Superluminal optical pulse propagation at 1.5 mu m in periodic fiber Bragggratings - art. no. 055602

We report on the experimental observation of superluminal tunneling of pico second optical pulses in a periodic fiber Bragg grating, Optical pulses of 380-ps duration, generated by an externally-modulated single-frequency erbi um-ytterbium laser operating near 1.5-mum wavelength, were propagated at a group velocity greater than similar to1.97 times the speed of light in vacu um across a 2-cm long fiber grating. Owing to the very large ratio between the thickness of the barrier (2 cm) and the wavelength of probing optical p ulses (similar to1.5 mum), our experiment allows for the observation of sup erluminal tunneling in the optical region by direct optoelectronic time-dom ain measurements.