Sol–gel Eu3+/Tm3+ doped transparent glass–ceramic waveguides

Abstract Eu 3+ and Tm 3+ doped lanthanum fluoride and lanthanum oxyfluoride are obtained from Eu 3+ , Tm 3+ containing lanthanum fluoracetate solutions. The nature of the crystal phase obtained could be controlled by the temperature of heat treatment. Spectral characteristics of Eu 3+ doped crystal phases were sufficiently different to allow utilization of Eu 3+ as structural probes. Tm 3+ emission at the technologically important spectral region of 1450 nm could be observed for the fluoride and oxyfluoride crystal phases. The large bandwidth obtained (around 120 nm) suggests potential applications in optical amplification. SiO 2 –LaF 3 –LaOF composite materials were also prepared. It is observed that for heat treatments above 800 °C, fluorine loss, probably in the form of SiF 4 hinder the observation of Tm 3+ emission. Eu 3+ spectroscopic characteristics clearly show the evolution of a fluoride like environment to an amorphous oxide one as the temperature of heat treatment increased. Thin films obtained by dip-coating on v-SiO 2 substrates and treated at 300 °C, 500 °C and 800 °C display guided modes in the visible and infrared regions. Optical characteristics (refractive index and films thickness) were obtained at 543.5, 632.8 and 1550 nm. Attenuation as low as 1.8 dB/cm was measured at 632.8 nm.