Phase Sensitive Optical Time Domain Reflectometer and Its Realization Method Based on Golay Complementary Sequence

An optical time domain reflectometer, complementary sequence technology, applied in instruments, using wave/particle radiation, measuring devices, etc., can solve problems such as inter-symbol crosstalk, and achieve the goal of improving average power, extending sensing distance, and ensuring response speed. Effect

Active Publication Date: 2019-06-25
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Problems solved by technology

Since the phase encoding cannot realize the return-to-zero code, there will be a problem of intersymbol crosstalk

Method used

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  • Phase Sensitive Optical Time Domain Reflectometer and Its Realization Method Based on Golay Complementary Sequence
  • Phase Sensitive Optical Time Domain Reflectometer and Its Realization Method Based on Golay Complementary Sequence
  • Phase Sensitive Optical Time Domain Reflectometer and Its Realization Method Based on Golay Complementary Sequence

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Embodiment Construction

[0041] The present invention will be further described below in conjunction with the accompanying drawings. Embodiments of the present invention include, but are not limited to, the following examples.

[0042] Firstly, it is explained that the phase-sensitive optical time domain reflectometer (Φ-OTDR) for phase demodulation is a linear system. The linear system is the basis and premise for the implementation of coding. Let the codeword repetition period (bit rate) be the same as the sampling time interval (sampling rate); let the φ-OTDR system response of a pulse with an amplitude of 1 and an initial phase of 0 be r(t); let the length be S+1 An arbitrary coding sequence for Assuming that the total number of points sampled on the fiber is H+1, the response of the single-pulse system is r(t)=[r 0 exp(jρ 0 ),...,r H exp(jρ H )] T . figure 1 The response of the system when S=2, H=1 is briefly described. figure 1 The codeword in is [1, 1, 1] T , the curves labeled ①, ②,...

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Abstract

The invention relates to a phase-sensitive optical time-domain reflectometer based on a Golay complementary sequence. The reflectometer comprises an input light generating unit (1), a polarization-maintaining beam splitter (2), a coding sequence modulating unit (3), and a circulator (4), optical fiber to be tested (5), homodyne frequency shifter (6), polarization control unit (7), detection unit (8) and signal demodulation unit (9); also discloses the realization based on Golay complementary sequence simultaneously Phase Sensitive Optical Time Domain Reflectometer Method. The detection unit of the present invention uses an I / Q demodulation system, which can effectively restore all the light field information, especially the absolute phase information, of the real backward Rayleigh scattered light in real time with a refined structure; its local oscillator light gain makes it possible to demodulate the fiber tail The extremely weak signal at the end becomes possible, so this system helps to extend the sensing distance of the system.

Description

technical field [0001] The invention relates to a phase-sensitive optical time-domain reflectometer, which belongs to the field of optical fiber measurement and sensing. More specifically, the invention relates to a new phase-sensitive optical time-domain reflectometer based on Golay complementary sequence, and a new phase-sensitive optical time-domain reflectometer based on Golay complementary sequence. Sequential implementation of a phase-sensitive optical time-domain reflectometer method. Background technique [0002] Distributed Fiber Optic Sensing (DFOS) is widely used in modern society, especially in the fields of oil transmission, power monitoring, large structure security and border security. The basic principle of distributed optical fiber sensing is that changes in external environmental factors, such as temperature, vibration, etc., lead to changes in the characteristics of the optical fiber itself, such as the refractive index, which in turn affects the transmiss...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01H9/00
CPCG01H9/004
Inventor 王子南傅芸张滨饶云江
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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