High accuracy length measurement using high-frequency repetitions of a mode-locked fiber laser (2nd report)

Step gauge measurement using double-path interferometer

Abstract

We develop a Fabry-Perot etalon to select high-frequency parts of repetition frequency modes of a short pulsed, mode-locked fiber laser. The 2GHz repetition-modified laser is transmitted to a Michelson interferometer for measuring each distance of 75mm. The optical path of the interferometer is designed as double-path in which the separation center between two beams is located at the position of measuring probe. Using this design, we can apply the mode-locked fiber laser to artifact following contact method. The advantage of the contact method can measure variety-shape artifacts that non-contact method cannot be used, i.e. step gauge. In this report we discuss the concept and design of new double-path interferometer system.