Compact light source
AssigneeFacebook Technologies, LLC
InventorsAlexander Koshelev, Giuseppe Calafiore, Maxwell Parsons
Life of this patent
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Abstract
A thin-profile light source capable of providing polychromatic collimated light is disclosed. A waveguide propagates light along an optical path in the waveguide core. A top cladding of the waveguide is thinned so as to have a tail of the light mode propagating in the waveguide reach the end of the top cladding. A light extracting element is coupled to the top cladding. Light leaks out of the top cladding evanescently at an angle defined by a ratio of the refractive index of the light extracting element to an effective refractive index for the light mode propagating in the waveguide.
Claims20
A light source comprising:
- a waveguide comprising:
- a substrate;
- a slab core layer on the substrate;
- and
- a cladding layer on the slab core layer, the cladding layer having a thickness that varies in a direction of light propagation in the slab core layer;
- and
- a light extractor on the cladding layer, the light extractor having a refractive index higher than an effective refractive index of a mode of propagation of light in the waveguide, for evanescent out-coupling of the light from the slab core layer into the light extractor.
A collimator comprising a slab waveguide coupled to an evanescent out-coupler for out-coupling light along its optical path in the slab waveguide so as to form a collimated output light beam propagating at an angle to a plane of the slab waveguide.
A projector comprising:
- a waveguide comprising a substrate, a slab core layer on the substrate, and a cladding layer on the slab core layer, the cladding layer having a thickness that varies in a direction of light propagation in the slab core layer;
- a light extractor on the cladding layer, the light extractor having a refractive index higher than an effective refractive index of a mode of propagation of light in the waveguide, for evanescent out-coupling of the light from the slab core layer into the light extractor;
- and
- a tunable reflective device optically coupled to the light extractor for receiving and redirecting the light out-coupled by the light extractor.
Dependencies are inferred from the claim text.