High speed gain coupled DFB laser diode integrated with MQW electroabsorption modulator

We have demonstrated stable modulation characteristics of the gain coupled distributed feedback (GC-DFB) laser diode integrated with butt-coupled InGa AsP/InGaAsP strain compensated MQW (multiple-quantum-well) modulator for hi gh speed optical transmission. For this purpose, we have adopted the InGaAs P/InGaAsP strain compensated MQW structure for the EA modulator and n-doped InGaAs absorptive grating for DFB laser. The typical threshold current and slope efficiency were about 15 mA and 0.1 mW/mA, respectively. The extinct ion ratio of fabricated integrated device was about 15 dB at -2 V, and the small signal bandwidth was shown to be around 17 GHz. We also found that th e alpha parameter becomes negative at below a -0.6 V bias voltage. We trans mitted 10 Gbps NRZ electrical signal over 90 km of standard single mode opt ical fiber (SMF). A clearly opened eye diagram was observed in the modulate d output.