A new class of linearly chirped fiber Bragg gratings, suitable for all-fiber optical multiplication and reshaping of picosecond pulse trains, is proposed and experimentally demonstrated. Repetition-rate multiplication, based on the temporal Talbot effect, is achieved by accurate control of the grating chirp, and a suitable design of the index-modulation depth profile allows for simultaneous square-pulse shaping. A 50-ps squarelike optical pulse train at 10-GHz repetition rate is obtained, starting from a 2.5-GHz Gaussian pulse train emitted by a mode-locked Er-Yb laser.
© 2001 Optical Society of America
M. Marano, S. Longhi, P. Laporta, M. Belmonte, and B. Agogliati, "All-optical square-pulse generation and multiplication at 1.5 μm by use of a novel class of fiber Bragg gratings," Opt. Lett. 26, 1615-1617 (2001)