脉冲参量对时间门控光频域反射仪性能的影响

为了对时间门控光频域反射仪系统参量设置进行优化，采用光脉冲压缩原理搭建了时间门控光频域反射仪试验系统，进行了理论分析与实验验证，取得了仿真与实验数据。结果表明，当探测光脉冲信号的峰值功率和本振光信号功率不变时，系统信噪比只与啁啾率相关，且与其成反比；当扫频范围保持80MHz不变时，系统相位噪声随脉宽增加呈现先减小后增大的趋势，且最小值处于2.5μs附近；在实际应用中，满足系统最大扫频范围的条件下，通过调节扫频信号的脉宽，可以获得最优系统相位噪声(最小值)。这一结论对时间门控光频域反射仪系统参量设置与优化是有帮助的。

The influence of pulse parameters on the performance of time-gated digital optical frequency domain reflectometer

In order to optimize the parameter settings of the time-gated digital optical frequency domain reflectometer (TGD-OFDR) system, an experimental system was built based on the optical pulse compression reflectometry. Theoretical analysis and experimental verification were carried out, and simulation and experimental data were obtained. Both of the results show that the system signal-to-noise ratio (SNR) is only related to the chirp rate. When the pulse power of the probe light and the signal power of the local oscillator light have been set, the chirp rate increases with the SNR decreasing. And the phase noise decreases firstly and then increases with the increase of the pulse width with the minimum value of about 2.5μs when the sweep range keeps 80MHz. Hence, the optimal phase noise (minimum value) can be obtained by adjusting the pulse width with the maximum sweep frequency range of the system remains unchanged. The results have certain reference significance to the parameter optimization of the TGD-OFDR system design.