Linear and quadratic dispersion characterization of millimeter-length fibers and waveguides using common-path interferometry

We measured linear and quadratic dispersion on millimeter-length fibers, waveguides, and nanowires based on common-path spectral interferometry. We obtained the linear dispersion parameter, β′, with a relative precision of 1.45×10−4, and extracted the quadratic dispersion parameter, β″, from the Taylor expansion of β′. β″ values show a discrepancy of <1% when compared with simulation as well as with measurement results obtained by a conventional Michelson interferometer. Using this method, we experimentally confirmed the sign inversion of the group velocity dispersion of AlGaAs nanowires for what is believed to be the first time.