布里渊光时域分析仪与马赫-曾德尔干涉仪共同检测传感技术

布里渊分布式光纤传感器适用于测量静态的温度/应力，而马赫-曾德尔干涉仪分布式光纤传感器(DOFS)可测量动态的应变变化。许多应用场合需要静态和动态的传感信息，这是单机理分布式光纤传感器难以达到的。由于布里渊光时域分析仪(BOTDA)和马赫-曾德尔干涉传感器都采用双向环路传感光纤结构，通过共用光源和主要光器件，将布里渊光时域分析仪和马赫-曾德尔干涉传感器相结合。利用布里渊传感测温度，马赫-曾德尔传感器测振动，从而可实现多机理多参量传感。搭建了25 km传感实验系统，对于马赫-曾德尔振动传感，定位精度达到60 m，并可计算振动频率；对于布里渊传感，在没有振动时传感光纤的始端和末端都为2 ℃的测量精度，但在振动时得到始端为3 ℃、末端为4 ℃的测量精度。

Distributed Optical-Fiber Sensor Combining Brillouin Optical Time Domain Analyzer with Mach-Zehnder Interferometer

Brillouin distributed optical fiber sensor is suitable for measuring the static temperature/strain, but Mach-Zenhder interferometer distributed optical fiber sensor (DOFS) can be used to measure the dynamic strain. Many practical applications need static and dynamic sensing information, which is beyond the capability of the single mechanism distributed optical fiber sensor. Considering optical-fiber sensors of Brillouin optical time domain analyzer (BOTDA) and optical-fiber sensors of Mach-Zenhder interferometer are both using the loop sensing fiber structures, BOTDA and Mach-Zenhder interference are combined together by sharing with the same sensing optical fiber, light source, and other optical devices. BOTDA is used to measure temperature, and Mach-Zenhder interferometer is applied to measure vibration. So, the sensor with multi-mechanism and multi-parameter can be achieved. A preliminary 25 km sensing experiment system is built for testing. For Mach-Zenhder′s vibration sensing, spatial accuracy can reach to 60 m, and the vibration frequency is able to be obtained. For BOTDA′s temperature testing, the beginning and end′s measurement accuracy are 2 ℃ without vibration in existence, and the accuracy becomes 3 ℃ and 4 ℃ respectively with vibration.