Structure and method for coupling light between dissimilar waveguides
AssigneeCalifornia Institute of Technology
InventorLawrence Cary Gunn III
Life of this patent
Estimating the term…
Abstract
Waveguide structures can be used to efficiently optically couple a microstructure-doped waveguide with another type of waveguide despite variations in the optical modes supported by the two waveguides. Reduced backscatter and backward reflections can be achieved by tapering or progressively increasing or decreasing the confinement and/or the effective index of one or both of the waveguides over a transition region in the waveguide structure.
Claims13
An apparatus comprising integrated optics including a waveguide having a cladding region which causes light to propagate along a core region of the waveguide, said waveguide comprising:
- a microstructure-doped waveguide portion comprised of microstructures in a slab of material, said microstructures disposed in a cladding region of said doped waveguide so as to define a core region in said microstructure-doped waveguide;
- and
- an elongate waveguide portion having a core region comprised of elongate transmissive material;
- said waveguide portions optically coupled to propagate light therebetween in a transition region defined by at least one of said elongate transmissive material and said microstructures, said transition region including a core region and a cladding region;
- wherein the cladding region of the waveguide confines light propagating through the core region of the waveguide, said confinement being significantly different in said microstructure-doped waveguide portion than in said elongate waveguide portion, said waveguide portions configured such that the strength of said confinement gradually changes through said transition region.
A method comprising:
- forming a first waveguide that supports an optical mode having a first propagation constant by providing material to form a slab and forming a plurality of microstructures in the slab;
- patterning the waveguide on a substrate to provide regions having different effective refractive indices;
- forming a second waveguide without microstructures having a second propagation constant having a magnitude significantly different than the first propagation constant;
- and
- configuring the waveguides to provide an optical path between the waveguides such that the propagation constant along the optical path gradually changes from one of the propagation constants to the other.
An apparatus comprising integrated optics including a waveguide having a cladding region which causes light to propagate along a core region of the waveguide, said waveguide comprising:
- a microstructure-doped waveguide portion comprised of microstructures disposed with respect to a slab of material, said microstructures disposed in a cladding region of said doped waveguide so as to define a core region in said microstructure-doped waveguide;
- and
- an elongate waveguide portion having a core region comprised of elongate transmissive material;
- said waveguide portions optically coupled to propagate light therebetween in a transition region defined by at least one of said elongate transmissive material and said microstructures, said transition region including a core region and a cladding region;
- wherein the cladding region of the waveguide confines light propagating through the core region of the waveguide, said confinement being significantly different in said microstructure-doped waveguide portion than in said elongate waveguide portion, said waveguide portions configured such that the strength of said confinement gradually changes through said transition region.
Dependencies are inferred from the claim text.