Qi Yifei, Lin Shengtao, Zhang Jiaojiao, Wang Pan, Wang Zinan
Opt Express. 2022 Jun 6;30(12):21268-21275. doi: 10.1364/OE.458698.
In the ultra-long distance sensing domain, recently Raman random fiber laser (RRFL) demonstrated advantages of ultrawide sensing-bandwidth in dynamic sensing, compared with pulse-probing cases. However, such a scheme is still in the preliminary stage, and the key parameters such as sensitivity have not been characterized. In this work, a time-dependent spectrum-balanced model is proposed, which can accurately and quickly describe the spectral shape of RRFL and the evolution of the power and the spectrum. Based on this model, the relationship between the sensitivity and the feedback bandwidth is studied. The calculated results show that the sensitivity is inversely proportional to the feedback bandwidth. Then in the proof-of-concept experiment, by changing the bandwidth of sensing FBG, the results of sensitivity are well coincident with the simulation. This work provides an effective platform for studying the evolution of RRFL spectrum, as well as a novel way for further enhancing the performance of the dynamic sensing system based on ultra-long RRFL.
在超长距离传感领域，最近拉曼随机光纤激光器（RRFL）与脉冲探测情况相比，在动态传感中展现出超宽传感带宽的优势。然而，这种方案仍处于初步阶段，诸如灵敏度等关键参数尚未得到表征。在这项工作中，提出了一种随时间变化的光谱平衡模型，该模型能够准确且快速地描述RRFL的光谱形状以及功率和光谱的演变。基于此模型，研究了灵敏度与反馈带宽之间的关系。计算结果表明，灵敏度与反馈带宽成反比。然后在概念验证实验中，通过改变传感光纤布拉格光栅（FBG）的带宽，灵敏度结果与模拟结果吻合良好。这项工作为研究RRFL光谱的演变提供了一个有效的平台，同时也为进一步提升基于超长RRFL的动态传感系统的性能提供了一种新方法。
