Enhanced modulation bandwidth (20 GHz) of In/sub 0.4/Ga/sub 0.6/As-GaAs self-organized quantum-dot lasers at cryogenic temperatures: role of carrier relaxation and differential gain

Spectral hole-burning and carrier-heating dynamics in InGaAs quantum-dot amplifiers

“…In order to understand the performance of QD-based devices, an investigation of the intrinsic properties of QD's is necessary. For example, it has been conjectured that carrier relaxation limits the modulation bandwidth in QD lasers [14], [15]. Previous investigations used mainly time-resolved photoluminescence spectroscopy on unprocessed thin film samples (see [16]- [19] and references therein).…”

“…Previous investigations used mainly time-resolved photoluminescence spectroscopy on unprocessed thin film samples (see [16]- [19] and references therein). Beyond relaxation oscillation experiments [4], [15] direct time-resolved measurements of carrier dynamics in QD devices under electrical injection are not yet reported.…”

Ultrafast gain dynamics in InAs-InGaAs quantum-dot amplifiers

“…Recent developments in the fabrication of self-organized QD lasers emitting at room temperature (RT) on the QD ground-state transition [2] allow for first experimental tests of their performance. Some of the most important issues of QD lasers relates to their dynamic behavior, which is conjectured to be limited by the carrier capture into and relaxation in the QD's [1], [3]. Previous work dedicated to characterize directly carrier dynamics (capture, escape, lifetime) in self-organized QD's (see, for instance, [4], [5], and references therein) used mainly time-resolved photoluminescence experiments on unprocessed samples at low temperatures in the picosecond and nanosecond regime.…”

Spectral Hole-Burning and Carrier-Heating Dynamics in Quantum-Dot Amplifiers: Comparison with Bulk Amplifiers

“…The recent achievement of fabricating InAs-based electrically pumped quantum-dot (QD) lasers [2] allows to extend these previous investigations to the quasi zero-dimensional case. Quantum-dot lasers fabricated until now do not show modulation bandwidths better than QW lasers, and are conjectured to be limited by the carrier capture into and relaxation in the QDs [2,3]. However, most of the work dedicated until now to characterize directly carrier dynamics in self-organized QDs used mainly time-resolved photoluminescence experiments on unprocessed samples at low temperatures in the picosecond and nanosecond regime.…”