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Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.


Physical Sciences and Mathematics

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This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in O‘Driscoll, I et al., Appl. Phys. Lett. 91, 263506 (2007) and may be found at

This study has been supported by the Science Foundation Ireland (SFI) under Contract Nos. 01/FI/CO13 and 03/IN.1/1340, the EU project TRIUMPH (IST-027638 STP), the Irish Research Council for Science, Engineering and Technology (IRCSET), the Tyndall National Access Programme and the Irish Higher Education Authority under the PRTLI program.


The gain and phase dynamics of InAs∕GaAs quantum dot amplifiers are studied using single and two-color heterodyne pump probe spectroscopy. The relaxation of the wetting layer carrier density is shown to have a strong effect on the phase dynamics of both ground and excited state transients, while having a much weaker effect on the gain dynamics. In addition, the dynamical alpha factor may also display a constant value after an initial transient. Such behavior is strongly encouraging for reduced pattern effect operation in high speed optical networks.