Translator Disclaimer
1 March 2011 Capture delay and modulation bandwidth in a quantum dot laser
Author Affiliations +
We show that the carrier capture from the optical confinement layer into quantum dots (QDs) can strongly limit the modulation bandwidth ω-3 dB of a QD laser. Closed-form analytical expressions are obtained for ω-3 dB in the limiting cases of fast and slow capture. ω-3 dB is highest in the case of instantaneous capture into QDs, when the cross-section of carrier capture into a QD σn = ∞. With reducing σn, ω-3 dB decreases and becomes zero at a certain non-vanishing value σnmin. This σnmin presents the minimum tolerable capture cross-section for the lasing to occur at a given dc component j0 of the injection current density. The higher is j0, the smaller is σnmin and hence the direct modulation of the output power is possible at a slower capture. The use of multiple layers with QDs is shown to considerably improve the modulation response of the laser - the same ω-3 dB is obtained in a multi-layer structure at a much lower j0 than in a single-layer structure. At a plausible value of σn = 10-11 cm2, ω-3 dB as high as 19 GHz is attainable in a 5-QD-layer structure.
© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Levon V. Asryan, Yuchang Wu, and Robert A. Suris "Capture delay and modulation bandwidth in a quantum dot laser", Proc. SPIE 7947, Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling VIII, 794708 (1 March 2011);

Back to Top