Low-loss optical waveguides in single layers of Ga1−xAlxAs

Abstract

Waveguiding has been experimentally observed in single layers of Ga_1−xAl_xAs grown on GaAs substrates, with absorption coefficients of α=0.17 cm⁻¹ at 1.15‐μm wavelength and α=1.5 cm⁻¹ at 0.93 μm. By exploiting a gradient and a peak in the Al concentration, profile waveguiding can be obtained, in contrast with the case of a layer with a uniform Al concentration which would not support guided modes because of the higher index of refraction in the GaAs substrate.