Low-Coherence Virtual Reference Interferometry for Dispersion Analysis

We present low-coherence virtual reference interferometry (LC-VRI) for short length (<;1 m) fiber dispersion characterization using a broadband LED source and a low-resolution spectrometer or spectrum analyzer. The LC-VRI is a simple and convenient alternative to balanced spectral interferometry (BSI), capable of measuring both first- and second-order dispersion directly from the interference pattern. The main advantage of using LC-VRI instead of BSI is that full characterization can be performed from a single spectral scan, without the need for precision control of the reference path. The technique is demonstrated for the characterization of SMF28 fiber and the results are compared with the manufacturer´s specifications and to measurements obtained using BSI. The standard deviation of the first- and second-order dispersion is found to be on the order of 10^-3 ps and 10^-4 ps/nm, respectively, for both BSI and LC-VRI.