Pastor-Graells J, Martins H F, Garcia-Ruiz A, Martin-Lopez S, Gonzalez-Herraez M
Opt Express. 2016 Jun 13;24(12):13121-33. doi: 10.1364/OE.24.013121.
So far, the optical pulses used in phase-sensitive OTDR (ΦOTDR) were typically engineered so as to have a constant phase along the pulse. In this work, it is demonstrated that by acting on the phase profile of the optical pulses, it is possible to introduce important conceptual and practical changes to the traditional ΦOTDR operation, thus opening a door for new possibilities which are yet to be explored. Using a ΦOTDR with linearly chirped pulses and direct detection, the distributed measurement of temperature/strain changes from trace to trace, with 1mK/4nε resolution, is theoreticaly and experimentaly demonstrated. The measurand resolution and sensitivity can be tuned by acting on the pulse chirp profile. The technique does not require a frequency sweep, thus greatly decreasing the measurement time and complexity of the system, while maintaining the potential for metric spatial resolutions over tens of kilometers as in conventional ΦOTDR. The technique allows for measurements at kHz rates, while maintaining reliability over several hours.
到目前为止，用于相敏光时域反射仪（ΦOTDR）的光脉冲通常被设计为沿脉冲具有恒定相位。在这项工作中，证明了通过作用于光脉冲的相位分布，可以对传统的ΦOTDR操作引入重要的概念和实际变化，从而为尚未探索的新可能性打开一扇门。使用具有线性啁啾脉冲和直接检测的ΦOTDR，理论和实验证明了温度/应变变化从迹线到迹线的分布式测量，分辨率为1mK/4nε。通过作用于脉冲啁啾分布可以调整被测量的分辨率和灵敏度。该技术不需要频率扫描，从而大大减少了测量时间和系统复杂性，同时保持了与传统ΦOTDR一样在数十公里范围内实现米级空间分辨率的潜力。该技术允许以kHz速率进行测量，同时在数小时内保持可靠性。
