Phase BOTDR based Distributed Acoustic Sensing

Abstract

In this research, a novel phase-BOTDR based distributed acoustic sensing method using the phase change occurring along the sensing fiber due to the ambient temperature has been proposed. In this method, distributed phase change information has been obtained depending on temperature variation on the model built up for making analysis and performing corresponding simulations. Moreover, the differential analysis of the product of fiber core refractive index and quantity change of fiber length has been attained and the linear equations related to the temperature and core refractive index dependencies of phase change have been derived. Furthermore, the temperature dependence of phase change has been obtained as 45.667 rad/°K. For the variations of core refractive index in 1.44183-1.44188 range, values of phase change have been acquired in the range of 0 rad - 227.7 rad. In other words, a 1 rad increasing in phase change induces the variation in value of ~ 2.23×10-7 on the core refractive index of the sensing fiber.