Distributed Fiber Optic Sensing for Homeland Security

The need to protect our borders and critical infrastructure, such as pipelines, power distribution, and transportation, has grown in importance over the last few years. To address this need, fiber optic sensing technology developed in the Optical Sciences Division at NRL for antisubmarine warfare applications has recently been adapted to homeland security applications. Ground-based seismic sensing applications have significantly different requirements than traditional underwater acoustic applications. As a result, new optical interrogation and signal processing techniques are needed. Border and critical infrastructure sensor systems must be able to monitor long lengths several km to several 10s of km with reasonable spatial resolution 5 to 100 m, and have sufficient seismic sensitivity to detect targets of interest. We have developed and recently field-tested a fiber optic distributed seismic sensor system capable of meeting these requirements and report on some initial observations below.