Optical low-coherence reflectometry for complete chromatic dispersion characterization of few-mode fibers

A phase-sensitive optical low-coherence reflectometry (OLCR) technique is demonstrated to simultaneously measure the absolute chromatic dispersion values of each guided LP mode of a few-mode fiber. We show that the OLCR technique requires only short samples of fiber (<1 m) and has no need for high-ratio mode converters to reach an accurate wavelength-dependent group delay evolution of every mode. As an example we present for the first time to our knowledge a direct and complete analysis of few-mode fibers with high, low, positive, and negative modal dispersion values, leading to chromatic dispersion parameters in good agreement with theoretical predictions. (c) 2007 Optical Society of America.