High accuracy length measurement using high-frequency repetitions of a mode-locked fiber laser (4th report)

Step gauge measurement using double-path interferometer

Abstract

A high-frequency part of repetition frequency modes of a ultra-short pulsed, mode-locked fiber laser, is selected by a Fabry-Pérot etalon. The 15-GHz repetition-modified laser developed is transmitted to a Michelson interferometer. The optical system of the interferometer is designed as double-path beam. A center between two beams is located at the position of a measuring probe of CMM. The interference fringes generated have a temporal coherence pattern at each 5 mm of CMM′s movement and can make positioning in space. Using this design, we can apply the mode-locked fiber laser to artifacts-following contact method. The advantage of the contact method can measure variety-shape artifacts, i.e. step gauge etc, that non-contact method cannot be used.