Distributed temperature and strain sensing with high order stimulated Brillouin scattering

Summary form only given. Stimulated Brillouin Scattering (SBS) has been extensively studied over the past few decades due to the many interesting properties and potential applications. Primarily, spontaneous Brillouin scattering (BS) has been used as a temperature and strain sensor enabling long range detection (tens of kilometres) with a relatively good spatial resolution (few meters) [1]. Such distributed temperature or strain sensors (DTSS) are capable of sensing 0.1°C temperature changes or micro-strains over long distances across large areas. However, sensitivity has remained mostly unchanged due to intrinsic properties of BS (1^st order Brillouin frequency shift) leading towards a typical sensitivity of respectively ~1.2 MHz/°C and ~0.046MHz/με to temperature and strain.In 2014, we proposed to improve the temperature sensitivity (6x) of a BS sensor by using higher order SBS [2]. In this paper, we show strain and temperature sensitivity increase of 6x and 10x respectively compared to commercially available DTSS devices. With this technique, we achieved ~12 MHz/°C, and ~0.28MHz/ με) as shown in Fig.1 b) and c). We also propose a new way of making this high sensitivity sensor truly distributed. Preliminary results of high order SBS generation within short period of time are shown in Fig.1 a).