Modified phase-generated carrier demodulation compensated for the propagation delay of the fiber

Qian, Xinlei; Kong, Yong; Du, Tongyao; Wang, Zhenwei; Ding, Wei

doi:10.1016/j.optcom.2019.124595

Cited by 15 publications

(1 citation statement)

References 24 publications

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“…Therefore, it is very important to simultaneously eliminate C and θ without LID in the PGC demodulation technique to improve the stability of the demodulation system and reduce the harmonic distortion. Some researchers have adopted many methods to remove C or θ to improve the demodulation technique, Qian et al [18] eliminates the θ by combining the PGC demodulation technology with a 3 × 3 coupler to make the harmonic carrier mix signal and the interfering signal output from interferometer simultaneously by mathematical transformation. Qu et al [19] put forward a self-calibration PGC-Arctan (PGC-Arctan-SC) algorithm which estimates the C through the ellipse parameter, and nonlinear distortion is suppressed through ellipse fitting algorithm.…”

Section: Introductionmentioning

confidence: 99%

An improved high stability and low distortion phase generated carrier demodulation algorithm for phase-sensitive optical time-domain reflectometers

Xiao¹,

Cheng²,

Zhang³

et al. 2022

Laser Phys. Lett.

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The phase generated carrier (PGC) demodulation technique for phase-sensitive optical time-domain reflectometry (Ф-OTDR) has significant potential in applications involving distributed optical fiber sensing and imaging. An improved PGC demodulation algorithm for a Ф-OTDR combined with an unbalanced Michelson interferometer system is presented in this letter. This modified PGC technique uses the one output signal as a fundamental carrier frequency signal with mathematical transformations, and another output is the modulated signal, which enable the two signals to be output synchronously from the interferometer. Theoretical simulations and experiments demonstrate that the linear and nonlinear distortion caused by phase modulation depth and carrier phase delay are well suppressed by the proposed algorithm with high stability and low distortion. The signal-to-noise-and-distortion ratio of sensors using the proposed method in the same conditions achieve gains of 12.98 dB, 30.82 dB and 6.93 dB over PGC-Arctan, PGC-differential-and-cross-multiplying and PGC-single-path differential division method, respectively. Experimental verification shows that the proposed demodulation system can exactly recover the original signals of multiple vibration positions simultaneously, and the system employing the ameliorated PGC demodulation algorithm has the noise level of about 1.83 × 10−4 rad (√Hz)−1 and a large dynamic range of 65.72 dB @ 800 Hz, which provides a new choice for distributed optical fiber sensing technology.

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Section: Introductionmentioning

confidence: 99%