The fabrication and characterization of gallium-diffused planar waveguides in sapphire are reported. Waveguides were fabricated by diffusion of 60–200-nm-thick films of gallium oxide into c -cut sapphire at 1600 °C for times ranging from 6 to 16 h. Near-field intensity profiles of the guided modes were measured at wavelengths from 488 to 850 nm, and the surface-index elevation was estimated to be up to (0.6±0.02)×10<sup>-2</sup> . Potential applications for low-threshold Ti:sapphire waveguide lasers and for optical integrated circuits with passive and active elements in sapphire are discussed.
© 2001 Optical Society of America
V. Apostolopoulos, L. M. B. Hickey, D. A. Sager, and J. S. Wilkinson, "Gallium-diffused waveguides in sapphire," Opt. Lett. 26, 1586-1588 (2001)