Millimeter-level recognition capability of BOTDA based on a transient pump pulse and algorithm enhancement
Dengwang Zhou, Dexin Ba, Benzhang Wang, Liqiang Qiu, Wuliji Hasi, Yongkang Dong
Abstract
Brillouin optical time-domain analysis requires a pulsed pump to obtain a distributed Brillouin gain spectrum (BGS) containing environmental information, whose width corresponds to spatial resolution (SR). We propose a rising edge demodulation (RED) algorithm acting on Brillouin information generated by a transient pump pulse ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo><</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">p</mml:mi> <mml:mi mathvariant="normal">h</mml:mi> <mml:mi mathvariant="normal">o</mml:mi> <mml:mi mathvariant="normal">n</mml:mi> <mml:mi mathvariant="normal">o</mml:mi> <mml:mi mathvariant="normal">n</mml:mi> </mml:mrow> </mml:math> lifetime) via a nonlinear weight matrix to enhance SR. The distributed BGS generated by using an 8-ns transient pump pulse is processed by the RED algorithm, and its SR is enhanced from 0.8 m to 1 mm (i.e., 800-fold improvement) in the simulation and 8 mm (i.e., 100-fold improvement) in the experiment.