustic sensing array demodulation system is constructed, here four sensing channels are included as an example. Including wavelength control and synchronous sampling module 1, fast wide tunable laser 2, 1*N fiber coupler 3, fiber circulator / 4, interferometric fiber optic acoustic sensor 5, multi-channel photodetector 6 and data processing module 7, can At the same time, the high-speed cavity-length demodulation of the interferometric fiber optic acoustic sensor array is realized.
[0044] The wavelength control and synchronous sampling module 1 is realized by FPGA, and the data processing module 7 is realized by computer; the FPGA control board realizes the fast and...
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The invention discloses a wavelength phase-shifting fiber acoustic sensing array demodulating system and method. A phase-shift interference technology is applied to fiber acoustic sensor demodulation.Phase shifting is generated by rapid switching of the wavelength. A nanosecond-grade wavelength switching speed is realized by a wide tunable laser; an interference spectrum of each sensor in an interference fiber acoustic sensing array is obtained through wavelength linear scanning; and corresponding initial cavity lengths are calculated. Five wavelengths capable of generating orthogonal phase shifting are switched according to the average cavity length. A phase-shifting step length introduced to each sensing channel by the wavelength switching can be calculated accurately, and then the real-time cavity length change is calculated through a five-step phase-shifting algorithm. An alternating current quantity for demodulating the cavity length is used for representing an acoustic signal, and a direct current quantity is used for calibrating the phase-shifting step length of each channel in real time. Through adoption of the system and method, the problem concerned with the demodulationof an existing interference fiber acoustic sensing array can be solved. A wavelength phase-shifting way is adopted to realize high-speed, large-dynamic-range and high-stability demodulation of a large-scale acoustic sensor.
Description
technical field [0001] The invention belongs to the technical field of optical fiber sensing, and for the first time proposes and constructs a wavelength phase-shifted optical fiber acoustic sensing array demodulation system, and solves the multiplexing problem of the interference type optical fiber acoustic sensor. Background technique [0002] High-performance dynamic sensing of acoustic signals has been widely used, such as non-destructive testing, photoacoustic imaging, and structural condition monitoring. Due to its compact structure, high sensitivity, anti-electromagnetic interference and remote monitoring characteristics, the interferometric fiber optic acoustic sensor is a promising acoustic sensing technology, especially in extreme temperatures, strong electromagnetic interference, etc. Use scenarios of acoustic sensors. Usually based on four basic structures: fiber Mach-Zehnder interferometer, fiber Michelson interferometer, fiber Sagnac interferometer and fiber F...
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Login to View More IPC IPC(8): G01H9/00
CPCG01H9/004
Inventor 荆振国彭伟刘强刘悦莹李昂夏振杰
Owner DALIAN UNIV OF TECH