We report all-optical switching due to state-filling in quantum dots (QDs). The switching energy is as low as 6 fJ since state-filling requires only 2 electron-hole pairs per QD. The single layer of InAs/InP QDs is inserted within a InGaAsP/InP waveguide which are processed into a Mach-Zehnder interferometric switch (MZI). A 1530-1570 nm probe beam is switched by optical excitation of one MZI-arm from above. By exciting below the InGaAsP bandgap, we prove that the refractive index nonlinearity is entirely due to state-filling in the QDs.
|Title of host publication||Proceedings of the 4th IEEE Conference on Nanotechnology, 16 -19 August 2004, Munich, Germany|
|Place of Publication||New York|
|Publication status||Published - 2004|