Tunnel injection In0.4Ga0.6As/GaAs quantum dot lasers with 15 GHz modulation bandwidth at room temperature

By utilizing tunnel injection of electrons, first demonstrated in quantum well lasers, we have measured enhanced small-signal modulation bandwidth, f(-3dB), and reduced temperature sensitivity of the threshold current, characterized by T-0, in In0.4Ga0.6As/GaAs self-organized quantum dot ridge waveguide lasers. Values of f(-3dB)=15 GHz at 283 K and T-0=237 K for 318greater than or equal toTgreater than or equal to278 are measured in these devices. The differential gain at 283 K is dg/dncongruent to8.5x10(-14) cm(2) and the gain compression factor epsilon=4.5x10(-17) cm(3). (C) 2002 American Institute of Physics.