Distributed disturbance sensing device and the related demodulation method based on polarization sensitive optical frequency domain reflectometry

Patent metadata

Field	Value
Publication number	US-9322740-B2
Application number	US-201113880732-A
Country	US
Kind code	B2
Filing date	Dec 16, 2011
Priority date	Aug 18, 2011
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

This invention relates to a distributed disturbance sensing device based on polarization sensitive optical frequency domain reflectometry (OFDR) and the related demodulation thereof. The device, adopting OFDR, polarization controlling and analysis techniques, consists of a ultra-narrow linewidth tunable laser source module, polarization generating and polarization splitting balanced detecting module, laser source optical frequency and phase monitoring module, high-speed optical switch and so on to establish a large-scale and long-distance optical sensing network. The demodulation method consists of analysis the polarization information from sensing optical fiber, the method of suppressing and compensating of the non-linear optical frequency and the laser phase noise, super-resolution analyzing, advanced denoising method and the polarization information analysis method based on Jones and Mueller's matrices using distributed wave plate model of optical fiber.

First claim

What is claimed is:

1. A distributed disturbance sensing device based on polarization sensitive optical frequency domain reflectometry, comprising:
(a) a tunable laser source selected from the group consisting a tunable fiber laser and an external cavity semiconductor laser;
(b) a laser source driver connected to said tunable laser source;
(c) an optical splitter connected to said tunable laser source;
(d) an optical frequency and phase monitoring member, said optical frequency and phase monitoring member being selected from a group consisting of a depolarized Michelson interferometer and a Mach-Zehnder interferometer based on 3×3 coupler;
(e) a core interference member, being a core of an optical frequency domain reflectometer, which comprises a tunable polarization-maintaining attenuator, a polarization-maintaining splitter, a reference arm comprising a phase modulator and a 45° aligner, a test arm, and a polarization-maintaining coupler having two output ports;
(f) a polarization generating module, being part of said test arm of said core interference member and comprising a polarization state generator and a polarization-maintaining circulator;
(g) a polarization splitting balanced detecting member comprising two polarization splitters and two balanced detectors, said two polarization splitters being connected respectively to said two output ports of said polarization-maintaining coupler in said core interference member;
(h) a data acquisition member, said data acquisition member further connected to a computer; and
(i) an optical switcher.

2. The distributed disturbance sensing device according to claim 1 , wherein said optical frequency and phase monitoring member is a depolarized Michelson interferometer structure, which comprises an isolator, a coupler with a splitting ratio of 50:50, two Faraday rotating mirrors, a photo detector, an optical delay fiber and a phase modulator.

3. The distributed disturbance sensing device according to claim 1 , wherein said optical frequency and phase monitoring member is a Mach-Zehnder interferometer structure based on a 3×3 coupler, which comprises a splitter with a splitting ratio of 50:50, an optical delay fiber, a 3×3coupler and two detectors.

4. A demodulation method for a distributed disturbance sensing device based on polarization sensitive optical frequency domain reflectometry, comprising the following steps:
(1) collecting optical phase or optical frequency of a laser from a tunable laser source to obtain optical frequency or phase information of the laser at a plurality of time intervals;
(2) based on the information of optical frequency and phase collected in step (1), compensating two orthogonal polarization signals from a core interference member in order to reduce an influence of nonlinearity of optical frequency and phase noises of the laser on signal-to-noise ratio and spatial resolution;
(3) performing spectral analysis on the compensated signals of the core interference member by non-parametric or parametric spectral estimation;
(4) denoising the signals processed in step(3), using one or more procedures selected from the group consisting of wavelet denoising, Wiener deconvolution adaptive denoising, median denoising, morphology denoising, partial differential denoising, and denoising based on local statistical features; and
(5) performing polarization calculation on the signals processed at step (4) based on optical fibers equivalent to a multiple wave plates concatenation model.

Assignees

• Liu Tiegen
• Liu Kun
• Ding Zhenyang
• Jiang Junfeng
• Li Dingjie
• Univ Tianjin

Inventors

• Liu Tiegen
• Liu Kun
• Ding Zhenyang
• Jiang Junfeng
• Li Dingjie

Classifications

• G01H9/004

  using fibre optic sensors (light guides per se G02B6/00, acousto-optical devices specially adapted for gating or modulating in optical wave guides G02F1/125) · CPC title

• G01M11/3172 Primary

  Reflectometers detecting the back-scattered light in the frequency-domain, e.g. OFDR, FMCW, heterodyne detection · CPC title

• G01M11/3181

  Reflectometers dealing with polarisation · CPC title

• G01D5/35325

  using interferometer with two arms in reflection, e.g. Mickelson interferometer · CPC title

• G01D5/35329 Primary

  using interferometer with two arms in transmission, e.g. Mach-Zender interferometer · CPC title