新型微结构光纤分布式声波传感技术及应用

New Type of Microstructure-Fiber Distributed Acoustic Sensing Technology and Its Applications

介绍了一种新型分布式微结构光纤及微结构光纤分布式声波传感技术.通过在普通通信光纤的纤芯采用精密光刻技术连续制备纵向微结构散射单元,形成一种新型分布式微结构光纤(distributed microstructure optical fiber,DMOF).基于这种DMOF研制的微结构光纤分布式声波传感系统(microstructure fiber distributed acoustic sensor,MF-DAS),采用微结构光散射增强,MF-DAS传感信号的信噪比得到大幅提升;通过微结构光纤链路均衡,大幅度降低MF-DAS近远端传感信号差值;提出微结构光时域反射(microstructure optical time domain reflection,M-OTDR)时隙分插复用扩频,显著增大了分布式声波探测频响带宽.这种新型的MF-DAS系统具备高灵敏、大尺度、宽频响等优越性能,在地下及水下声波信息获取、重大基础设施内部损伤探测与外部侵害安全监测等领域具有十分广阔的应用前景.

A new distributed microstructure optical fiber(DMOF)and a distributed acoustic sensing technology based on the DMOF are introduced in this paper.The DMOF is a new type of longitudinal microstructure fiber formed by continuously preparing microstructure scattering unit in the core of ordinary communication optical fiber through precise lithography technology.The microstructure-fiber distributed acoustic sensor(MFDAS)based on this new type of DMOF has superior performance such as high sensitivity,large monitoring scale and wide frequency response.The key technologies and research progress of the MF-DAS are introduced in this paper,including that the signal-to-noise ratio of the MF-DAS sensing signal is increased by enhancing the microstructure light scattering,the near-far-end signal difference of the MF-DAS is reduced by the microstructure fiber link equalization,and the response broadband of detectable distributed sound-wave is improved significantly by the microstructure optical time domain reflection(M-OTDR)and the time slot multiplexing of microstructure optical time domain reflection.The new MF-DAS features with large-scale,high-sensitivity and broad response bandwidth in the acquisition of sound wave information,and shows a very broad application prospect in the injury detection of critical infrastructure and the security monitoring of external intrusion.