Giant all-optical tunable group velocity dispersion in an optical fiber

Abstract

We realize a strongly dispersive material with large tunable group velocity dispersion (GVD) in a commercially-available photonic crystal fiber. Specifically, we pump the fiber with a two-frequency pump field that induces an absorbing resonance adjacent to an amplifying resonance via the stimulated Brillouin processes. We demonstrate alloptical control of the GVD by measuring the linear frequency chirp impressed on a 28-nanosecond-duration optical pulse by the medium and find that it is tunable over the range ± 7.8 ns 2/m. The maximum observed value of the GVD is 109 times larger than that in a typical single-mode silica optical fiber. Our observations are in good agreement with a theoretical model of the process.