Through-substrate optical coupling to photonics chips

Patent metadata

Field	Value
Publication number	US-9285554-B2
Application number	US-201213370886-A
Country	US
Kind code	B2
Filing date	Feb 10, 2012
Priority date	Feb 10, 2012
Publication date	Mar 15, 2016
Grant date	Mar 15, 2016

Abstract

An optoelectronic integrated circuit for coupling light to or from an optical waveguide formed in an optical device layer in a near-normal angle to that layer. In an embodiment, the integrated circuit comprises a semiconductor body including a metal-dielectric stack, an optical device layer, a buried oxide layer and a semiconductor substrate arranged in series between first and second opposite sides of the semiconductor body. At least one optical waveguide is formed in the optical device layer for guiding light in a defined plane in that device layer. Diffractive coupling elements are disposed in the optical device layer to couple light from the waveguide toward the second surface of the semiconductor body at a near-normal angle to the defined plane in the optical device layer. In an embodiment, an optical fiber is positioned against the semiconductor body for receiving the light from the coupling elements.

First claim

The invention claimed is:

1. An optoelectronic integrated circuit for coupling light to an external optical fiber or waveguide, comprising:
a semiconductor body including first and second opposite and parallel external surfaces, and further including a metal-dielectric stack, an optical device layer, a buried oxide layer and a semiconductor substrate arranged in series between said first and second surfaces, with the optical device layer between the semiconductor substrate and the first surface of the semiconductor body;
at least one optical waveguide formed in the optical device layer for guiding light in a defined plane in the optical device layer; and
a plurality of diffractive coupling elements disposed in the optical device layer to couple light from the waveguide, through the buried oxide layer and through the substrate, to the second external surface of the semiconductor body, opposite the first external surface thereof, at a near-normal angle to said defined plane to couple the light from the waveguide to an external optical fiber or waveguide.

2. The optoelectronic integrated circuit according to claim 1 , further comprising an array of lenses formed in the second surface of the semiconductor body to receive light from or to transmit light to the plurality of diffractive coupling elements.

3. The optoelectronic integrated circuit according to claim 1 , further comprising a metallic reflective layer formed in said metal-dielectric stack adjacent the diffractive coupling elements to redirect light to the diffractive coupling elements and therein enhance optical coupling efficiency.

4. The optoelectronic integrated circuit according to claim 1 , wherein the plurality of diffractive coupling elements comprise a grating patterned into the at least one optical waveguide to allow near-normal light reflection to and from the optical waveguide.

5. The optoelectronic integrated circuit according to claim 2 , further comprising one or more mechanical elements fabricated on the second surface of the semiconductor body to facilitate positioning an external optical fiber or optical waveguide on the semiconductor body in a position aligned with the array of lenses.

6. An optoelectronic integrated circuit for coupling light to an external optical fiber or waveguide, comprising:
a semiconductor body including first and second opposite and parallel external surfaces, and further including a metal-dielectric stack, an optical device layer, a buried oxide layer, and a semiconductor substrate arranged in series between said first and second opposite surfaces, with the optical device layer between the semiconductor substrate and the first surface of the semiconductor body;
at least one optical waveguide formed in the optical device layer for guiding light in a defined plane in the optical device layer;
a grating patterned into the optical device layer to couple light from the waveguide to the second external surface of the semiconductor body, opposite the first external surface thereof, at a near-normal angle to said defined plane; and
an array of lenses formed on the second external surface of the semiconductor body to receive light from or to direct light to the grating to couple the light from the waveguide, through the buried oxide layer and through the substrate, to an external optical fiber or waveguide.

7. The optoelectronic integrated circuit according to claim 6 , further comprising a metallic reflective layer formed in said metal-dielectric stack adjacent the grating to redirect light to the grating and therein enhance optical coupling efficiency.

8. The optoelectronic integrated circuit according to claim 7 , for use with an external waveguide having a multitude of waveguide channels, and where each of the lenses of the lens array receives light in one of said waveguide channels.

9. The optoelectronic integrated circuit according to claim 8 , wherein the lenses of the array of lenses are refractive, convex lenses lithographically patterned in the second surface of the semiconductor body.

10. The optoelectronic circuit according to claim 1 , wherein:
the second surface of the semiconductor body is a back surface of the semiconductor body;
the optical device layer, the buried oxide layer and the semiconductor layer comprise a photonic chip;
the diffractive coupling elements provide backside optical coupling from the optical waveguide fabricated on a front surface of the photonic chip through the semiconductor substrate;
the diffractive coupling elements comprise a grating patterned into the optical waveguide; and
the grating comprises facets etched into the optical device layer and filled with dielectric material, resulting in a region of alternating, silicon facets and dielectric facets.

11. The optoelectronic integrated circuit according to claim 1 , wherein:
the first surface of the semiconductor body is a front surface of the semiconductor body;
the second surface of the semiconductor body is a back surface of the semiconductor body;
the optical device layer, the buried oxide layer and the semiconductor layer comprise a photonic chip; and
the diffractive coupling elements provide backside optical coupling from the optical waveguide fabricated on a front surface of the photonic chip, through the semiconductor substrate, to the back surface of the semiconductor body.

12. An optoelectronic integrated circuit for coupling light to an external optical fiber or waveguide, comprising:
a semiconductor body including first and second opposite and parallel external surfaces, and further including a metal-dielectric stack, an optical device layer, a buried oxide layer and a semiconductor substrate arranged in series between said first and second surfaces, with the optical device layer between the semiconductor substrate and the first surface of the semiconductor body;
at least one optical waveguide formed in the optical device layer for guiding light in a defined plane in the optical device layer;
a plurality of diffractive coupling elements disposed in the optical device layer to couple light from the waveguide, through the buried oxide layer and through the substrate, to the second external surface of the semiconductor body, opposite the first external surface thereof, at a near-normal angle to said defined plane; and
one or more grooves formed in the second external surface of the semiconductor body to reflect light from the diffractive coupling elements into a direction substantially parallel with the first and second surfaces of the semiconductor body to an edge of the semiconductor body to couple the light from the waveguide to an external optical fiber or waveguide.

13. The optoelectronic integrated circuit according to claim 12 , wherein at least one of said one or more grooves is a V-shaped groove extending into the semiconductor substrate from the second surface of the semiconductor body and aligned with the diffractive coupling elements.

14. The optoelectronic integrated circuit according to claim 12 , further comprising a metallic reflective layer formed in said metal-dielectric stack adjacent the diffractive coupling elements to redirect light to the diffractive coupling elements and therein enhance optical coupling efficiency.

15. The optoelectronic integrated circuit according to claim 1 , wherein the plurality of diffractive coupling elements comprise a grating patterned into the optical waveguide to allow near-normal light reflection to and from the optical waveguide.

16. The optoelectronic integrated circuit according to claim 12 , further comprising one or more mechanical ele

Assignees

• Doany Fuad
• Lee Benjamin G
• Schow Clint L
• IBM

Inventors

• Doany Fuad
• Lee Benjamin G
• Schow Clint L

Classifications

• H10W90/00

  Package configurations · CPC title

• H01L2924/00

  Electricity · mapped topic

• H01L25/167

  Electricity · mapped topic

• G02B6/124 Primary

  Geodesic lenses or integrated gratings · CPC title

• G02B6/29323

  Coupling to or out of the diffractive element through the lateral surface of the light guide (evanescent grating couplers G02B6/29332) · CPC title