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/sub -3 dB/ /spl sim/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 T/sub 0/ (363 K in 5/spl deg/ < T < 60/spl deg/C and 202 K in 60/spl deg/ < T < 100/spl deg/C), and low Auger recombination coefficients (/spl sim/ 3.3 /spl times/ 10/sup -29/ cm/sup 6//s to 3.8 /spl times/ 10/sup -29/ cm/sup 6//s in the temperature range 15/spl deg/C < T < 85/spl deg/C) in In/sub 0.4/Ga/sub 0.6/As/GaAs self-organized quantum dot tunnel injection lasers.