Visible light source including integrated VCSELs and integrated photonic cavities
A visible light source includes a substrate, a first reflector and a second reflector configured to reflect infrared light and arranged vertically to form a vertical cavity on the substrate, an active region in the vertical cavity and configured to emit infrared light, a micro-resonator on the substrate and configured to receive the infrared light emitted by the active region and generate visible light through optical parametric oscillation, and an output coupler configured to couple the visible light generated in the micro-resonator out of the micro-resonator.
1. A visible light source comprising:
a substrate;
a first reflector and a second reflector on the substrate, wherein the first reflector and the second reflector are configured to reflect infrared light and are arranged to form a cavity in a direction perpendicular to the substrate;
an active region in the cavity, the active region configured to emit infrared light;
a micro-resonator in a layer above the active region in the direction perpendicular to the substrate, the micro-resonator including a resonator that is formed using a nonlinear material and is configured to receive the infrared light emitted by the active region and generate visible light through optical parametric oscillation in the resonator; and
an output coupler configured to couple the visible light generated in the micro-resonator out of the micro-resonator.
2. The visible light source of claim 1 , wherein:
the micro-resonator is in the cavity or outside the cavity; and
the micro-resonator is configured to receive the infrared light directly or through an input coupler.
3. The visible light source of claim 2 , wherein the input coupler or the output coupler includes a grating coupler, a dielectric scatterer, a metallic scatterer, or nano-resonators.
4. The visible light source of claim 3 , wherein the grating coupler is slanted, apodized, chirped, or a combination thereof.
5. The visible light source of claim 1 , wherein:
the micro-resonator is outside the cavity; and
the visible light source further comprises:
a waveguide optically coupled to the micro-resonator; and
an input coupler in the cavity or outside the cavity and configured to couple the infrared light emitted by the active region into the waveguide.
6. The visible light source of claim 5 , wherein the waveguide and the micro-resonator are formed in a same material layer or are on different layers.
7. The visible light source of claim 1 , wherein the micro-resonator is configured to generate the visible light through degenerate four-wave mixing (DFWM).
8. The visible light source of claim 1 , wherein each of the first reflector and the second reflector comprises a high-contrast grating, or a distributed Bragg reflector that includes dielectric layers, semiconductor layers, or both.
9. The visible light source of claim 1 , wherein the second reflector is anti-reflective for the visible light and is configured to transmit the visible light out of the visible light source.
10. The visible light source of claim 1 , wherein the micro-resonator includes a micro-ring, a micro-disk, a waveguide-based cavity, a photonic crystal point defect cavity, a photonic-crystal ring cavity, or a plasmonic resonator.
11. The visible light source of claim 1 , wherein the micro-resonator is characterized by a circular-ring shape, an oval-ring shape, an Archimedean spiral shape, another spiral shape, or a racetrack shape.
12. The visible light source of claim 1 , wherein the output coupler is configured to couple the visible light into free space or couple the visible light into a photonic integrated circuit.
13. The visible light source of claim 1 , further comprising:
a third reflector in the cavity, wherein the third reflector is partially reflective for the infrared light;
a polarization component in the cavity and configured to select a polarization mode of the infrared light; or
both the third reflector and the polarization component.
14. The visible light source of claim 13 , wherein the polarization component includes a polarizer, a waveplate, a spatially-variant polarizer, or a spatially-variant waveplate.
15. A visible light source array comprising:
a complementary metal-oxide semiconductor (CMOS) backplane including drive circuits formed thereon; and
an array of visible light sources bonded to the CMOS backplane directly or indirectly, wherein each visible light source in the array of visible light sources is individually addressable by the drive circuits and comprises:
a first reflector and a second reflector configured to reflect infrared light and form a cavity in a direction perpendicular to the CMOS backplane;
an active region in the cavity and configured to emit infrared light;
a micro-resonator in a layer above the active region in the direction perpendicular to the CMOS backplane, the micro-resonator including a resonator that is formed using a nonlinear material, is configured to resonate in a plane perpendicular to a length direction of the cavity, and is configured to receive the infrared light emitted by the active region and generate visible light through optical parametric oscillation in the resonator; and
an output coupler configured to couple the visible light generated in the micro-resonator out of the micro-resonator.
16. The visible light source array of claim 15 , wherein:
the micro-resonator is in the cavity or outside the cavity; and
the micro-resonator is configured to receive the infrared light directly or through an input coupler.
17. The visible light source array of claim 15 , wherein:
the micro-resonator is outside the cavity; and
each visible light source in the array of visible light sources further comprises:
a waveguide optically coupled to the micro-resonator; and
an input coupler in the cavity or outside the cavity and configured to couple the infrared light into the waveguide.
18. The visible light source array of claim 15 , wherein the micro-resonator includes a micro-ring, a micro-disk, a waveguide-based cavity, a photonic crystal point defect cavity, a photonic-crystal ring cavity, or a plasmonic resonator.
19. The visible light source array of claim 15 , wherein a pitch of the visible light source array is less than 50 μm, less than 30 μm, less than 20 μm, or less than 10 μm.
20. The visible light source array of claim 15 , wherein the micro-resonator is characterized by a circular-ring shape, an oval-ring shape, a spiral shape, or a racetrack shape.