Fiber Optic Distributed Acoustic Sensing (DAS) and Distributed Strain Sensing (DSS) systems have widespread use for
asset and security monitoring. The acoustic signal from such sources as intruders, vehicles, or gunfire must be coupled
from the earth to an optical fiber which is then interrogated by DAS system technology. Because the optical fiber is the
sensing element, and because the cable is required to mediate the interaction of the fiber and its environment, the
selection of the optical fiber, cable design, and deployment conditions are critical to the performance of the system.
Cable designs specifically created for sensing are shown to achieve 20 dB higher signal-to-noise than standard telecom
designs, which correspond to an enhanced sensing range of more than 30 meters. In addition, directly burying the
sensing cable in the ground leads to 15 dB higher sensitivity than installing it in a duct. In many cases, standard cables
for telecommunications applications are designed to isolate and protect the fibers from the external environment;
therefore a cable designed for sensing applications and deployed specifically with this in mind leads to the highest
sensitivity with the largest sensing range.