We present a model and numerical simulation of a distributed temperature sensor based on a two-pulse differential coherent optical time-domain reflectometer (COTDR). The differential phase measured using a phase-sensitive Rayleigh reflectometer is shown to have a regular component, which is a linear function of temperature, and a random component, which is related to a random distribution of scattering centres in the fibre and restricts the accuracy of measurements of variations in temperature. Measurement accuracy can be improved by reducing the relative contribution of the random component via a decrease in pulse duration and/or an increase in the time delay between pulses. The spatial resolution of a differential two-pulse phase-sensitive reflectometer is shown to be determined by the time delay between pulses and to vary little with pulse duration. At a typical pulse duration (200 ns) and delay time (300 ns), the accuracy in measurements of variations in temperature in the 0.1-...

中文翻译：

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基于二脉冲差分相干反射仪的分布式温度传感器的测量精度和空间分辨率

我们提出了一种基于双脉冲差分相干光学时域反射仪（COTDR）的分布式温度传感器的模型和数值模拟。使用相敏瑞利反射仪测得的差分相位具有正则分量（随温度变化的线性函数）和随机分量（与光纤中散射中心的随机分布有关），并限制了精度。测量温度变化。通过减少脉冲持续时间和/或增加脉冲之间的时间延迟来减少随机分量的相对影响，可以提高测量精度。差分二脉冲相敏反射计的空间分辨率显示为由脉冲之间的时间延迟确定，并且随脉冲持续时间变化很小。在典型的脉冲持续时间（200 ns）和延迟时间（300 ns）下，温度变化的测量精度为0.1 -...