脉冲参量对时间门控光频域反射仪性能的影响

In order to optimize the parameter settings of the time-gated optical frequency domain reflectometer system, a time-gated optical frequency domain reflectometer experimental system was built based on the principle of optical pulse compression, theoretical analysis and experimental verification were carried out, and simulation and experimental data were obtained. The results show that when the peak power of the detected optical pulse signal and the power of the local oscillator optical signal remain unchanged, the signal-to-noise ratio of the system is only related to the chirp rate and is inversely proportional to it; when the frequency sweep range remains unchanged at 80 MHz, the phase noise of the system first decreases and then increases with the increase of the pulse width, and the minimum value is near 2.5 μs; in practical applications, under the condition of satisfying the maximum frequency sweep range of the system, the optimal system phase noise (minimum value) can be obtained by adjusting the pulse width of the frequency sweep signal. This conclusion is helpful for the parameter setting and optimization of the time-gated optical frequency domain reflectometer system.

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。