High Resolution Coherent Doppler Wind Lidar Incorporating Phase-Shift Keying

A coherent Doppler wind lidar (CDWL) with spatial/temporal resolution of meter and sub-second scale is reported. Phase-shift keying (PSK) is introduced into the pulse pair to enhance the measurement efficiency, and the pulse shaping and perfect binary PSK modulation are both realized by a single Mach-Zehnder modulator (MZM). The identical intensity envelope of the paired pulses reduces the influence of amplifier's gain profile and provides a monitoring parameter for bias control, which improves the system stability in practice. Theoretical analysis and numerical simulation are conducted to illustrate the principle of the proposed method. In experiments, the bias drift of the MZM is monitored in real time. Continuous radial wind profile measurement over 800 m is demonstrated with spatial and temporal resolution of 3 m and 0.1 s, respectively.