Time division approach to separate overlapped interference fringes of multiple pulse trains of femtosecond optical frequency comb for length measurement

In this study, we attempt the separation of overlapped interference fringes arising from multiple pulse trains of a femtosecond optical frequency comb for length measurement. Based on an optical experiment, we test the performance of the separation of two overlapped interference fringes by time division for an absolute length measurement, which is about one adjacent pulse repetition interval length. We compare our results with those of a commercial He-Ne interferometer system. The two sets of results show an agreement within 0.7 µm.