Patent ID: 7209619

Claim:
A photonic bandgap fiber for propagating light having a wavelength, λ, comprising: a core; and a cladding disposed about said core, said cladding comprising a first plurality of ring-shaped regions defined by high index material having an index of refraction, n h , and a second plurality of ring-shaped regions having a low index of refraction, n l , said first plurality of high index ring-shaped regions having an average thickness, d, and an average periodicity, Λ, such that the ratio d/Λ is less than about 0.3, wherein said cladding has a normalized frequency ν=2πd(n h 2 −n l 2 ) 1/2 /λ that is less than about π radians and said core has a wavelength transmission band larger than about 100 nm.