Claims
- 1. A method for fabricating a taper, comprising:
forming a cladding layer over a substrate; forming a core layer on the cladding layer; and implanting ions in a portion of the core layer so that the implanted portion has a surface that is angled relative to a surface of the cladding layer, wherein the implanted ions cause the implanted portion to have a refractive index that is different from an unimplanted portion of the core layer.
- 2. The method of claim 1 wherein the cladding and core layers are formed using a silicon on insulator (SOI) wafer.
- 3. The method of claim 1 wherein implanting ions comprises:
forming a mask layer on the core layer; and removing a portion of the mask layer to form an angled region in the mask layer.
- 4. The method of claim 1 wherein the mask layer is formed using a gray scale lithography process.
- 5. The method of claim 4 wherein the mask layer comprises photoresist.
- 6. The method of claim 4 wherein the mask layer comprises oxide.
- 7. The method of claim 1 wherein the core layer is formed from a semiconductor material.
- 8. The method of claim 1 wherein the ions are oxygen ions.
- 9. The method of claim 1 wherein the implanted portion contacts the cladding layer.
- 10. The method of claim 1 wherein the implanted portion does not contact the cladding layer.
- 11. The method of claim 1 wherein the refractive index of the implanted portion is greater than that of the unimplanted portion of the core layer.
- 12. The method of claim 1 wherein the ions implanted in the implanted portion comprise germanium ions.
- 13. The method of claim 1 wherein the refractive index of the implanted portion is greater than that of the unimplanted portion of the core layer.
- 14. An apparatus for propagating an optical signal, the apparatus comprising:
a cladding layer; and a core disposed on a surface of the cladding layer, the core layer having a first region and a second region, the first region having a refractive index different from that of the second region, the first region has a surface that is angled relative to a surface of the cladding layer.
- 15. The apparatus of claim 14 wherein the first region and the second region are part of a semiconductor layer, the first region including added ions that reduce the first region's refractive index relative to that of the second region.
- 16. The apparatus of claim 15 wherein the ions comprise oxygen ions.
- 17. The apparatus of claim 15 wherein the second region has a portion disposed between the first region and the cladding layer
- 18. The apparatus of claim 14 wherein the refractive index of the second region is greater than that of the first region.
- 19. The apparatus of claim 14 wherein the refractive index of the second region is less than that of the first region.
- 20. The apparatus of claim 19 wherein the ions comprise germanium.
- 21. An planar lightwave circuit (PLC) comprising:
a semiconductor substrate; a cladding layer disposed on the semiconductor substrate; a core disposed on a surface of the cladding layer, the core layer having a first region and a second region, wherein the first region has a refractive index less from that of the second region and has a surface that is angled relative to a surface of the cladding layer, and wherein the second region is configured to be coupled to a waveguide; and a protective layer formed to cover at least a portion of the core layer.
- 22. The PLC of claim 23 wherein the second region has a portion disposed between the first region and the cladding layer.
- 23. The PLC of claim 23 wherein the first region and the second region are part of a semiconductor layer, the first region including implanted ions that reduce the first region's refractive index relative to that of the second region.
- 24. The PLC of claim 23 wherein the refractive index of the second region is greater than that of the first region.
- 25. The PLC of claim 23 wherein the refractive index of the second region is less than that of the first region.
- 26. The PLC of claim 27 wherein the ions comprise germanium.
- 27. 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, a cladding layer disposed on the semiconductor substrate, a core disposed on a surface of the cladding layer, the core layer having a first region and a second region, wherein the first region has a refractive index less from that of the second region and has a surface that is angled relative to a surface of the cladding layer, the second region being coupled to the optical fiber, and a protective layer formed to cover at least a portion of the core layer.
- 28. The system of claim 27 wherein the second region has a portion disposed between the first region and the cladding layer.
- 29. The system of claim 27 wherein the first region and the second region are part of a semiconductor layer, the first region including implanted ions that reduce the first region's refractive index relative to that of the second region.
- 30. The system of claim 27 wherein the first region and the second region are part of a semiconductor layer, the first region including implanted ions that increase the first region's refractive index relative to that of the second region.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is related to commonly-assigned and co-filed U.S. Patent Application No. [Attorney Docket No. 42.P13840] entitled “Method For Producing Vertical Tapers In Optical Waveguides By Over Polishing” by M. Salib, and to U.S. Patent Application No. [Attorney Docket No. 42.P13843] entitled “Epitaxial Growth For Waveguide Tapering” by M. Morse.