• ISSN 2097-1893
  • CN 10-1855/P

光纤振动传感之二:基于散射或透射光的本征传感及其地震学应用

Fiber-optic vibration sensing ‒ II: Intrinsic sensing with scattered or transmitted light and their seismological applications

  • 摘要: 本征光纤振动传感通过在光纤一端重复发射探测激光,在光纤同端或另外一端接收散射光或透射光并解调它们的变化,测量光纤上的动态应变(即振动). 本征传感以光纤为传感器,具有结构简单,布设灵活,运维方便的优点,能应用于流体、高温、高压或强电磁干扰等恶劣环境,可以大幅度延伸可监测的区域,并实现相对廉价的长期连续监测. 此外,光纤传感还可以利用全球城市内、城际间和跨洋等已有光缆中的冗余光纤资源,快速构建振动监测网络,改善振动监测能力. 目前基于散射光的振动传感,单台仪器可以实现沿光纤米级间隔、近百千米的密集分布式监测;而基于透射光的传感,尚缺乏分布式观测能力,但可检测上万千米长光纤上的强烈振动. 本文介绍这两类本征光纤振动传感相关的基本原理、应用实例和发展前景.

     

    Abstract: The intrinsic vibration sensing of optical fiber measures the dynamic strain (i.e., vibration) along with the fiber by repeatedly emitting detection lasers at one end of the fiber, receiving scattered or transmitted light at the same or another end, and demodulating its changes. The sensing system takes the fiber as sensors and has the advantages of being flexible and straightforward to build, and being easy to operate and maintain. It can be used in harsh environments with fluid, high temperature, high pressure, or strong electromagnetic interference. As a result, it can significantly expand the monitorable area while also achieving relatively low-cost and long-term continuous monitoring. Furthermore, many redundant fiber resources already present in fiber optic cables of cities, intercity, and across oceans around the world. Utilizing these fiber optic resources can be quickly converted to vibration monitoring networks, significantly improving vibration monitoring capabilities in these areas.Today, a single instrument can achieve intensive distributed monitoring along with the nearly 100 kilometers fiber with meter-level intervals based on vibration sensing of scattered light. At the same time, sensing based on transmission light lacks distributed observation capability but can detect strong vibration along optical fibers tens of thousands of kilometers long. This paper describes the fundamental principles, application scenarios and prospects of these two types of fiber-optic vibration sensing.

     

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