Optical frequency measurement using a ultra fast mode-locked laser

Abstract

A periodic pulse train from an ultra fast mode-locked laser can be described as a frequency “comb” of spectral lines in the frequency domain, equally separated by the pulse repetition rate. The optical frequency comb can be used in optical frequency measurements as an optical frequency “ruler”. We have measured optical frequencies of an iodine-stabilized Nd: YAG laser at 532 nm and an iodine-stabilized He-Ne laser at 633 nm. We also applied this technique to an optical frequency measurement of an acetylene-stabilized laser in the telecommunication region using a two-color mode-locked fiber laser.