The SRI method based on the optical frequency comb on absolute distance measurement

A novel absolute distance measurement method based on the optical frequency comb of the Ti:sapphire femtosecond laser was presented. In the spectrally-resolved interferometry (SRI), all modes interference signals of the optical frequency comb was obtained by the femtosecond light pulses traveling along different optical path between the reference and measurement arms. The interference intensity in the frequency domain was inverse Fourier-transformed into the time domain, and the phase peak was isolated by use of an appropriate Hamming window, then the phase difference which was caused by the distance was resolved in the frequency domain. The simulation results indicated that this algorithm could satisfy the demand of the small scale profile measurement with the non-ambiguity range of millimeter level, and the resolution of nanometer level. Furthermore, combined with the conventional phase ranging method, the max measurement distance of our method can be extended to several dozen meters.