Absolute Distance Measurement by Self-Heterodyne EO Comb Interferometry

Abstract

In this letter, we develop a compact and all-fiber system for absolute distance measurement using self-heterodyne electro-optic (EO) comb interferometry. The repetition frequency is at the level of hundreds of MHz, $\ll$ tens of GHz (typical value of EO comb), and the non-ambiguity range is large. The individual comb mode can be resolved by the self-heterodyne interferometry, and the phases of the resulting beat notes can be used to measure the distances. Compared with the reference distance meter, the experimental results show an agreement within $4~\mu \text{m}$ in 50 m range, corresponding to $8\times 10^{-8}$ in relative.