A scheme is proposed for high-precision, absolute distance measurement for a theoretical arbitrary optical distance. The approach utilizes a frequency stabilized Ti:sapphirez femtosecond pulse laser to provide a phase-locked summation of discrete quasi-monochromatic light modes of consecutive frequencies, which is seen as an optical comb in the frequency domain. We describe a new way of spectrally-resolved interferometry devised to measure the optical path delay between two consecutive ultrashort pulses with high precision, which leads to an accurate means of absolute distance measurement. A FPE(Fabry-Perot Etalon) filters smaller frequency from the broad-bandwidth femtosecond laser pulse produced. The dispersive interferometry data permits the unambiguous measurement range to be significantly increased compared with the dispersive interferometry used in white light to measure an absolute distance. Preliminary experimental results are reported for a spectrally-resolved interferometry demonstrating the principle of operation and yielding a non-ambiguity range of 5.75 mm and an associated resolution of nanometer level.

Date Published: 15 November 2011
PDF: 6 pages
Proc. SPIE 8321, Seventh International Symposium on Precision Engineering Measurements and Instrumentation, 83210H (15 November 2011); doi: 10.1117/12.903718

Published in SPIE Proceedings Vol. 8321:
Seventh International Symposium on Precision Engineering Measurements and Instrumentation
Kuang-Chao Fan; Man Song; Rong-Sheng Lu, Editor(s)