Ultrashort pulse reflection from fiber gratings: a numerical investigation

We consider the linear reflection of ultrashort broadband pulses by uniform and nonuniform narrowband fiber gratings. We examine the effects of grating characteristics, including peak reflectivity, bandwidth, phase response (dispersion and chirp), and apodization on the reflection of such pulses from various gratings. A symmetric transform-limited 1-ps Gaussian pulse is assumed as the ultrashort broadband input to the gratings; the reflected pulses take on significantly different shapes and vary in duration. The prominent features observed are qualitatively explained in order to gain physical insight into the nature of the ultrashort pulse response and corresponding interaction. The results of this study indicate that there is the potential for a new class of applications, including temporal pulse shaping and novel devices for optical communications systems, by combining ultrashort broadband pulses with narrowband fiber gratings.