Violet and blue upconversion-emission from erbium-doped ZBLAN-fibers with red diode laser pumping

Abstract Violet (402 nm) and blue (470 nm) upconversion-emission with powers of several 10 μW from Er 3+ :ZBLAN fibers under red laser pumping have been obtained. Efficient red-to-violet and red-to-blue upconversion was found using laser diodes at 638 nm, a helium–neon-laser at 633 nm, and a tunable DCM-dye-laser. Pumping at the optimal excitation wavelength at 638 nm, the upconversion emission exhibited a strongly saturated dependence of the pump power. The upconversion excitation scheme in Er 3+ :ZBLAN is discussed.