Composite optical phase locking technology of chirp synthetic aperture lidar

An accurate chirp synthetic aperture lidar is proven, and the chirp laser signal is generated by an optical filter selecting specific sidebands from infinite sidebands, which are generated by laser signals passing through an electro-optic phase modulator driven by a chirp signal. And the bandwidth and chirp rate of the N-th order sideband is N times as large as the chirp signal by the signal generator. Then, a chirp signal with a modulation bandwidth of 1.2 GHz and a tuning rate of 12 THz/s is obtained by selecting the positive second-order sideband by an optical filter. Next, by adopting composite optical phase-locking processing, the random phase caused by the lidar system will be well offset, and the phase is stable within 0.1rad. Finally, Laboratory imaging results show that the azimuth resolution of synthetic aperture lidar is better than 0.04 m. In the future, by applying the higher-order sideband, higher tuning rates and bandwidths can be expected.