Fabrication and Characterization of AlGaAs-based Photonic Crystal Slab Waveguides by Precisely Controlled Self-Aligned Selective-Oxidation Process

Abstract

The oxidation process applied to the fabrication of an oxide-cladding two-dimensional AlGaAs-based photonic crystal waveguide with tapered ridge waveguides is thoroughly investigated. Combining an extremely small amount of oxidation with the tapered ridge waveguides yielded the self-aligned selective oxidation without any masking layers. This tapered ridge waveguide with partial oxidation functions like a spot size converter that reduces propagation loss and, more importantly, lessens the significant strain induced by oxidation. On the other hand, satisfactory agreement between transmission measurements of fabricated samples and three-dimensional finite-difference time-domain calculations demonstrates the high quality of the photonic crystal slab waveguide.

Numerical Design of Photonic Crystal Cavity Structure with AlAs/AlOxCladding Layers for Current-Driven Laser Diodes

“…The selective oxidation can be carried out easily with accurate control of the oxidation width by introducing H 2 O vapor through the air holes. 24) We note that the properties of a similar PC structure have been studied by Chen and Towe. 21) They investigated the effect of cladding layer thickness and number of air holes surrounding the cavity using finite-difference time-domain (FDTD) calculations in order to find a structure that has a large Q-factor.…”