Numerical Analysis for High-Speed Hybrid- Modulation Semiconductor Laser Integrated With Passive Waveguide

The high-speed intrinsic modulation characteristics of a hybrid-modulation laser diode integrated with a passive waveguide was numerically analyzed. It was confirmed that the 3-dB intrinsic small-signal modulation bandwidth depended on the coupling coefficient of the corrugation grating kappa at the distributed feedback (DFB) section and modulation amplitude ration (MAR) at the DFB and intra-cavity loss-modulation sections. The modulation bandwidth became wider when kappa decreased and MAR increased. The maximum 3-dB E/O modulation bandwidth was more than 600 GHz when kappa and MAR were from 40 to 80 cm(-1) and 6.4 V. It remained more than 300 GHz when kappa was from 40 to 200 cm(-1) and MAR was from 3.2 to 6.4 V. Dynamic single-mode operation of the laser was demonstrated numerically with a 200-Gbit/s non-return-to-zero (NRZ) modulation signal. A clear eye-opened optical NRZ pattern with a minimum extinction ratio at the eye-opening area of more than 1.0 dB was confirmed in a wide operation range and at a higher bit rate up to 300 Gbit/s.