High speed quantum dot lasers

Self-organized quantum dot lasers, grown by MBE or MOVPE, have demonstrated superior characteristics such as large differential gain, ultra-low threshold current, high output power and large output tunability. However. these devices have successfully eluded researchers in the realization of large modulation bandwidths at room temperature. Typically, a bandwidth f_{-3 dB} ∼5 to 7 GHz is measured in single-mode quantum dot lasers. In this paper, we will introduce and describe the technique of tunnel injection of carriers in quantum dot lasers and the benefits therefrom. Wc have recently demonstrated very high modulation bandwidth (>20 GHz), high T₀ (363 K in 5° < T < 60°C and 202 K in 60° < T < 100°C), and low Auger recombination coefficients (∼ 3.3 × 10^-29 cm⁶/s to 3.8 × 10^-29 cm⁶/s in the temperature range 15°C < T < 85°C) in In_0.4Ga_0.6As/GaAs self-organized quantum dot tunnel injection lasers.