Evolution of localization in frequency for modulated light pulses in a recirculating fiber loop

Summary form only given. We present an experimental demonstration of the evolution of localization in frequency of the optical kicked rotor in dispersive single mode fibers, predicted previously. This localization occurs after propagation in a dispersive fiber of broad light pulses that are repeatedly kicked by a sinusoidal RF phase modulation at equally spaced locations along the fiber. The naive expectation concerning the evolution of the spectrum and the buildup of sidebands (harmonics) is that their number diffusively increases with the number of kicks, so that the spectrum continuously broadens with propagation. However due to localization the spectrum is confined, usually with an exponential signature. The focus of the present paper is the transition between the broadening and the localization regimes, and the number of kicks needed for it. The experimental system to track the evolution of localization consisted of a recirculating fiber loop comprised of a tunable erbium doped fiber amplifier, a LiNbO/sub 3/ phase modulator, a chirped fiber Bragg grating (to minimize lasing of the system), polarization controls, and an electrooptic switch.