Brillouin distributed temperature sensor employing phase modulation and optimization techniques

The process of signal-to-noise ratio (SNR) improvement and the suppression of stimulated Brillouin scattering (SBS) effects on a long-range distributed sensor are presented in this paper. We have proposed an improved performance Brillouin distributed temperature sensor using phase modulation and optimization techniques. Global evolutionary computing-based optimization techniques (genetic algorithm (GA), particle swarm optimization (PSO) and differential evolution algorithm (DE)) are applied for both fiber and receiver optimization. The combination of phase modulation and the global evolutionary computing technique improved the SBS threshold power of the proposed system to an extent of 5.95 dBm. However, with receiver and fiber optimization, for an input power of 0 dBm, the proposed system provides SNR improvement up to 3.5 dB, for temperature sensing over a distance of 50 km with temperature resolution of 1.44 K and spatial resolution of 32 m without using filter. However, for the equivalent sensing range, we have achieved a temperature resolution as 0.51 K using the above optimized system with filter.