Chirp tailoring in Q-switched InGaAsP lasers using electroabsorption loss section

Chirp tailoring is demonstrated in Q-switched two-section InGaAsP lasers, with RF modulation applied to an electroabsorption section of high saturation intensity. The pulse time-bandwidth product is varied by a factor of ~4, by changing the DC bias of the gain section. Pulses which are almost transform-limited are obtained for the lowest biases. Gain-switching experiments performed with the same lasers only show a moderate chirp dependence with bias. The authors give theoretical background to interprete the different behaviours