Picosecond optical signal processing based on transmissive fiber Bragg gratings.

We report the experimental realization of an ultrafast (terahertz-bandwidth) linear optical signal processor, particularly a picosecond flat-top optical pulse shaper, based on a fiber Bragg grating (FBG) working in transmission. The used FBG design technique, based on a specially apodized linearly chirped FBG, enables the synthesis of readily feasible devices with processing bandwidths well in the terahertz range. The specific device reported here is successfully demonstrated for reshaping ultrashort (400 fs FWHM) optical Gaussian-like pulses into 2 ps flat-top pulses.