W-type silica fiber with all normal dispersion for high-power coherent supercontinuum generation

Concept of utilizing W-type GeO2-doped silica fiber for high power coherent supercontinuum (SC) is firstly proposed. We reveal how the core diameter, inner cladding diameter and GeO₂ doped content of outer cladding dramatically influence dispersion characteristics of W-type fibers. W-type fiber with outer cladding of 80 % GeO2 doped silica and 5 μm core diameter can achieve all normal dispersion (ANDi) from 1.2 to 2.8 μm, and the fiber with such large core diameter can withstand high power SC. SC are numerically simulated in the W-type fiber pumped with femtosecond pulse at 1960 and 1560 nm. The results suggest that the fiber can produce SC with high coherence spanning from 1020 to 2530 nm. The Wtype silica fiber not only enables high power coherent SC generation in the near-infrared range but also facilitates the implementation of an all-fiber system.