A Review of a Spectral Domain Interferometer with a Frequency Comb for Length Measurement.

This review paper deals with length measurement based on a spectral-domain interferometer (SDI) using an optical comb. The SDI can measure the optical path difference in real time by acquiring the interference spectrum in a wide spectral bandwidth. A typical SDI using a broadband light source has a limited measurement range of only several millimeters due to its short coherence length. The characteristics of the frequency comb (wide spectral bandwidth and narrow linewidth of each frequency mode) dramatically enhance the measurement range of the SDI to more than several kilometers while also enabling highly reliable measurements based on length standards. In this paper, research on a SDI using a frequency comb with a mode-locked laser, a SDI using a frequency comb with a high repetition rate, and other applications of SDIs using frequency combs are summarized. With the development of photonic technology in the future, SDIs that use a frequency comb can be expected to be more widely used in various industrial and scientific areas and more aptly to realize the 'meter' as a length standard. [ABSTRACT FROM AUTHOR]