In this paper, we proposed a kind of novel optical time-domain reflectometer (OTDR) which employed the linear frequency modulation (LFM), the fractional Fourier transform (FrFT), and electrical domain frequency division multiplexing (FDM) technologies. In our proposed OTDR, the intensity of the probe pulse was modulated by the LFM signal. At the receiver of the OTDR, the LFM signal was recovered through FrFT after the direct detection. The LFM and FrFT were helpful to overcome the deterioration induced by the multipath interference of Rayleigh backscattering and improve the signal-to-noise ratio (SNR) of the backscattered probe signal to realize a higher dynamic range (DR). With the FDM technology, the DR could be expanded furthermore. Experiments showed that about 11dB DR improvement was realized by our method with the same spatial resolution (SR) compared with a single pulse OTDR.

中文翻译：

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基于LFM信号和FDM的高动态范围OTDR

在本文中，我们提出了一种采用线性频率调制（LFM）、分数阶傅里叶变换（FrFT）和电域频分复用（FDM）技术的新型光时域反射计（OTDR）。在我们提出的 OTDR 中，探测脉冲的强度由 LFM 信号调制。在 OTDR 的接收端，LFM 信号在直接检测后通过 FrFT 恢复。LFM和FrFT有助于克服瑞利背向散射的多径干扰引起的恶化，提高背向散射探测信号的信噪比（SNR），实现更高的动态范围（DR）。借助 FDM 技术，可以进一步扩展 DR。