Absolute Measurement of Baselines up to 403 m Using Heterodyne Temporal Coherence Interferometer with Optical Frequency Comb

Abstract

A heterodyne interference system is developed for baseline measurement by using an acoustic optical modulator and an optical frequency comb stabilized by a rubidium atomic clock. Temporal coherence interference occurs at discrete spatial positions, when two pulse trains overlap. An optical delay of the interferometer with a piezoelectric transducer is created to determine the peak positions of the interference fringe patterns, and the absolute distance is obtained at a high resolution of several tens of nanometers. The experimental results at baseline distances up to 403.2 m show a high reproducibility of about 6 µm.