Maintaining broadband gain in a Nd3+/Yb3+co-doped silica fiber amplifier via dual-laser pumping

Abstract

We report a 30 cm long Nd³⁺/Yb³⁺ co-doped silica glass fiber amplifier with well-maintained broadband gain through simultaneous dual-laser pumping at 808 and 975 nm. By controlling the ratio of the pump power at 975 (P₉₇₅) and 808 nm (P₈₀₈), the emission band of Yb³⁺/Nd³⁺ and the energy transfer efficiency of Nd³⁺→Yb³⁺ can be well controlled; thus, a tunable broadband and flat gain in the range of 1036-1080 nm are obtained. The theoretical calculation of the energy transfer efficiency of Nd³⁺→Yb³⁺ with dual-laser pumping of 808 and 975 nm explains well the mechanism of broadband and flat gain formation in the Nd³⁺/Yb³⁺ co-doped fiber.