High frequency pulse generation using a gain-switched commercial semiconductor laser with strong external injection

Abstract

We experimentally demonstrate how strong external-injection into a commercial semiconductor diode increases the laser bandwidth such that gain-switched pulses can be generated at frequencies up to 20 GHz (which is far in excess of the lasers inherent bandwidth). The optical pulses generated have pulse widths around 15 ps, and spectral widths of 35 GHz, giving a time-bandwidth product of 0.52, which is close to the transform limit for Gaussian pulses.