High-repetition-rate distributed Brillouin sensor by correlation domain analysis with differential frequency modulation

Abstract

A novel kind of high repetition-rate distributed Brillouin sensor is proposed and experimentally demonstrated based on optical correlation-domain analysis with differential frequency modulation, where the optical frequencies of the pump and the probe waves are modulated at slightly different RF frequencies so that the temporal position of the measurement is continuously and repeatedly swept along a fiber under test. A distribution map of Brillouin frequency variation along a 100 m optical fiber is acquired at a repetition rate of 20 Hz with an accuracy of +/- 2.5 MHz and a spatial resolution of about 80 cm.