近日，韩国中央大学的Kwang Yong Song及其研究小组与西班牙阿尔卡拉大学的Miguel Gonzalez-Herraez等人合作并取得一项新进展。经过不懈努力，他们基于双光频梳实现布里渊扩展时域分析。相关研究成果已于2024年7月2日在国际知名学术期刊《光：科学与应用》上发表。

本文介绍了布里渊扩展时域分析（BETDA）技术，该技术作为BOTDA系统的一种改进，能够同时实现高空间分辨率和低检测带宽。BETDA利用两个具有不同频率间隔的光频梳（OFCs）分别作为泵浦光和探头，通过捕捉它们在扩展时域内产生的谱拍轨迹来记录局部的布里渊增益谱。研究人员利用具有定制的频谱相位、线间距和带宽的双OFCs，在时域内成功测量了位于230米单模光纤中的2厘米长的热点，检测带宽小于100kHz。

据悉，布里渊光时域分析（BOTDA）作为一种广泛应用的分布式光纤传感技术，其核心在于通过脉冲调制泵浦波来局部检索布里渊增益或损耗谱的信息。BOTDA系统的空间分辨率本质上受限于脉冲的持续时间，这意味着要实现高分辨率的测量，就必须配备与分辨率成反比的高电子带宽。

附：英文原文

Title: Brillouin expanded time-domain analysis based on dual optical frequency combs

Author: Youn, Jae Hyeong, Song, Kwang Yong, Martin-Lopez, Sonia, Gonzalez-Herraez, Miguel, Fernnadez-Ruiz, Mara R.

Issue&Volume: 2024-07-02

Abstract: Brillouin Optical Time-Domain Analysis (BOTDA) is a widely-used distributed optical fiber sensing technology employing pulse-modulated pump waves for local information retrieval of the Brillouin gain or loss spectra. The spatial resolution of BOTDA systems is intrinsically linked to pulse duration, so high-resolution measurements demand high electronic bandwidths inversely proportional to the resolution. This paper introduces Brillouin Expanded Time-Domain Analysis (BETDA) as a modified BOTDA system, simultaneously achieving high spatial resolution and low detection bandwidth. Utilizing two optical frequency combs (OFCs) with different frequency intervals as pump and probe, local Brillouin gain spectra are recorded by their spectral beating traces in an expanded time domain. A 2-cm-long hotspot located in a 230m single-mode fiber is successfully measured in the time domain with a detection bandwidth of less than 100kHz using dual OFCs with tailored spectral phase, line spacing, and bandwidth.

DOI: 10.1038/s41377-024-01499-x

Source: https://www.nature.com/articles/s41377-024-01499-x