A new demodulation method for time division multiplexing system of fiber-optic hydrophone using a 3×3 coupler

被引：6

作者：

Zhang H. ^{[1
]}

Wang L. ^{[1
]}

Shi Q. ^{[1
]}

Tian C. ^{[1
]}

Zhang M. ^{[1
]}

Liao Y. ^{[1
]}

机构：

[1] Optical Fiber Sensor Laboratory, Department of Electronic Engineering, Tsinghua University

来源：

Zhongguo Jiguang/Chinese Journal of Lasers | 2011年 / 38卷 / 05期

关键词：

3×3; coupler; Estimation of parameters; Fiber optics; Fiber-optic hydrophone; Path-matched differential interferometer; Signal demodulation; Time division multiplexing;

D O I：

10.3788/CJL201138.0505011

中图分类号：

学科分类号：

摘要：

A new demodulation method is proposed for time division multiplexing system of fiber-optic hydrophone using a 3×3 coupler. In such a scheme, the fiber-optic hydrophone is made by a 2×2 coupler and 3×3 coupler is used as path-matched differential interferometer. The signal is demodulated by linear combination of the three outputs and digital inverse arctangent approach. Parameters used in demodulation are estimated by singular-value decomposition and ellipse fitting. There is no carrier in this demodulation scheme. In addition, fiber-optic hydrophone can form a nearly zero path difference interferometer which is good for reducing system phase noise. The demodulation method is very simple and feasible for a general asymmetric 3×3 coupler. Correspondingly, it is easy to get a large dynamic range for the demodulated signal. A time division multiplexing experiment system with two sensors is set up. At 1 kHz noise floor, dynamic range, and cross talk are less than 31 μrad/√Hz, more than 125 dB, less than 64 dB, respectively.

引用

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