Approach for faster signal processing in ϕ-OTDR systems based on the directional measurement of fiber slice interaction

Abstract

Recently, fully distributed fiber sensors such as C-OTDR and ϕ-OTDR systems have drawn considerable attention from researchers. These sensors are ideal for industrial use because of their wide dynamic range, good spatial resolution, and high accuracy. However, for distributed acoustic sensors (DAS), the agility of sensor response, processing time, and data stacking have been significant challenges. These limitations are exacerbated in seismology applications for which we must record data for several hours or even several days. In this study, based on the interaction between scattering disks in a sensing fiber, we presented a new signal processing approach for heterodyne DAS systems. This approach can lead us to a direct measurement without the requirement of using or creating bulky functions in our computer interface. These measurements are easy to implement either in machine-level or high-level programming languages. We demonstrated that the speed of a DAS system can be increased while system parameters suffer only minor or no degradation. This processing idea provided us with a signal-to-noise ratio that was 1.5 dB higher than a conventional method; moreover, it increased the speed by ∼40%.