Fabrication of a waveguide taper through ion implantation

• US 7,043,124 B2
• Filed: 07/23/2004
• Issued: 05/09/2006
• Est. Priority Date: 05/31/2002
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Morse, Michael T., Salib, Michael S.
• Primary Examiner(s): Lee, John D.
• Assistant Examiner(s): Stein, James D.
• Application Number:
  US10/897,891
• Publication Number:
  US 20050002630A1
• Time in Patent Office: 655 Days
• Field of Search: 385/43, 385/129, 385/131
• US Class Current: 385/43
• CPC Class Codes: G02B 6/1228 Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305
• CPC Class Codes: G02B 6/1347 using ion implantation ion implantation in glass C03C23/0055; ion implantation in general C23C
• CPC Class Codes: G02B 6/305 and having an integrated mode-size expanding section, e.g. tapered waveguide

Abstract

A method to form a taper in a semiconductor layer. In one embodiment, the semiconductor layer is formed on a cladding layer. A mask layer is formed on the semiconductor layer. The mask layer is patterned and etched to form at least an angled region and a thick region. An ion implantation process is performed so that the portion under the angled region is implanted to have an interface or surface that is angled relative to the surface of the cladding layer. This angled surface forms part of the vertical taper. The implanted region does not contact the cladding layer, leaving an unimplanted portion to serve as a waveguide. The portion under the thick region is not implanted, forming a coupling end of the taper.

Claims

1. An apparatus for propagating an optical signal, the apparatus comprising:

a cladding layer; and

a core layer disposed on a surface of the cladding layer, the core layer including an implantation region and a second region, the implantation region having a refractive index different from that of the second region, the implantation region defining an angled interface with the second region within the core layer, the angled interface angled relative to a surface of the cladding layer.

2. The apparatus of claim 1 wherein the core layer comprises a semiconductor material, and wherein the implantation region includes implanted ions that reduce the implantation region'"'"'s refractive index relative to that of the second region.

3. The apparatus of claim 2 wherein the ions comprise oxygen ions.

4. The apparatus of claim 2 wherein the second region has a portion disposed between the implantation region and the cladding layer.

5. The apparatus of claim 1 wherein the refractive index of the second region is greater than that of the implantation region.

6. The apparatus of claim 1 wherein the core layer comprises a semiconductor material and wherein the implantation region includes implanted ions that increase the implantation region'"'"'s refractive index relative to that of the second region.

7. The apparatus of claim 6 wherein the ions comprise germanium.

18. The apparatus of claim 1, wherein the angled interface defined by the implantation region within the core layer defines a tapered transition from a first waveguide section within the core layer to a second waveguide section within the core layer, the second waveguide section having a narrower cross-section than the first waveguide section.

8. An planar lightwave circuit (PLC) comprising:

a semiconductor substrate layer;

a cladding layer disposed on the semiconductor substrate layer;

a core layer disposed on a surface of the cladding layer, the core layer including an implantation region and a second region, wherein the implantation region has a refractive index different from that of the second region and defines an angled interface with the second region, the angled interface angled relative to a surface of the cladding layer, and wherein the second region is configured to be optically coupled to a waveguide; and

a protective layer formed to cover at least a portion of the core layer.

9. The PLC of claim 8 wherein the second region has a portion disposed between the implantation region and the cladding layer.

10. The PLC of claim 8 wherein the core layer is comprised of a semiconductor material and wherein the implantation region includes implanted ions that reduce the implantation region'"'"'s refractive index relative to that of the second region.

11. The PLC of claim 10 wherein the refractive index of the second region is greater than that of the implantation region.

12. The PLC of claim 8 wherein the core layer is comprised of a semiconductor material and wherein the implantation region includes implanted ions that increase the implantation region'"'"'s refractive index relative to that of the second region.

13. The PLC of claim 12 wherein the ions comprise germanium.

19. The PLC of claim 8, wherein the angled interface defined by the implantation region within the core layer defines a tapered transition from a first waveguide section within the core layer to a second waveguide section within the core layer, the second waveguide section having a narrower cross-section than the first waveguide section.

14. A system comprising:

an optical signal source;

an optical fiber having one end coupled to the optical signal source; and

an integrated circuit that includes;

a semiconductor substrate layer,

a cladding layer disposed on the semiconductor substrate layer,

a core layer disposed on a surface of the cladding layer, the core layer including an implantation region and a second region, wherein the implantation region has a refractive index different from that of the second region and defines an angled interface with the second region, the angled interface angled relative to a surface of the cladding layer, the second region being optically coupled to the optical fiber, and

a protective layer formed to cover at least a portion of the core layer.

15. The system of claim 14 wherein the second region has a portion disposed between the implantation region and the cladding layer.

16. The system of claim 14 wherein the core layer is comprised of a semiconductor material and wherein the implantation region includes implanted ions that reduce the implantation region'"'"'s refractive index relative to that of the second region.

17. The system of claim 14 wherein the implantation region and the second region are part of a semiconductor layer, the implantation region including implanted ions that increase the implantation region'"'"'s refractive index relative to that of the second region.

20. The system of claim 14, wherein the angled interface defined by the implantation region within the core layer defines a tapered transition from a first waveguide section within the core layer to a second waveguide section within the core layer, the second waveguide section having a narrower cross-section than the first waveguide section.