Optical frequency comb-based coherent LIDAR

摘要

A coherent laser radar that uses two coherent femtosecond fiber lasers to perform absolute ranging at long distance. One coherent femtosecond fiber lasers acts as a source and the other as a local oscillator for heterodyne detection of the return signal from a cooperative target. The system simultaneously returns a time-of-flight range measurement for coarse ranging and an interferometric range measurement for fine ranging which is insensitive to spurious reflections that can cause systematic errors. The range is measured with at least 3 μm precision in 200 μs and 5 nm precision in 60 ms over a 1.5 m ambiguity range. This ambiguity range can be extended to 30 km through reversal of signal and LO source roles.