Patent ID: 8055109

Claim:
An optical fiber for propagating at least one lower order mode having a wavelength, λ, while limiting propagation of higher order modes having a wavelength, λ, by providing said higher order modes with a higher loss than said at least one lower order mode at said wavelength, λ, said optical fiber comprising: a first cladding region comprising one or more cladding features configured to form a partially enclosed region, said partially enclosed region having at least one opening therein formed by one or more spaces in said partially enclosed region, said one or more features having a maximum feature size, d, and a maximum bridge width, a, said maximum bridge width in part determining the size of said one or more spaces in said partially enclosed region; and a core region surrounded by the said first cladding region, said cladding features configured to substantially confine propagation of said lower order modes to said core region, wherein said maximum bridge width, a, and said maximum feature size, d, have respective values that yield a ratio of a/λ that is at least about 5 and a ratio of d/λ that is at least about 10 thereby providing an increased effective core size, confinement of said at least one lower order mode, and reduction of said higher order modes.