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Proceedings Paper

A new phase generated carrier demodulation method based on fixed phase delay
Author(s): Qingping Shi; Liwei Wang; Huayong Zhang; Changdong Tian; Min Zhang; Qian Tian; Yanbiao Liao
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Paper Abstract

Phase Generated Carrier (PGC) with directly Frequency Modulation (FM) is one of the most important demodulation methods for optical fiber interferometric sensor system. Previous research has confirmed that system performance using Orthogonal Demodulation Type PGC (ODT-PGC) method is determined by many parameters, such as signal phase delay, FM depth, laser intensity accompanying modulation. This article proposes a new PGC demodulation method based on Fixed Phase Delay (FPD-PGC) by 3x2 directional coupler, using second-harmonic components of two interferometric signals to demodulate. The demodulation principle of the new method is described in detail and its performances have been studied. Theoretical analysis and experimental results show that the new method combines main advantages of directional coupler method and ODT-PGC method, and eliminates, to a great extent, the impacts of FM depth, signal phase delay, intensity modulation. Signal-to-total-Harmonic Ratio (SHR) of new method increases more than 30dB compare with ODT-PGC method under the condition of intensity modulation coefficient is 0.4. Besides that, Signal to Noise Ratio (SNR) also improves significantly.

Paper Details

Date Published: 9 November 2010
PDF: 6 pages
Proc. SPIE 7853, Advanced Sensor Systems and Applications IV, 785335 (9 November 2010); doi: 10.1117/12.870378
Show Author Affiliations
Qingping Shi, Tsinghua Univ. (China)
Liwei Wang, Tsinghua Univ. (China)
Huayong Zhang, Tsinghua Univ. (China)
Changdong Tian, Tsinghua Univ. (China)
Min Zhang, Tsinghua Univ. (China)
Qian Tian, Tsinghua Univ. (China)
Yanbiao Liao, Tsinghua Univ. (China)

Published in SPIE Proceedings Vol. 7853:
Advanced Sensor Systems and Applications IV
Brian Culshaw; Yanbiao Liao; Anbo Wang; Xiaoyi Bao; Xudong Fan; Lin Zhang, Editor(s)

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