基于布里渊增益-损耗谱的高精度分布式传感器

A Highly Accurate Distributed Sensor Based on the Brillouin Gain-Loss Spectrum

提出一种基于布里渊增益和损耗相互作用的光时域分析系统,该系统将连续光与反向的斯托克斯和反斯托克斯脉冲同时输入光纤,通过声光相互作用在布里渊增益谱中心频率处产生一个窄线宽的吸收峰。该吸收峰的线宽约为布里渊增益谱宽的1/5,并且其频率与布里渊频移相关。因此利用该窄线宽吸收峰可以提高布里渊传感器的频率分辨率,从而实现高精度的温度和应变测量。实验结果表明,与传统的基于布里渊增益谱的传感器相比,该方案的温度测量精度提高了1倍多。

An optical time domain analysis system that is based on the interaction between the Brillouin gain and loss is proposed. A continuous wave propagates with reverse pulses at its Stokes and anti-Stokes frequencies in an optical fiber. Further, a narrow linewidth absorption peak is observed at the center frequency of the Brillouin gain spectrum. The linewidth of the absorption peak is approximately 1/5 of that observed in the Brillouin gain spectrum, and the frequency of the absorption peak is related to the Brillouin frequency shift. Therefore, the frequency resolution of a Brillouin sensor can be improved by the narrow linewidth absorption peak; thus, highly accurate temperature or strain measurements can be achieved. The experimental result depicts that the accuracy of the temperature measured by this scheme is more than doubled, compared with the traditional Brillouin gain spectrum based sensor.