Ultrahigh resolution distributed temperature and strain sensing in optical fibre with Rayleigh and Brillouin scattering

Distributed temperature and strain sensing (DTSS) using optical fibre has many applications in monitoring the security and stability of infrastructure. Early detection is important to avoid catastrophic faults from occurring. This requires enhanced sensitivity of sensors, much beyond what is available today. Our work has centred on the enhancement of temperature and strain sensing using stimulated Brillouin scattering for the first time, which we recently demonstrated. In this scheme, the sensitivity of the sensor is given by order of the stimulated Stokes wave used for the sensor, and the sensing technique uses an identical SBS oscillator with the same seed source for common mode rejection, simplifying of the detection scheme. In addition we have also recently enhanced the capability for distributed sensing using Rayleigh scatter in a novel scheme. The latter technique has very high spatial resolution over limited distance, ideal for buildings and local infrastructure monitoring.