Fluoride and oxyfluoride glasses for optical applications

This paper present some recent developments on fluoride and oxyfluoride glasses, including glass composition, basic characterizations, technology and prospects, especially the development of rare earth doped fluoride glass channel waveguides for applications requiring integrated optical components. New Heavy Metal Fluoride Glasses compositions have been investigated namely manganese-rich fluorozirconates and strontium fluorohafnates. Numerous fluorophosphate glasses have also been obtained by the incorporation of NaPO3 and Na2PO3F in the unstable MnF2–BaF2 and NbO2F–BaF2 binary glasses. NMR and electrical conductivity measurements were conducted on these glasses. Rare earth-doped channeled planar waveguides were made from the rare earth doped ZBLA (57%ZrF4–34%BaF2–(5 − x)%LaF3–4%AlF3–x%REF3) glass by ionic exchange using optical lithography. The spectroscopic properties of Pr3+ doped ZBLA planar waveguides were investigated by comparison to bulk samples. For Er3+/Ce3+ doped ZBLA channeled waveguide low background losses (0.3 dB/cm) and net gain in excess of 1 dB/cm at 1.5 μm were obtained for incident pump powers higher than 200 mW.