InAs/InP Self-Assembled Quantum Dots: Wavelength Tuning and Optical Nonlinearities


  • The researchers who contributed to this work are Q. Gong, R. Prasanth, S. Dilna, E. W. Bogaart, J. J. G. M. van der Tol, E. A. Patent, P. J. van Veldhoven, G. J. Eijkemans, and J. H. Wolter This work is part of the TUC project supported by the technology programme Towards Freeband Communication Impulse.


Quantum dots (QDs, i.e., semiconductor nanocrystals) can be formed by spontaneous self-assembly during epitaxial growth of lattice-mismatched semiconductor systems. InAs QDs embedded in GaInAsP on InP are introduced, which can be continuously wavelength-tuned over the 1.55 μm region by inserting ultrathin GaAs or GaP interlayers below them. We subsequently introduce a state-filling optical nonlinearity, which only requires two electron–hole pairs per QD. We employ this nonlinearity for all-optical switching using a Mach–Zehnder interferometric switch. We find a switching energy as low as 6 fJ.