Simultaneous Measurement of Absolute Distance and Velocity Using a Single Electro-Optic Frequency Comb Based LiDAR

Laser-based light detection and ranging (LiDAR), which requires both high precision absolute distance measurement and velocity measurement, has been widely applied in various fields including surface profiling, remote sensing, imaging, etc. Optical frequency combs, which contain numerous frequency-stabilized comb modes, have been superior candidates as laser sources of LiDARs [1]. By stitching the comb modes, frequency modulated comb LiDAR is able to achieve simultaneous measurement of absolute distance and velocity [2]. However, the distance measurement precision of this method is usually at the magnitude of millimeter or sub-millimeter, which is insufficient for many applications. In this work, we demonstrate simultaneously absolute distance measurement and velocity measurement with high precision based on a 25.3 GHz electro-optic frequency comb (EO comb). We select three comb modes from a single EO comb to generate cascaded synthetic wavelengths that enable absolute distance measurement with <1 μm precision and 1.48 mm non-ambiguity range (NAR). The NAR could be easily extended by slightly changing the repetition rate. Simultaneous velocity measurement is realized by recording the Doppler frequency shift of the comb modes.