Abstract

Mode-locking of an In_0.53Ga_0.47As/InP multiple quantum well laser in a surface-emitting external-cavity configuration produced ~30 ps optical pulses at 1.5 μm with average powers of 260 mW (100-MHz repetition rates) and with a broad spectral bandwidth of 20 nm. Three different compression techniques were used to reduce the width of these pulses, which initially were strongly up-chirped. The techniques were grating-pair pulse compression, negative group-velocity-dispersion (GVD) fiber pulse compression, and grating-pair compression followed by fiber compression. Grating-pair compression alone eliminated most of the chirp, reducing the pulse widths to as low as 153 fs. Then, average powers were 55mW, peak powers were >3.6 kW, and the time–bandwidth product ΔνΔt was reduced from 86 to a Fourier-transform limited valued of 0.38. Fiber compression alone, using a 400-m negative GVD fiber, reduced pulse widths to 79 fs. At the beginning of the fiber, propagation removed the chirp. Further down the fiber, pulse intensities increased and soliton-effect compression further shortened the pulse. Grating-pair compression followed by fiber compression (using the 400-m fiber) produced the shortest pulses, as small as 21 fs.

© 1991 Optical Society of America