Broad band direct modulation for chirp AM lidar

Compared with single-pulse detecting laser radar, the Chirp AM lidar with high range resolution, high accuracy, and high ability to counter jamming, has a broad application in the future, such as laser terminal guidance, topographical mapping etc. Based on direct digital frequency synthesis technology, we design and implement a broad band linear modulation signal generator, with output frequency of 4.8 GHz, bandwidth of 600 MHz. Adopting a high-frequency modulation circuit with specially designed, we realize broad band direct modulation on an 8 W single laser diode with modulation bandwidth of 450 MHz for the first time. It has established a base for development and application of compact chirp AM lidar.