Optical fiber vibration sensing system and using method thereof based on double Mach-Zehnder interferometers

Abstract

The invention discloses an optical fiber vibration sensing system and a using method thereof based on double Mach-Zehnder interferometers. An end A machine and a end B machine of the system are arranged at two ends of the interferometer, a control module of each end machine is connected with a light source as well as a detecting collection and communication module, the end A machine is further provided with a time synchronization module. A communication fiber is connected with the communication modules of the end A machine and the end B machine. The light source module of the end A machine and the end B machine is connected with the detecting collection module of an opposite end machine through a sensing optical fiber and an optical coupler to form double interferometers. The using method of the system comprises the following steps of: setting a threshold value by the control module of the end A machine, respectively outputting the interference information of optical signals of the end A machine and the end B machine to the opposite end machine; sending a collection triggering signal by the control module of the end A machine and starting to collect data by a second end machine when the sensing optical fiber influenced by vibrating to interfere in the information reaches the threshold value; determining the position of interfering on the sensing optical fiber by the control module of the end A machine according to two-path collecting data and the time synchronization information. The invention has double light sources, low loss of optical power, longer monitoring distance and higher sensitivity.

Description

(1) Technical field

[0001] The invention relates to optical fiber sensing technology, in particular to an optical fiber vibration sensing system based on a double Mach-Zehnder interferometer and a method for using it. (2) Background technology

[0002] In terms of long-distance security monitoring of pipelines, communication lines, and border lines, conventional sensing technologies such as infrared and cameras have encountered major technical bottlenecks. Due to the limited detection distance of a single sensing unit used in these methods, many sensing units need to be used to form a sensing network to increase the sensing distance, resulting in problems such as complex system structure and high construction and maintenance costs in long-distance detection.

[0003] Distributed optical fiber sensing technology can continuously measure the environmental parameters (including vibration, shock, temperature, etc.) distributed along the sensing optical fiber in real time. Compa...

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