Four-wave mixing in a GaAs/AlAs triple-coupled multilayer cavity for novel ultrafast wavelength conversion devices

摘要

Four-wave mixing (FWM) in a GaAs/AlAs triple-coupled multilayer cavity has been studied for novel planar wavelength conversion devices. Three half-wavelength cavity layers are connected in series using GaAs/AlAs distributed Bragg reflector multilayers to yield three cavity modes with equal frequency separation. Efficient and ultrafast wavelength conversion via nondegenerate FWM can be realized even in the normal incidence configuration because of the enhanced internal electric fields of the three cavity modes. The triple-coupled cavity sample was grown by molecular beam epitaxy and wavelength conversion was successfully demonstrated by measuring the spectrum of time-resolved FWM signals generated by spectrally shaped laser pulses. We found that precise control of the layer thickness is particularly important because the structural asymmetry due to the thickness inhomogeneity produces a nondegenerate FWM signal with low intensity. The temporal response was extremely fast and was almost limited by the photon lifetime (～1 ps) of each cavity mode.