Improved phase carrier PGC demodulation method and system
A technology of phase carrier and demodulation method, applied in the field of optical fiber interferometer measurement, can solve problems such as time delay asynchrony, and achieve the effect of reducing the effects of phase drift and DC drift, and reducing structural complexity
Active Publication Date: 2019-11-05
SHANGHAI SINO TELECOM TECH
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[0004] The purpose of the present invention is to provide an improved phase carrier PGC demodulation method and system, which solves the time delay and interference signal due to the analog-to-digital conversion between the carrier signal and the disturbance signal of the two arms of the MZ structure and the frequency multiplied signal The problem of out-of-synchronization occurs, and the influence of phase offset and DC drift on demodulation can be reduced
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[0045] The present invention will be described in further detail below in conjunction with the accompanying drawings.
[0046] According to one or more embodiments, such as figure 1 As shown, an improved phase-carrier PGC demodulation system, the system includes a laser that emits a laser source, a Mach-Zehnder interference structure that performs interference to output an initial disturbance signal and a carrier signal, and a 3×3 coupler. Specifically along the signal transmission direction, it includes laser light source, attenuator, coupler, piezoelectric ceramics, 3×3 coupler, photodiode, low-pass filter, and high-pass filter in sequence. Through the Mach-Zehnder interference structure, the interference signal, the fundamental frequency signal and the double frequency signal are output synchronously from the same interferometer, there is no influence of the time delay between the signals during frequency mixing, and the fundamental frequency double frequency signal is all ...
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The invention discloses an improved phase carrier PGC demodulation method and system, relates to the field of optical fiber interferometer measurement, and solves the problem that time delay and interference signals generated between carrier signals and disturbance signals of two arms of an MZ structure are not synchronous with frequency doubling signals due to analog-to-digital conversion; according to the technical scheme, based on a mach-zehnder interference structure, a 3*3 coupler is connected to the back end of an interferometer to output three paths of interference signals, wherein thetwo paths of the output signals are subjected to mathematical manipulation to serve as a fundamental frequency signal and a frequency doubling signal while the third path serves as a to-be-demodulatedsignal, so that a mixed-frequency signal and the to-be-demodulated signal are synchronously output from the middle of the interferometer, and small-signal demodulation is carried out by using a PGC demodulation inverse tangent algorithm; and according to the method and the system, two paths of mixed-frequency signals do not need to be additionally introduced in an optical path or algorithm, so that the structure complexity is reduced, and the influence of phase offset and direct-current drift on demodulation is reduced.
Description
technical field [0001] The invention relates to optical fiber interferometer measurement, in particular to an improved phase carrier PGC demodulation method and system. Background technique [0002] Optical fiber sensors have the characteristics of good stability, flexible application scenarios, and high reliability, so they are widely used in harsh environments such as high temperature, flammable, explosive, and corrosive. Among them, Mach-Zehnder, as an interferometric distributed optical fiber sensing system, is widely used in the field of perimeter security due to its advantages of high sensitivity and accurate positioning of external disturbances. At present, signal demodulation is a key research direction of optical fiber sensor system, and interferometric demodulation is one of the most commonly used demodulation methods, which includes 3×3 fiber coupler demodulation method and phase generation carrier demodulation method. The disadvantage of the 3×3 coupler is that ...
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IPC IPC(8): G01B9/02
CPCG01B9/02002
Inventor 钱心磊孔勇
Owner SHANGHAI SINO TELECOM TECH