Multi-light source phase sensitive light time domain reflectometer and method thereof

Abstract

The invention discloses a multi-light source phase sensitive light time domain reflectometer and a method thereof. The reflectometer includes a plurality of lasers, multiple first couplers, multiple second couplers and multiple photodetectors. Continuous light emitted from the different lasers are different in wavelengths. The continuous light emitted from the lasers is shunted through the first couplers to the second couplers and a wavelength division multiplexing modulation module. The wavelength division multiplexing modulation module modulates the multi-channel continuous light into pulsedlight, combines the pulsed light into one channel light, outputs the one channel light to a fiber amplifier, and then outputs the amplified light to a three-port circulator. A second wavelength division multiplexer inputs backward Rayleigh scattering light of different wavelengths to the second couplers with the same wavelength continuous light for interference. The photodetectors convert the multi-channel interference light signals into electric signals and transmit the signals to a data collector and a control analysis module to obtain sensing information of a fiber. Through adoption of theplurality of lasers different in wavelength and the plurality of photodetectors, the anti-polarization fading characteristics of the system are improved.

Description

technical field [0001] The invention relates to the technical field of distributed optical fiber vibration sensors, and more specifically relates to a multi-light source phase-sensitive optical time-domain reflectometer and a method thereof. Background technique [0002] The optical time domain reflectometer (OTDR) uses the Rayleigh scattered light generated when the pulsed light propagates in the optical fiber to obtain attenuation information, which is an indispensable tool for optical cable construction and monitoring. However, because the traditional OTDR uses a low-coherence broadband light source, it can only detect changes in light intensity information in Rayleigh scattered light, so it can only realize functions such as fiber length, fiber attenuation, and fiber fault location. In 1993, H.F.Taylor et al proposed the phase-sensitive optical time-domain reflectometry (φ-OTDR). The change of the light intensity information in the scattered light can be used, and the c...

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Problems solved by technology

[0010] An object of the present invention is to provide a multi-light source phase-sensitive optical time-domain reflectometer and its method, which overcomes the adverse effects of interference fading on detection, enhances the anti-polarization fading characteristics of the system, and solves the problem of phase-sensitive optical time-domain reflection The Problem of Polarization Fading in Meters

[0011] Another object of the present invention is to provide a multi-light source phase-sensitive optical time-domain reflectometer and its method. By controlling the triggering moment of the optical signal modulator and increasing the number of measurements of the same point in space, the phase-sensitive optical time-domain reflectometer is improved. The frequency response range of the reflectometer solves the problem of low frequency response of the phase-sensitive optical time domain reflectometer

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