The unique carrier processes in quantum dot lasers mean that lasing can be achieved at the ground state (GS) transition wavelength or at the excited state (ES) transmission wavelength or indeed simultaneously at both wavelengths. The details depend on the device characteristics and control parameters such as the pumping current and temperature. When the lasing is from the ES only one can induce all-optical switching between the two states via optical injection into the GS. The high damping of the relaxation oscillations in these devices allows for very fast switching times, with sub-nanosecond transitions easily obtained. Such ultrafast switching times are vastly superior to those obtained with conventional semiconductor lasers and make these devices very attractive for all-optical switching applications. The interplay of the two states leads to a new dynamic regime. Near the boundary of stable locking for the injected GS, deep GS intensity dropouts are observed. Further, each dropout in the GS coincides with a burst in the ES output.

Date Published: 16 March 2015
PDF: 9 pages
Proc. SPIE 9357, Physics and Simulation of Optoelectronic Devices XXIII, 93570M (16 March 2015); doi: 10.1117/12.2078973

Published in SPIE Proceedings Vol. 9357:
Physics and Simulation of Optoelectronic Devices XXIII
Bernd Witzigmann; Marek Osiński; Fritz Henneberger; Yasuhiko Arakawa, Editor(s)