Erbium-activated silica–zirconia planar waveguides prepared by sol–gel route

Er3+ doped (100 - x)SiO2 - xZrO2 planar waveguides were prepared by the sol-gel route, with x ranging from 10 up to 30 mol%. Multilayer films doped with 0.3 mol% Er3+ ions were deposited on fused quartz substrates by the dip-coating technique. The thickness and refractive index were measured by m-line spectroscopy at different wavelengths. The fabrication protocol was optimized in order to confine one propagating mode at 1.5 ?m. Photoluminescence in the near and visible region indicated a crystalline local environment for the Er3+ ion.