Self-heterodyne detection for SNR improvement and distributed phase-shift measurements in BOTDA

Abstract

In this paper we present a Brillouin optical time domain analysis (BOTDA) sensor that takes advantage of the enhanced characteristics obtained employing self heterodyne optical detection combined with synchronous demodulation. By employing this technique we increase the sensitivity of the sensor and demonstrate experimentally a 12.35 dB enhancement in the SNR compared to conventional direct-detection systems. This detection scheme also enables distributed measurements of the Brillouin phase shift in an optical fiber, which can lead to enhanced BOTDA schemes.