Method for fabricating a tapered optical coupling into a slab waveguide
AssigneeCalifornia Institute of Technology
InventorsAli Aldibi, Axel Scherer
Life of this patent
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Abstract
A three dimensional adiabatic taper provides a funnel for light to be coupled into high index material. The taper is formed by shadow deposition or sputtering from polysilicon, which can be used to match the refractive index of waveguiding material to which the taper is optically coupled. When designed with the correct shape and adequate smoothness, such tapers form efficient waveguide couplers. Once the light has been coupled through the adiabatic coupler into an index guide on a wafer or chip, an integral design of the transition between the index guide and photonic crystal ensures low loss coupling with a minimum of diffraction and back reflection.
Claims20
A method for fabricating a tapered optical coupling into a slab waveguide comprising:
- providing a sputtering source;
- providing at least one mask between said source and said mask;
- disposing a tapered layer of material onto a substrate which includes a waveguiding layer having a plurality of holes by means of a three dimensional funnel-shaped shadow deposition defined by said sputtering source and said at least one mask, said tapered layer extending in a first two dimensional plane and optically coupled to said waveguiding layer;
- and
- photolithographically defining a second taper in said tapered layer, said second taper extending in a second two dimensional plane intersecting said first two dimensional plane, whereby shadow deposition tapers in two different dimensions.
A method for fabricating a tapered optical coupling into a slab waveguide comprising:
- disposing material from which the optical coupling will be comprised onto a substrate, which includes a waveguiding layer, by means of a shadow mask interposed between a sputtering source of the material and the substrate, a taper of the thickness of the disposed material on the substrate defined by the combination of the sputtering source and shadow mask extending in a first direction;
- and
- photolithographically defining a second taper in the disposed material on the substrate, the second taper extending in a second direction intersecting the first direction, whereby the tapered optical coupling assume a shape with a taper in two different directions.
Dependencies are inferred from the claim text.