Directional optical waveguide couplers
AssigneeBell Telephone Laboratories, Incorporated
InventorStewart Edward Miller
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Abstract
Directional optical waveguide couplers for use with planar-form optical waveguides or optical fiber waveguides are disclosed. In the coupler arrangements, light energy propagating in a direction of interest in the core of a cladded optical waveguide is first coupled into a selected region of the cladding by a mode coupling means and then coupled out of the selected cladding region by a branching optical waveguide or power tap for subsequent conversion to a representative electrical signal. The selected region of the cladding is isolated from spurious cladding modes by a pair of stripper-absorber means to ensure that the coupled out light energy is derived only from the core-guided modes propagating in the direction of interest.
Claims11
A directional optical waveguide coupler comprising:
- a main optical waveguide comprising a core capable of transmitting light energy in at least a first direction surrounded by a layer of cladding material having an index of refraction which is less than the index of refraction of said core material;
- mode coupling means disposed at a first intermediate longitudinal position along said main optical waveguide capable of enhancing mode coupling from core-guided modes to cladding modes in said main optical waveguide;
- means for transferring out of said cladding layer the cladding modes generated by said mode coupling means and propagating in said first direction for subsequent conversion to a representative electrical signal, said transferring means being disposed at a second intermediate longitudinal position along said main optical waveguide downstream of said first intermediate longitudinal position in said first direction and having an index of refraction which is equal to or greater than the index of refraction of said cladding material of said main optical waveguide;
- a first stripper-absorber means comprising both a body of dielectric material disposed in coupling relationship with the cladding of said main optical waveguide and a light absorbing means and disposed along said main optical waveguide at a third intermediate longitudinal position upstream of said first intermediate position in said first direction for removing and absorbing cladding modes propagating therebeneath in said main optical waveguide;
- and
- a second stripper-absorber means comprising both a body of dielectric material disposed in coupling relationship with the cladding of said main optical waveguide and a light absorbing means and disposed along said main optical waveguide at a fourth intermediate longitudinal position downstream of said second intermediate position in said first direction for removing and absorbing cladding modes propagating therebeneath in said main optical waveguide.
Dependencies are inferred from the claim text.