Optical fiber fundamental mode field expander
AssigneeHer Majesty the Queen in right of Canada, as represented by the Minister of Industry, through the Communications Research Centre Canada
InventorsFrancois Bilodeau, Bernard Malo, Stephen Mihailov
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Abstract
A device for providing an expanded mode field from a single mode optical waveguide is formed by fusing a length of single mode optical fiber with a length of fiber rod absent a cladding and adiabatically tapering the fused region. The length of single mode fiber has a core having a refractive index nco and a cladding having a refractive index ncl, wherein ncl<nco and wherein the cladding has an outer diameter ρ. The length of fiber rod absent the cladding has a refractive index of the fiber rod is substantially the same as the cladding index ncl of the single mode optical fiber. The outer diameter of the length of fiber rod is ρ, the same as the cladding diameter of the single mode fiber.
Claims11
A device for providing an expanded mode field from a single mode optical waveguide, comprising:
- a length of single mode fiber having a core with a refractive index nco and a cladding with a refractive index ncl , wherein ncl<nco and wherein the cladding has an outer diameter 2ρ;
- a length of fiber rod absent a cladding wherein the refractive index of the fiber rod is substantially the same as the cladding index ncl of the single mode optical fiber, wherein the outer diameter of the length of fiber rod is 2ρ, substantially the same as the cladding diameter of the single mode fiber;
- wherein an end of the length of single mode fiber and an end of the length of rod are fused together forming a fusion splice;
- and,
- wherein a region including the fusion splice and a portion of the fiber rod and a portion of the single mode fiber about the fusion splice are adiabatically tapered.
A device for providing an expanded mode field comprising:
- a multimode fiber rod absent a cladding fused to a single mode fiber having a same outer diameter as the multimode rod, wherein a portion of the fused fiber rod and a portion of the single mode optical fiber are adiabatically tapered such that a normalized frequency or V number of the single mode fiber portion of the fused single mode fiber is less than 0.5 wherein the single mode fiber has a core and a cladding and wherein refractive index of the cladding is substantially the same as the refractive index of the multimode fiber rod.
Dependencies are inferred from the claim text.