Analog Signal Processing in Cost-Effective Raman OTDR Distributed Temperature Sensing System

A novel approach to the development of Distributed Temperature Sensing (DTS) systems based on Raman Scattering in Multimode optical fibers operating at around 800nm is presented, focusing on applications requiring temperature profile measurement in the range of few hundred meters. Differently from the standard Raman DTS systems which aims to shorten as more as possible the pulse space width for improving the precision of measurement, the novel approach studied in this work is based on the use of pulses with a space width which equals approximately the distance covered by the fiber under test. The proposed technique relies on analog processing for obtaining the temperature profile measurement. This solution simplifies the electronic circuit development, minimizing Signal to Noise Ratio (SNR) and post processing timing.