Pulse source based on directly modulated laser and phase modulator

We propose the simple pulse source, in which the pulses generated by large-signal directly modulated laser diode are phase-modulated, and then compressed into short pulses by an optimized length of DCF. On the one hand, phase modulator is used to enhance the negative chirp of large-signal directly modulated pulses. On the other hand, the large-signal directly modulated pulses are used to suppress the pedestal produced by the phase modulator. Using this technique, highly stable 10-GHz 5.5-ps optical pulses are obtained, which suppress pedestal up to 20dB and have a low timing jitter of 184fs.