Super Broadband at Telecom Wavelengths From RE-Doped SiO-TaO Glass Ceramics Planar Waveguides.

This paper reports on the preparation of Er/Yb/Tm, Er/Yb/Nd, and Er/Tm/Nd triply doped and Er-doped SiO-TaO glass ceramic nanocomposites and active planar waveguides by the sol-gel process using the dip-coating technique as deposition method. The investigation of their structural, morphological, and luminescent properties using XRD, AFM, and photoluminescence analysis, are reported here. The XRD results showed the presence of L-TaO nanocrystals dispersed in the SiO-based amorphous host for all the nanocomposites and films. The rare earth ion (RE) doping concentration affected both the crystallinity, and the crystallite sizes of the TaO dispersed into SiO-TaO nanocomposites and waveguides. AFM characterization revealed crack free and smooth surface roughness and differences in viscoelasticity on the Er-doped SiO-TaO films surface, which allows the identification of TaO nanocrystals on the SiO amorphous host. The Er doped and triply doped SiO-TaO nanocomposites displayed broad- and super broadband NIR emissions with a FWHM up to 173 nm achieved in the telecom wavelengths. The lifetime of the I emitting level of the Er-doped SiO-TaO waveguides is strongly dependent on Er concentration and an emission quenching was negligible up to 0.81 mol%. The structural and luminescent investigations indicated that RE-doped SiO-TaO glass ceramics are promising candidates for photonic applications in optical devices operating in wide wavelengths at the telecom bands.