Varying clad-core ratio fiber design for efficient lasing at 976 nm

Abstract

We propose and theoretically analyze an ytterbium-doped double-clad fiber with tapered pump cladding for efficient lasing at 976 nm. Varying, rather than uniform, clad-core ratio is designed to achieve the uniform pump-intensity profile beyond the transparent pump intensity. The output power of the proposed tapered 80/250 fiber at 976 nm can be 1 kW with an optic–optic efficiency around 70% and a peak-to-peak signal-to-noise ratio over 20 dB within 3 m long fiber under the double-pass pumping scheme.