Optical and spectroscopic characterization of Er/Yb-activated planar waveguides

Soda-lime silicate glasses doped with different percentages of Er- and Yb- oxides were produced by melting, and both planar and channel waveguides were fabricated by diluted silver ion exchange. Their optical and spectroscopic properties have been investigated, and some results are reported here. The optical parameters such as refractive index, diffusion depth and number of modes were measured by m-line technique. Absorption and fluorescence spectra were also measured; particular attention was focused on upconversion phenomena. The upconversion luminescence spectra of an Er/Yb-activated waveguide were obtained by continuous-wave excitation at 514.5 nm, as a function of the excitation power. The weak upconversion bands are assigned to the 2H9/2->4I15/2 and 4G11/2->4I15/2 transitions of the Er3+ ion. The upconversion mechanism is found to be a two-photon process. Preliminary results of gain measurements in channel waveguides showed signal enhancement at 1.5 ?m, for high input signal intensities, upon pumping at 0.98 ?m.