Gain-switched pulse generation with semiconductor lasers

The generation of picosecond optical pulses using the gain-switching method is examined using two different types of current drive at 1 GHz: short-pulse drive and sinusoidal (hard RF drive). The temporal and spectral characteristics of the resulting pulses are compared. The influence of the photon lifetime in the laser cavity has been examined for both types of drive, and it is shown that the shorter the photon lifetime then the shorter the output pulse. Simple numerical simulations are shown to give useful qualitative agreement within the limits of the model, but suggest that a limiting value of gain should be included.