Method of utilizing a fiber for simultaneously measuring distributed strain and temperature

Abstract

A method that utilizes a dispersion-shifted fiber having compound compositions with different temperature coefficients in core to simultaneously measure the distributed strain and temperature based on Brillouin frequency shift is disclosed. The present method includes the steps of obtaining mean two peak frequencies in a multi-peak Brillouin spectrum of the dispersion-shifted fiber, determining a temperature change according to the formula of a Brillouin frequency shift of the peak relating to strain and temperature conditions of the fiber, and determining a strain change through the formula. In a 3682-m sensing length of Large-Effective-Area NZ-DS fiber, a temperature resolution of 5.degree. C., a strain resolution of 60 .mu..epsilon. and a spatial resolution of 2 m are achieve simultaneously.