Distributed Sensing System Based on Michelson-Sagnac Fiber Interferometer

A fiber optic interferometer and sensing system technology, which is applied in the use of optical devices to transmit sensing components, convert sensor outputs, instruments and other directions, can solve problems such as inability to locate, and achieve solutions to inability to locate, improve sensitivity and positioning accuracy, and expand frequency. Effect of Response Range

Active Publication Date: 2021-10-26
FUDAN UNIV
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Problems solved by technology

The invention can improve the long-distance distributed optical fiber sensing sensitivity and positioning accuracy, expand the frequency response range of the distributed optical fiber sensing system, and solve the problem that the traditional solution cannot be positioned when it is applied to the positioning of buried optical cables

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  • Distributed Sensing System Based on Michelson-Sagnac Fiber Interferometer
  • Distributed Sensing System Based on Michelson-Sagnac Fiber Interferometer
  • Distributed Sensing System Based on Michelson-Sagnac Fiber Interferometer

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Embodiment Construction

[0054] The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0055] The present invention is based on Michelson-Sagnac optical fiber interferometer distributed sensing system such as figure 1 As shown, the narrow-band laser used in the system is a distributed feedback laser (DFB) with a center wavelength of 1550.12nm, and the broadband light source is a superluminescent light-emitting diode (SLD). light source. After the laser light enters the 3×3 fiber coupler, it will be divided into three beams of equal power, one of which will be coupled out of the core when passing through the knotted fiber. An optical isolator eliminates optical reflections, and four photodetectors PD1, PD2, PD3, and PD4 are used for photoelectric conversion. Between wavelength division multiplexer 2 (WDM2) and wavelength division multiplexer 3 (WDM3), there is a time delay fiber (TDF), which is located in the center of the ce...

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Abstract

The invention belongs to the technical field of optical fiber sensing, in particular to a distributed sensing system based on a Michelson-Sagnac optical fiber interferometer. The system of the present invention uses the two arms of the Michelson fiber optic interferometer as the sensing arms, and the two sensing arms are distinguished by a signal analysis algorithm; the two interferometers detect the same time-varying disturbance at the same time, and perform addition and subtraction processing on the demodulated phases , two signals with time delay are obtained, and the time delay related to the disturbance position is obtained by cross-correlation, and the disturbance position information can be calculated. The maximum detection distance of the system can reach 140km, and there is no blind spot. The system of the present invention utilizes the Michelson-Sagnac hybrid optical fiber interferometer to realize distributed optical fiber sensing and positioning, improve long-distance distributed sensing sensitivity and positioning accuracy, expand the frequency response range of the distributed optical fiber sensing system, and solve the problem of traditional solutions applied to The difficulty of positioning when locating buried optical cables.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, in particular to a distributed sensing system based on a Michelson-Sagnac optical fiber interferometer. Background technique [0002] Distributed fiber optic sensors are often used in perimeter security, oil pipeline leakage monitoring, power cable damage monitoring, bridge safety monitoring and other fields. The optical fiber integrates sensing and transmission, and can carry out continuous vibration or temperature measurement on the entire length of the optical fiber, and at the same time obtain the specific position of the measured object. The distributed optical fiber sensing system based on Michelson optical fiber interferometer has the characteristics of two-arm sensing and high sensitivity to low frequency signals. However, in the distributed sensing and positioning applications using this structure, no matter it is based on time delay estimation or notch point algorithm, it...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01D5/353
CPCG01D5/35322G01D5/35325
Inventor 贾波宋秋衡吴红艳
Owner FUDAN UNIV
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