Ultrarapid Optical Frequency-Domain Reflectometry Based Upon Dispersion-Induced Time Stretching: Principle and Applications

This paper reviews recent progress on a new, simple, and powerful technique for ultrahigh-speed optical frequency-domain reflectometry (OFDR), namely, time-stretching (TS)-OFDR. This method is essentially based on the use of linear-dispersion-induced frequency-to-time mapping of the target broadband spectral interferogram so that this information can be captured in real time using a single photodetection stage and a fast analog-to-digital converter. The principle of operation, design tradeoffs, performance advantages, and limitations of TS-OFDR are discussed. Recent results on the application of TS-OFDR for fiber-optics device characterization and biomedical imaging are also presented.