GaAs/AlAs triple-coupled cavity with InAs quantum dots for ultrafast wavelength conversion devices

We have investigated a GaAs/AlAs triple-coupled multilayer cavity structure with InAs quantum dots for an ultrafast wavelength conversion device. Three cavity modes with the resonance frequencies ω1, ω2, and ω3 were used for efficient wavelength conversion via a four-wave mixing (FWM) process. Identical frequency separation between two adjacent modes (ω1 − ω2 = ω2 − ω3) was successfully realized using a controlled lateral thickness variation across the wafer. Time-resolved FWM signals from the triple-coupled multilayer cavity were measured using 100 fs laser pulses. The incident laser pulses were divided into two pulses and each of them was spectrally shaped individually so that the input and control pulses only covered the ω1 and ω2 modes, respectively. The wavelength-converted FWM signal with a frequency of ω3 (= 2ω2 − ω1) was clearly observed when the sample was simultaneously irradiated with the input and control laser pulses.