A compact all-fiber polarization coherent Lidar is demonstrated to simultaneously measure the velocity and depolarization ratio. In the Lidar system, a dual-polarization light beam is generated in a polarization modulator (PolM). The light beam consists of a linearly polarized optical carrier and an optical sideband with an orthogonal polarization state. If the light is depolarized, the polarization directions of the optical carrier and the sideband are rotated. Both of them can be detected along the polarization direction of the original optical carrier. In the receiver, the backscattered light along the polarization direction of the original optical carrier is selected and beats with a frequency-shifted optical local oscillator (LO) signal at a photodetector. A beat signal consisting of two single-frequency components will be generated. The velocity is extracted from the frequencies of the two single-frequency components, while the depolarization ratio can be extracted from the intensity ratio of the two single-frequency components. An experiment is carried out, in which a 159-MHz signal is applied to the PolM, and an 80-MHz signal is used to produce the frequency-shifted optical LO. Two single-frequency signals at 80 and 79 MHz are generated at the receiver and used to simultaneously measure the velocity and depolarization of a target in real time.

中文翻译：

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基于偏振调制器的紧凑型全光纤偏振相干激光雷达

一个紧凑的全光纤偏振相干激光雷达被证明可以同时测量速度和去偏振比。在激光雷达系统中，双偏振光束在偏振调制器 (PolM) 中产生。光束由线性偏振光载波和具有正交偏振态的光边带组成。如果光去偏振，则光载波和边带的偏振方向发生旋转。它们都可以沿着原始光载波的偏振方向被检测到。在接收器中，选择沿原始光载波偏振方向的反向散射光，并在光电探测器上与频移的光本地振荡器 (LO) 信号搏动。将生成由两个单频分量组成的差拍信号。速度是从两个单频分量的频率中提取的，而去极化率可以从两个单频分量的强度比中提取。进行了一项实验，其中将 159 MHz 信号应用于 PolM，并使用 80 MHz 信号产生频移光 LO。接收器产生两个 80 和 79 MHz 的单频信号，用于同时实时测量目标的速度和去极化。并且使用 80-MHz 信号来产生频移光学 LO。接收器产生两个 80 和 79 MHz 的单频信号，用于同时实时测量目标的速度和去极化。并且使用 80-MHz 信号来产生频移光学 LO。接收器产生两个 80 和 79 MHz 的单频信号，用于同时实时测量目标的速度和去极化。