Vector optical-chirp-chain Brillouin optical time-domain analyzer based on complex principal component analysis

Abstract

A vector optical-chirp-chain (OCC) Brillouin optical time-domain analyzer (BOTDA) based on complex principal component analysis (CPCA) is proposed and experimentally demonstrated by employing a tour-tone OCC probe with two orthogonal polarization states. The polarization-fading-free complex Brillouin spectrum (CBS) of the vector OCC-BOTDA is obtained by combining the amplitude and phase response spectra of the probe wave at both Brillouin gain and loss region. We utilize the CPCA method to determine the Brillouin frequency shift (BFS) directly using the measured CBS, and the sensing accuracy is improved by a factor of up to 1.4. The distributed temperature sensing is demonstrated over a 20 km standard single-mode fiber with a 6 m spatial resolution and less than 1 MHz frequency uncertainty under 10 times of trace averaging. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement