Performance improvement method of single-ended BOTDA system based on Fresnel reflection

摘要

To solve the problems of small signal intensity and low signal-to-noise ratio (SNR) in single-ended Brillouin optical time domain analysis (BOTDA) system based on Fresnel reflection, we propose and experimentally demonstrate a pulse coding single-ended BOTDA system, which can improve the SNR and temperature measurement accuracy. A single-ended BOTDA temperature sensing system using single pulse and pulse coding is designed, and the Brillouin time domain signal and Brillouin frequency shift under different pulse coding bits are measured. The experimental results show that the fluctuations of Brillouin power and Brillouin frequency shift are gradually decreased with the increase of pulse coding bits, and the SNR under 32 bit Golay coding offers a 6.18 dB improvement with respect to traditional single pulse system. And the temperature measurement accuracy under 32 bit coding over a 9.35-km-long sensing fiber can be accurately measured as 1.59 degrees C, while providing a 1.73 degrees C enhancement when compared to single pulse system.