Patent ID: 9664849
Date: 2017-05-30
CPC Classifications: G02B,G02F,H01S

Claim:
1. 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 a plurality of holes having a diameter, d, and a center-to-center spacing, Λ, wherein the ratio d/Λ is larger than 0.4 and less than about 0.9; and a core region surrounded by said first cladding region, said plurality of holes of the first cladding region configured to substantially confine propagation of said at least one lower order mode to said core region, wherein said core region has a width of at least 20 micrometers and the outside diameter of said optical fiber is at least 200 micrometers, wherein said optical fiber comprises stress elements that are incorporated into at least some of the plurality of holes of the first cladding region, and which generate two-dimensional asymmetries and provide birefringence so that a polarization-maintaining effect for the optical fiber is obtained.