We report a high-spatial-resolution and long-range distributed temperature sensor through optimizing differential pulse-width pair Brillouin optical time-domain analysis (DPP-BOTDA). In DPP-BOTDA, the differential signal suffers from a signal-to-noise ratio (SNR) reduction with respect to the original signals, and for a fixed pulse-width difference the SNR reduction increases with the pulse width. Through reducing the pulse width to a transient regime (near to or less than the phonon lifetime) to decrease the SNR reduction after the differential process, the optimized 8/8.2 ns pulse pair is applied to realize a 2 cm spatial resolution, where a pulse generator with a 150 ps fall-time is used to ensure the effective resolution of DPP-BOTDA. In the experiment, a 2 cm spatial-resolution hot-spot detection with a 2 °C temperature accuracy is demonstrated over a 2 km sensing fiber.
© 2012 Optical Society of America
Remote Sensing and Sensors
Original Manuscript: September 7, 2011
Manuscript Accepted: December 7, 2011
Published: March 14, 2012
Yongkang Dong, Hongying Zhang, Liang Chen, and Xiaoyi Bao, "2 cm spatial-resolution and 2 km range Brillouin optical fiber sensor using a transient differential pulse pair," Appl. Opt. 51, 1229-1235 (2012)