C. S. Seibert, D. C. Hall, D. Liang and Z. A. Shellenbarger, “Reduction of AlGaAs Heterostructure High-Index-Contrast Ridge Waveguide Scattering Loss by Sidewall Smoothing Through Oxygen-Enhanced Wet Thermal Oxidation,” in IEEE Photonics Technology Letters, vol. 22, no. 1, pp. 18-20, Jan.1, 2010, doi: 10.1109/LPT.2009.2035328.
Abstract
We demonstrate the efficacy of oxidation smoothing of sidewall roughness in high-index-contrast AlGaAs heterostructure ridge waveguides via oxygen-enhanced nonselective wet thermal oxidation for reducing scattering loss. Single-mode waveguides of core widths between 1.5 and 2.2 ¿m are fabricated using both the inward growth of a ~ 600-nm sidewall-smoothing native oxide outer cladding and, for comparison, encapsulation of an unoxidized etched ridge with a ~ 600-nm deposited silicon oxide cladding layer. On average, measured loss coefficients are reduced by a factor of 2 with the oxidation smoothing process.
Keywords: Smoothing methods, Oxidation, Optical waveguides, Optical scattering, Particle scattering, Etching, Optical losses, Optical filters, Ring lasers, Waveguide lasers