Coherent OTDR for Measuring Distributed Temperature and Strain with High Resolution in km-long Fiber

We researched a typical coherent optical time domain reflectometry system in which Rayleigh backscattering in a single-mode optical fiber was measured by coherent OTDR employing with a precisely frequency-controlled light source. The system can measure distributed temperature and strain with a resolution of 0.01 ℃ and a spatial resolution of 1 m in km-long fiber. Our simulation confirmed that the COTDR system enables us to measure distributed temperature and strain with high resolution. Backscattered power from the sensing fiber was measured and processed in simulation. This temperature resolution is two orders of magnitude better than that provided by the conventional BOTDR system.