Patent ID: 8213758

Claim:
A step index optical fiber comprising: a core having a core radius ρ; a first cladding disposed about said core; and a second cladding disposed about said first cladding, said first cladding having an outer radius ρ 1 , said core and said first cladding having a difference in index of refraction Δn, and said first cladding and said second cladding having a difference in index of refraction Δn 1 , wherein (i) less than 10 modes are supported in said core, (ii) the first cladding radius, ρ 1 , is greater than about 1.1ρ and less than about 2ρ, and (iii) 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.