Short-length high-gain ASE fiber laser at 1.54-μm by high-codoped erbium and ytterbium phosphate laser glasses

Abstract

Ytterbium only and erbium-ytterbium co-doped phosphate glass Double Clad (DC) cladding pumped Large Mode Area (LMA) core fibers are manufactured at Kigre by the “rod-in-tube” method. The ytterbium and erbium doping concentration levels in phosphate glass are as much as two orders of magnitude higher than the doping concentrations found in fused silica fiber manufactured by Modified Chemical Vapor Deposition (MCVD) method. The background loss of the fiber’s core and cladding measured ~ 0.01 dB/per cm at 1310nm. The measured absorption coefficient at 974 nm is 0.3 dB/per cm for the ytterbium-erbium co-doped fiber. Greater than 4.6 Watts CW laser output was demonstrated from the Er:Yb:glass fiber at 1535nm with a 37.4% slop efficiency and 36.3% optical efficiency. The Yb:glass fiber produced a maximum output power of 1.6 Watts in a 14cm gain length.