Optical frequency measurement comparison using fiber laser combs between NIMT and CMS

A NIMT optical frequency comb was compare with an Er-fiber laser comb with repetition frequency of 250 MHz made by the Center for Measurement Standards (CMS), Taiwan by simultaneously measuring the frequency of a 633 nm He-Ne laser. The difference of average frequency measurement is 283 Hz and corresponds to a relative difference of 6.0x10-13.