Inverted 45 degree mirror for photonic integrated circuits
First Claim
1. A photonic integrated circuit (PIC), comprising:
- a thin film dielectric layer disposed over a substrate;
a {100} crystalline device layer disposed over the thin film dielectric layer;
an optical waveguide formed in the device layer, wherein a {110} crystal plane of the device layer forms an end facet optically coupled the optical waveguide, wherein a sidewall of the thin film dielectric layer intersects the {110} crystal plane and wherein the substrate has an etch pit including a {110} crystal plane facet disposed below the {110} crystal plane of the device layer.
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Accused Products
Abstract
Inverted 45° semiconductor mirrors as vertical optical couplers for PIC chips, particularly optical receivers and transmitters. An inverted 45° semiconductor mirror functions to couple light between a plane in the PIC chip defined by thin film layers and a direction normal to a top surface of the PIC chip where it may be generated or collected by an off-chip component, such as a wire terminal. In an exemplary embodiment, a (110) plane of a cubic crystalline semiconductor may provide a 45° facet inverted relative to a (100) surface of the semiconductor from which light is to be emitted. In further embodiments, a (110) plane may be exposed by undercutting a device layer of a semiconductor on insulator (SOI) substrate. Alternatively, a pre-etched substrate surface may be bonded to a handling wafer, thinned, and then utilized for PIC waveguide formation.
14 Citations
17 Claims
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1. A photonic integrated circuit (PIC), comprising:
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a thin film dielectric layer disposed over a substrate; a {100} crystalline device layer disposed over the thin film dielectric layer; an optical waveguide formed in the device layer, wherein a {110} crystal plane of the device layer forms an end facet optically coupled the optical waveguide, wherein a sidewall of the thin film dielectric layer intersects the {110} crystal plane and wherein the substrate has an etch pit including a {110} crystal plane facet disposed below the {110} crystal plane of the device layer. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A photonic integrated circuit (PIC), comprising:
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a thin film dielectric layer disposed over a substrate; a crystalline semiconductor device layer disposed over the thin film dielectric layer; and an optical waveguide formed in the device layer to propagate an optical mode in first directions substantially parallel to a top surface of the device layer, wherein the optical waveguide comprises a crystalline end facet formed in the device layer to reflect the optical mode to and from second directions substantially normal to the top surface of the device layer, wherein the end facet is a crystal plane oriented 45°
from the first and second directions,wherein the end facet is one side of a recess etched into the device layer, the recess forming an opposing facet on an opposite side of the end facet. - View Dependent Claims (9, 10)
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11. A method of forming a mirror in a photonic integrated circuit (PIC), the method comprising:
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forming an optical waveguide in a crystalline semiconductor device layer disposed over a thin film dielectric layer of a substrate; etching a trench through the device layer; etching a portion of the thin film dielectric layer exposed by the trench to create a recess extending between the portion of the thin film dielectric layer and the trench in the device layer; and performing a crystallographic wet etch of the device layer exposed by the etching of the thin film dielectric to form a facet oriented 45°
from a top surface of the device layer that is optically coupled to the waveguide. - View Dependent Claims (12, 13, 14)
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15. A mobile computing platform comprising:
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a processor; a memory; a display; and an photonic integrated circuit (PIC) chip comprising; a photodetector optically coupled to a first end of an optical waveguide formed in a device layer disposed over thin film dielectric layer of a substrate; a crystalline end facet formed in the device layer and optically coupled to a second end of the optical waveguide to reflect light propagated from a direction substantially normal to the top surface of the device layer, to a direction that is propagated toward the photodetector, wherein the end facet is a crystal plane oriented 45°
from normal to the top surface. - View Dependent Claims (16, 17)
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Specification