150 km long distributed temperature sensor using phase modulated probe wave and optimization technique

This paper describes and demonstrates the performance enhancement of a 150 km distributed sensing system based on Brillouin optical time-domain analysis (BOTDA). We present a BOTDA system combining the phase modulation and global evolutionary computing based optimization technique (Differential Evolution algorithm (DE)) for receiver optimization. We achieved an SNR improvement of 3.3 dBm compared to amplitude modulated probe wave for 150 km sensing range. We successfully demonstrate the presence of hot spot at a distance of 51 km of the sensing fibre for different temperatures.