Frequency-modulated comb LIDAR

Abstract

Frequency-modulated continuous-wave LIDAR (FMCW LIDAR) has been widely used for both scientific and industrial tools. Here, in this report, a new class of LIDAR technique based on an optical frequency comb, named frequency-modulated comb LIDAR (FMcomb LIDAR), is proposed. Instead of using one carrier such as FMCW LIDAR, the multiple carriers from an optical frequency comb are used in FMcomb LIDAR. Because of the correlation between comb modes, each frequency-scanned comb mode can be coherently stitched, thus allowing for a resolution equivalent to scanning by many comb modes while scanning only by the comb mode spacing. In a proof-of-concept experiment, three comb modes from an electro-optic frequency comb (EO comb) are coherently stitched, showing Fourier-transform limited resolution (defined as FWHM linewidth) of 10 ps (i.e., 1.5 mm in air) for about 65 ns delay. The obtained resolution is three-times higher than that of conventional FMCW LIDAR when the same scan range is considered.