Rare earth-doped, high NA fluoride fibre amplifiers

Abstract

Pr-doped fluorozirconate fibre with a Δn=0.047 has been fabricated. The LP11 cut-off was at 650 nm, the minimum loss was 0.08 dB/m and the fibre had a two-point-bending median strength of 2.96%. Configured as a power amplifier, a slope efficiency of 30% was obtained, giving 212 mW of output power at 1.30 μm when counter-directionally pumped with 900 mW of 1.10 μm light. © 1993.