Extensive mode mapping and novel polarization filter design for ALD grown Al2O3 ridge waveguides

In this work we report on realistic simulations aiming at extending our design knowledge on the fabrication and optimization of highly efficient integrated optical waveguide amplifiers. We focus specifically on atomic layer deposition grown Al2O3 layers which will serve as the host matrix for rare-earth ion doping and form the basic device geometry. Current study aims at identification of the physical boundaries of single mode, wavelength and polarization insensitive zones (if any) for three different Al2O3 film thicknesses of 0.5, 0.75 and 1 mu m. Beam propagation method is used for systematic width and etch depth mapping of these films. In addition, geometrical propagation characteristics of the confinement factor are also estimated by tracking the optical power along the Al2O3 ridge waveguides. Together with the technological requirements, this would give the optimal geometrical dimensions prior to microfabrication process of Er doped Al2O3 based integrated optical amplifiers for the 1.48 lm to 1.61 mu m wavelength range, within the third communication window. Our simulation efforts also reveal a potential TE and TM mode selective filter geometry, which can be fabricated using single step lithography.