An improved phase carrier PGC demodulation method and system
A demodulation method and phase carrier technology, applied to instruments, measuring devices, optical devices, etc., can solve problems such as time delay and asynchronous, reduce the effect of phase drift and DC drift, and reduce structural complexity
Active Publication Date: 2021-04-06
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 time delay between the carrier signal and the disturbance signal of the two arms of the MZ structure and the interference signal due to analog-to-digital conversion There will be a problem of asynchrony with the frequency multiplier signal. The main point of the technical solution is based on the Mach-Zehnder interference structure. A 3×3 coupler is connected at the back end of the interferometer to output three-way interference signals, and two of the output signals are mathematically The conversion is used as the base frequency signal and the double frequency signal, and the other is used as the signal to be demodulated, so that the mixed frequency signal and the signal to be demodulated are output synchronously from the interferometer, and the PGC demodulation arctangent algorithm is used for small signal demodulation. The method and system of the invention do not need additional introduction of the two-way mixing signal into the optical path or algorithm, which reduces the complexity of the structure and reduces the influence of phase offset and DC drift on demodulation.
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