Nanoscaled optical fibre obtained by the sol–gel process in the SiO2–ZrO2 system doped with rare earth ions

A SiO2–ZrO2 nanostructured optical fibre is fabricated using the chemical sol–gel method associated to the drawing process; the structural and the waveguiding properties are studied. The refractive index difference (RIP) between the core and the cladding is 0.021 for a 30 mol% ZrO2 – 70 mol% SiO2 core composition. Illumination of the fibre with a supercontinuum source (350–1750 nm) shows that the light is guided over this entire range. The measured attenuation losses are 0.7 dB/m at a 1064 nm wavelength and the calculated cutoff wavelength is 714 nm. To control the nanostructure and the geometric parameters of the fibre, a preliminary study of the SiO2–ZrO2 binary system has been done, by X-ray diffraction (XRD), differential thermal analysis (DTA), thermo gravimetric analysis (TGA), transmission electron microscopy (TEM) and scanning electron microscopy (SEM); in addition the evolution of the sol viscosity with the time is studied.