40 GHz hybrid semiconductor pulse generating laser (PGL) for RZ transmission

A hybrid 40 GHz semiconductor pulse generating laser suitable for long-haul RZ (return-to-zero) transmission was constructed, emitting 5.5 ps pulses of >22 dB contrast ratio, and with a BER performance equivalent to a less compact EA modulator based transmitter. The actively mode-locked hybrid laser consists of a specially designed two gain section semiconductor laser chip coupled to an external fiber Bragg-grating (FBG).