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Physical Study of Thin Film and Monolithic Nano-Composites [SiO<sub>2</sub>: 11P<sub>2</sub>O<sub>5</sub>: 3 Al<sub>2</sub>O<sub>3</sub>: (1.2) Er (1.2, 1.8 and 3) Yb] Prepared by Sol Gel Technique, Planar Waveguide and Co-Operative Up-Conversion — Oak Academic Publishing