Investigation of upconversion luminescence in antimony-germanate double-clad two cores optical fiber co-doped with Yb3+/Tm3+ and Yb3+/Ho3+ ions

摘要

In the paper double-clad optical fiber with two off-set cores co-doped with 1Yb(2)O(3)-0.1Tm(2)O(3) and 1Yb(2)O(3)-0.5Ho(2)O(3) has been investigated. Antimony-germanate glass was melted as a matrix for active cores. The concentration of lanthanides and their ratio have been optimized to achieve maximum upconversion emission intensity at 478 nm ((1)G(4)-> H-3(6)) and 650 nm ((1)G(4)-> F-3(4)) in glasses doped with Tm3+ ions and 545 nm and 655 nm, corresponding to the F-5(5) -> I-5(8) and F-5(4) -> I-5(8) transitions in holmium ions. The energy transfer efficiency in glasses used as optical fiber cores was eta(Tm)=56 (0.1 mol Tm2O3) and eta(Ho)=85 (0.5 mol Ho2O3), respectively. As a result of excitation of the fabricated optical fiber (lambda(exc)=976 nm), a UC luminescence spectra was obtained. Superposition of three emission bands at the wavelengths of 481 nm (Tm3+ : blue), 545 nm (Ho3+:green) and 665 nm (Tm3+, Ho3+: red) from two separated cores was measured. Influence of fiber length and excitation power on the color coordinates (CIE-1931) have been also investigated. (C) 2015 Elsevier B.V. All rights reserved.