Characteristics of high-performance 1.0 μm and 1.3 μm quantum dot lasers: impact of p-doping and tunnel injection

There is a need to understand the performance limitations and the role of special techniques to enhance quantum dot (QD) laser performance. In this context, we have examined the role of p-doping in the dots and tunnel injection of electrons into the active dots in the lasers. Utilizing these techniques, we demonstrate QD lasers with zero temperature dependence of the threshold current (T₀=∞) and the output slope efficiency and small signal modulation bandwidth ≅25 GHz. It is apparent that an optimal level of p-doping, combined with tunnel injection, will lead to lasers with high modulation bandwidth, zero chirp and very high T₀. These results are presented and discussed.