Method for Improving Spatial Resolution and Amplitude by Optimized Deskew Filter in Long-Range OFDR
Method for Improving Spatial Resolution and Amplitude by Optimized Deskew Filter in Long-Range OFDR
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DOI：
10.1109/jphot.2014.2352622
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发表时间：
2014-10-01
影响因子：
2.4
通讯作者：
Jiang, Junfeng
中科院分区：
文献类型：
--
作者：
Du, Yang;Liu, Tiegen;Jiang, Junfeng
提出了一种通过优化去扭斜滤波器来提高远程光频域反射测量（OFDR）的空间分辨率和幅度的方法。在先前的抗扭斜滤波器方法中，由于从辅助干涉仪估计的非线性相位被用于补偿从主OFDR干涉仪生成的拍频信号中的非线性效应，因此在长范围（即，80 km）的非线性相位的估计不准确性所导致的残余非线性效应而恶化。在所提出的优化的去扭斜滤波器的方法中，非线性相位的估计精度提高了高阶的泰勒展开和辅助干涉仪中的时间延迟的估计的高精度使用倒谱。实验结果表明，在80 km处的反射峰幅度增加了20.5 dB，空间分辨率达到80 cm，与未进行非线性补偿的相同OFDR记录相比，空间分辨率提高了187倍。
We present a method for improving the spatial resolution and the amplitude by an optimized deskew filter in long-range optical frequency-domain reflectometry (OFDR). In a previous deskew-filter method, as the nonlinear phase estimated from an auxiliary interferometer is used to compensate for the nonlinearity effect in the beating signals generated from a main OFDR interferometer, the spatial resolution and amplitude of the reflection peak in a long range (i.e., 80 km) are deteriorated by a residual nonlinearity effect due to the estimation inaccuracy of the nonlinear phase. In the proposed optimized deskew-filter method, the estimation accuracy of the nonlinear phase is improved by the higher orders of Taylor expansion and the high accuracy of the estimation of the time delay in the auxiliary interferometer using a cepstrum. We experimentally demonstrate that the amplitude of a reflection peak at 80 km increases by 20.5 dB and that the spatial resolution is up to 80 cm, which is about 187 times enhancement when compared with that of the same OFDR trace without nonlinearity compensation.