Patent ID: 8542968

Claim:
A large-core optical fiber comprising: a core having a core radius ρ and a core index of refraction n core , wherein said core comprises a doped region having an area of at least 200 μm square; a first cladding disposed about said core, said first cladding having an outer radius ρ 1 and an index of refraction n c1 , said core and said first cladding having a difference in index of refraction Δn=n core −n c1 ; and a second cladding disposed about said first cladding, said first cladding and said second cladding having a difference in index of refraction Δn 1 , wherein the first cladding radius, ρ 1 , is greater than about 1.1ρ and less than about 2ρ, and the refractive index difference between said first cladding and said second cladding, Δn 1 , is greater than about 1.5Δn and less than about 50Δn.