40-GHz optical pulse generation using strong external light injection of a gain-switched high-speed DBR laser diode

We demonstrate a compact 40-GHz repetition rate optical pulse source using a gain-switched distributed Bragg reflector laser diode with strong external light injection. The 8-ps output pulses are nearly transform-limited and the timing jitter is dominated, by the radio-frequency driving source. We experimentally demonstrate the dependence of the modulation efficiency and the chirp characteristic on the external injection power level.