High-speed modulation of quantum-dot lasers

Laser heterostructures with self-assembled In0.4Ga0.6As quantum dots as the gain medium were grown by molecular beam epitaxy (MBE). The small signal modulation response of the lasers was measured in a cryogenic system with provision for DC and high-frequency biasing for optical output. The frequency response characteristics were measured at several temperatures between 40-300K and at each temperature, the measurement was repeated at several injection currents above threshold, until a saturation behavior of the response was observed. Overall, significant results were obtained.