Research On Absolute Distance Measurement using Inter-mode Beat of Optical Frequency Comb

In this paper, absolute distance measurement using inter-mode beat of optical frequency comb was researched. The repetition frequency of optical frequency comb was locked on a rubidium clock. The non-ambiguous range was expanded by synthesizing the wavelengths. Phase difference was obtained by calculating the beat frequency signal of measuring path and reference path. Experiments using synthetic wavelength of inter mode beat were carried out. A measurement resolution of 0.01mm with 0.12 mm uncertainty was achieved in the range of (0.1-72) m. The measurement range using this method could extends to kilometers in theory and could be applied to indoor and outdoor large range measurement, and could also be used in long range target detection in space.