All-optical square-pulse generation and multiplication at 1.5 mu m by use of a novel class of fiber Bragg gratings

A new class of linearly chirped fiber Bragg gratings, suitable for all-fibe r optical multiplication and reshaping of picosecond pulse trains, is propo sed and experimentally demonstrated. Repetition-rate multiplication, based on the temporal Talbot effect, is achieved by accurate control of the grati ng chirp, and a suitable design of the index-modulation depth profile allow s for simultaneous square-pulse shaping. A 50-ps squarelike optical pulse t rain at 10-GHz repetition rate is obtained, starting from a 2.5-GHz Gaussia n pulse train emitted by a mode-locked Er-Yb laser. (C) 2001 Optical Societ y of America.