Analytical Modeling of Tunnel-Junction Transistor Lasers

Compared with transistor lasers (Ms), tunnel-junction transistor lasers (TJTLs) are more easily modulated with the voltage across base-collector (BC) junction. In this work, the charge-control model and modified rate equation of TJTLs which includes the Franz-Keldysh effect and direct tunneling is developed. We conduct DC and AC analysis with our model and show that the doping concentration in the BC junction plays a key role in the capability to voltage modulate TJTLs since it affects the junction field. A trade-off between the optical power and capability of the voltage modulation emerges as a concern for designing the doping concentration. We also study the effect of the quantum well (QW) position. The result shows that the QW closer to the BC junction can obtain a higher confinement factor to achieve better output power and modulation bandwidth.

Automated summary

In this study, a charge-control model was developed for tunnel-junction transistor lasers (TJTLs). It was found that the doping concentration in the base-collector junction plays a crucial role in the voltage modulation capability of TJTLs. A trade-off between optical power and modulation capability was observed during the design of doping concentration. Additionally, it was discovered that placing the quantum well closer to the base-collector junction can enhance the output power and modulation bandwidth.