A Yu Laptev

Yb3+-doped double-clad fibers and lasers

We present results of the research and development of double-clad Yb3+-doped fibers for high-power fiber lasers. The quality of the fabricated fibers and optimization of reflecting Bragg gratings allowed us to demonstrate fiber lasers with a quantum efficiency close to 90%. These fiber lasers were used in Raman converters emitting at various wavelengths.

Effects of Yb3+ and Er3+ concentrations and doping procedure on excitation transfer efficiency in Er-Yb doped phosphosilicate fibers

We have studied the effects of preform fabrication procedure and ytterbium and erbium concentrations on the efficiency of excitation transfer from Yb3+ to Er3+ and lasing on erbium transitions in the range 1.53–1.61 μm in phosphosilicate glass fibers. The results indicate that the fabrication of fiber preforms by different MCVD-based processes has no effect on the excitation transfer efficiency. In the ranges 0.07–0.4wt % Er3+ and ∼ 0.4–8 wt % Yb3+ (Yb/Er ratio from ∼ 5 to 40), the excitation transfer efficiency is determined by the ytterbium concentration and is essentially independent of erbium concentration.

Effect of ytterbium co-doping on erbium clustering in silica-doped glass

The effect of ytterbium co-doping on erbium ion clustering in silica-based glass was studied. It was experimentally shown that the pump-to-signal conversion efficiency could be significantly increased if the number of Yb3+ ions in the fiber core was 20 times higher than the number of Er3+ ions. Estimations of the number of Er3+ ions in clusters confirmed a decrease in their clustering at high Yb concentrations.

Absorption and luminescence properties of Cr{sup 4+}-doped silica fibres

The absorption and luminescence spectra of silica fibres doped with chromium and various dopants are studied. Fibres doped with aluminium and gallium exhibit a broad (300 nm) luminescence band of Cr{sup 4+} ions at 1100 nm at room temperature. The quantum yield of luminescence is estimated to be 10{sup -4}-10{sup -5}. (optical fibres)