全光纤转动拉曼激光雷达光电探测系统设计

针对全光纤转动拉曼激光雷达系统的极微弱光探 测问题,以光电倍增管(PMT)为核心,设计了 一款光子计数的光电探测系统。通过阻抗匹配技术对单光子脉冲进行整形以提高单光子脉冲 稳 定性和甄别计数可靠性,微分法测试脉冲高度分布以优化选择PMT工作高压、甄 别阈 值电平等工作参数,改善光电探测系统信噪比(SNR)；以泊 松点过程的脉冲堆积非线性分析模型为 基础,搭建可精确改变相对光强的实验测试系统,测试脉冲堆积效应的作用类型和有效死时 间并进行合理非线性校正以提高其线性度。实验结果表明,设计的光电探测系统可有效探 测光子计 数率低于140MHz的微弱光信号且线性度优于1.0%,提出的优化和实验方案对此类光电探测系统具有重要的借鉴意义。

A photoelectric detection system for all-fiber rotational Raman lidar

A photoelectric detection system based on photon counting technique is designed using photomultiplier tube (PMT) for solving the detectable problem of the ultra-weak light level in all-fiber rotational Raman lidar.In order to i mp rove the stability of the single photon pulse and the reliability of discriminat ion counting,the single photon pulse waveform is reshaped by impedance matching technique,and then the optimum selections of operational parameters such as PM T high-voltage power supply,discrimination threshold level are mainly discusse d through testing pulse height distribution in differential method,so its signal -to-noise ratio is enhanced.The experimental testing system possessing the re la tive optical intensity changeability with certainty is configured,and then the action type of pulse pileup effect and the effective dead time in this system ar e experimentally tested based on pulse pileup non-linear analysis model of Pois s on point process,so the reasonable nonlinearity correction may be adopt e d to improve its linearity.Experiment results show that this photoelectric dete ction system can implement the detection of weak optical signal whose photon cou nting rate is less than 140MHz,and its linearity is better than 1.0%.The optimized and provided experimental schemes are significant for the photoelectri c detection system of this type.