Fabrication of cylindrical resonant microcavities using the confinement provided by partially oxidized AlGaAs/GaAs layers

Two different interfaces for optical confinement in GaAs resonators (air/GaAs/air, air/GaAs/AlOx) are compared in cylindrical microstructures with 10 μm of diameter. The AlOx is obtained by the lateral oxidation of Al
_0.9
Ga
_0.1
As layers. The spectrum of the resonators is obtained using a tapered fiber system in the wavelength range between 1470 nm and 1610 nm. The modal separation agrees with simulations. The quality factor for the cylindrical microstructures having air/GaAs/air interface is almost twice the value for the case of AlOx interface. Since it is expected that surface recombination velocity is reduced by a factor of ten for this last case, these structures are expected to be suitable for the development of active resonators.