Anisotropic etching of optical components

• US 6,891,685 B2
• Filed: 11/10/2001
• Issued: 05/10/2005
• Est. Priority Date: 05/17/2001
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Sioptical Inc. (Cisco Systems, Inc.)
• Inventors: Montgomery, Robert Keith, Deliwala, Shrenik
• Primary Examiner(s): Palmer, Phan T. H.
• Assistant Examiner(s): Doan, Jennifer
• Application Number:
  US09/991,371
• Publication Number:
  US 20030032286A1
• Time in Patent Office: 1,277 Days
• Field of Search: 359831-837
• US Class Current: 359/831
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 2006/12038 Glass (SiO2 based materials)
• CPC Class Codes: G02B 2006/12061 Silicon
• CPC Class Codes: G02B 2006/12097 Ridge, rib or the like
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• CPC Class Codes: G02B 2006/12107 Grating
• CPC Class Codes: G02B 2006/12114 Prism
• CPC Class Codes: G02B 2006/12135 Temperature control
• CPC Class Codes: G02B 2006/12161 Distributed feedback [DFB]
• CPC Class Codes: G02B 2006/12164 Multiplexing; Demultiplexing
• CPC Class Codes: G02B 2006/12176 Etching
• CPC Class Codes: G02B 27/285 comprising arrays of elements, e.g. microprisms
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 6/10 of the optical waveguide type G02B6/02, G02B6/24 take precedence; devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means G02F1/00; transferring the modulation of modulated light G02F2/00; optical logic elements G02F3/00; optical analogue/digital converters G02F7/00
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/12011 characterised by the arrayed waveguides, e.g. comprising a filled groove in the array section
• CPC Class Codes: G02B 6/12026 characterised by means for reducing the temperature dependence
• CPC Class Codes: G02B 6/12033 characterised by means for configuring the device, e.g. moveable element for wavelength tuning switching G02B6/35; thermo-optic devices G02F1/0147
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02B 6/1228 : Tapered waveguides, e.g. integrated spot-size transformers for coupling with fibres G02B6/305
• CPC Class Codes: G02B 6/124 : Geodesic lenses or integrated gratings
• CPC Class Codes: G02B 6/2861 : using fibre optic delay lines and optical elements associated with them, e.g. for use in signal processing, e.g. filtering delay lines in general H03H, H01P9/00; optical computing devices G06E
• CPC Class Codes: G02B 6/29349 : Michelson or Michelson/Gires-Tournois configuration, i.e. based on splitting and interferometrically combining relatively delayed signals at a single beamsplitter
• CPC Class Codes: G02B 6/29358 : Multiple beam interferometer external to a light guide, e.g. Fabry-Pérot, etalon, VIPA plate, OTDL plate, continuous interferometer, parallel plate resonator G02B6/29347, G02B6/29349, G02B6/2935, G02B6/29361 take precedence; resonator evanescently coupled to light guide G02B6/29335
• CPC Class Codes: G02B 6/34 : utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 6/4232 : using the surface tension of fluid solder to align the elements, e.g. solder bump techniques flip-chip mounting techniques in assembly of semiconductor devices H01L24/81
• CPC Class Codes: G02B 6/43 : Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
• CPC Class Codes: G02F 1/0147 : based on thermo-optic effects G02F1/132 takes precedence
• CPC Class Codes: G02F 1/0152 : using free carrier effects, e.g. plasma effect
• CPC Class Codes: G02F 1/025 : in an optical waveguide structure G02F1/017, G02F1/2257 take precedence
• CPC Class Codes: G02F 1/295 : Analog deflection from or in an optical waveguide structure]
• CPC Class Codes: G02F 2201/20 : delay line
• CPC Class Codes: H01L 27/1203 : the substrate comprising an insulating body on a semiconductor body, e.g. SOI three-dimensional layout H01L27/0688

Abstract

An anisotropically etched prism assembly including a device portion, a light coupling portion, and an alignment portion. The anisotropically etched prism assembly having a plurality of optical devices arranged in a first fixed pattern. Each pair of said plurality of optical devices spaced a first prescribed distance apart. The light coupling portion including a plurality of anisotropically etched prisms. Each one of the plurality of anisotropically etched prisms is arranged in second fixed pattern so as to correspond with a respective one of the plurality of optical devices. Each one of the pairs of said plurality of anisotropically etched prisms are spaced a second prescribed distance apart, the second prescribed distance substantially equals the first prescribed distance. The alignment portion aligns the light coupling portion and the device portion. Each one of said plurality of anisotropically etched prisms are aligned with a respective one of said plurality of optical devices.

Claims

1. A light coupling assembly, comprising:

a device portion including a plurality of optical devices arranged in a first fixed pattern within at least a portion of a silicon surface layer of a silicon-on-insulator (SOI) structure, said optical devices spaced a prescribed distance apart; and

a silicon-based, passive light coupling portion including a plurality of anisotropically etched coupling elements, said coupling elements arranged in a second, fixed pattern so as to correspond with a respective one of the plurality of optical devices, wherein the light coupling portion is disposed in an aligned arrangement with the device portion so as to couple light into each optical device.

2. The light coupling assembly of claim 1, further comprising a securing portion wherein each one of said plurality of anisotropically etched coupling elements is secured relative to a respective one of said plurality of optical devices as aligned.

3. The light coupling assembly of claim 2, wherein the securing portion includes material selected from the group consisting of an adhesive material and a bonding material.

4. The light coupling assembly as defined in claim 2 wherein the securing portion includes an atomic bonding of the device portion to the light coupling portion.

5. The light coupling assembly of claim 1, wherein each one of the plurality of anisotropically etched coupling elements and the respective one of the plurality of optical devices combine to form a hybrid active electronic and optical circuit including an active electronic device and at least one optical device.

6. The light coupling assembly of claim 5, wherein the hybrid active electronic and optical circuit comprises an input/output light coupler and an evanesoent coupling region, wherein the input/output light coupler ii formed within the silicon-based, passive light coupling portion and is associated with the at least one optical device, and wherein the evanescent coupling region is at least partially formed from a gap portion that couples the passive light coupling portion to the device portion.

7. The light coupling assembly of claim 6, wherein the evanescent coupling region includes a tapered gap portion.

8. The light coupling assembly of claim 7, wherein the tapered gap portion enhances coupling efficiency.

9. The light coupling assembly of claim 7, wherein the tapered gap portion supports a first edge of the input/output light coupler at a height that is less than 100 microns above a second edge of the input/output coupler.

10. The light coupling assembly of claim 9, wherein the second edge is in contact with a waveguide proximate the input/output coupler.

11. The light coupling assembly of claim 9, wherein the second is out of contact with a waveguide proximate the input/output coupler.

12. The light coupling assembly of claim 7, further comprising a ledge that supports the input/output light coupler above the tapered gap portion.

13. The light coupling assembly of claim 12, wherein the ledge has a height that is less than 50 microns.

14. The light coupling assembly of claim 13, wherein the ledge has a height of less than 3 microns.

15. The light coupling assembly of claim 6, wherein the input/output light coupler includes a waveguide prism.

16. The light coupling assembly of claim 7, wherein the input/output light coupler includes a waveguide grating.

17. The light coupling assembly of claim 6, wherein the evanescent coupling region is at least partially formed using an optically clear adhesive.

18. The light coupling assembly of claim 17, wherein the optically clear adhesive secures the input/output light coupler to the evanescent coupling region.

19. The light coupling assembly of claim 6, wherein the evanescent coupling region is at least partially formed from air.

20. The light coupling assembly of claim 6, wherein the at least one optical device includes an optical waveguide having an upper cladding, and the evanescent coupling region and the upper cladding are formed at least partially of the same material.

21. The light coupling assembly of claim 20, wherein the evanescent coupling region and the upper cladding are at least partially formed of glass.

22. The light coupling assembly of claim 20, wherein the evanescent coupling region and the upper cladding are at least partially formed of a polyamide.

23. The light coupling assembly of claim 20, wherein the evanescent coupling region and the upper cladding are at least partially formed of an electric insulator.

24. The light coupling assembly of claim 23, wherein the electric insulator is also used to partially define active electronics in the hybrid active electronic and optical circuit.

25. The light coupling assembly of claim 6, wherein the evanescent coupling region is at least partially formed from an optically clear polymer.

26. The light coupling assembly of claim 6, wherein the evanescent coupling region has a thickness of less than 0.5 μ

m.

27. The light coupling assembly of claim 6, wherein the input/output light coupler includes a waveguide prism.

28. The light coupling assembly of claim 6, wherein the input/output light coupler includes a waveguide grating.

29. The light coupling assembly of claim 6, wherein the input/output light coupler is at least partially formed from a wafer disposed above the active electronic device and the at least one optical device.

30. The light coupling assembly of claim 6, wherein the hybrid active electronic and optical circuit includes a focusing mirror.

31. The light coupling assembly of claim 6, wherein the input/output coupler couples light into or out of a waveguide.

32. The anisotropically etched waveguide prism assembly of claim 6, wherein the evanescent coupling region includes a substantially constant thickness gap portion.

33. The anisotropically etched waveguide prism assembly of claim 32, wherein the input/output light coupler includes a waveguide prism.

34. The anisotropically etched waveguide prism assembly of claim 33, wherein the at least one optical device includes a waveguide, the input/output light coupler includes a base, and the base is positioned to be substantially parallel to an axis of the waveguide.

35. The anisotropically etched waveguide prism assembly of claim 34, wherein the hybrid circuit includes an on-chip electronics portion positioned at a height that is substantially the same a;

a height of the base.

36. The anisotropically etched waveguide prism assembly of claim 32, wherein the input/output light coupler includes a waveguide grating.

37. The anisotropically etched waveguide prism assembly of claim 36, wherein the at least one optical device includes a waveguide, the input/output light coupler includes a base, and the base is positioned to be substantially parallel to an axis of the waveguide.

38. The anisotropically etched waveguide prism assembly of claim 37, wherein the hybrid circuit includes an on-chip electronics portion positioned at a height that is substantially the same as a height of the base.

39. The light coupling assembly of claim 5, wherein altering an electric voltage applied to the active electronic device affects a free carrier distribution in a region of the at least one optical device, and thereby changes the effective mode index of the at least one optical device.

40. The light coupling assembly of claim 39, wherein the at least one optical device includes a waveguide.

41. The light coupling assembly of claim 5, wherein the hybrid active electronic and optical circuit includes a Fabry-Perot cavity.

42. The light coupling assembly of claim 5, wherein the hybrid active electronic and optical circuit includes a wavelength division multiplexer modulator.

43. The light coupling assembly of claim 5, wherein the hybrid active electronic and optical circuit includes an evanescent coupler.

44. The light coupling assembly of claim 5, wherein the hybrid active electronic and optical circuit includes a diode.

45. The light coupling assembly of claim 5, wherein the hybrid active electronic and optical circuit includes a transistor.

46. The light coupling assembly of claim 1, wherein each anisotropically etched coupling element is a KOH etched waveguide prism.

47. The light coupling assembly of claim 1, further comprising an AWG.

48. The light coupling assembly of claim 1, further comprising at least one evanescent coupling region associated with each of the plurality of anisotropically etched coupling elements, one of the at least one evanescent coupling regions extending under at least one of said plurality of anisotropically etched coupling elements and attached to at least one of the plurality of optical devices.

49. The light coupling assembly of claim 48, wherein at least one evanescent coupling region is at least partially configured as a gap portion.

50. The light coupling assembly of claim 49, wherein the at least one evanescent coupling region includes a tapered gap portion.

51. The light coupling assembly of claim 1, wherein the light coupling assembly includes one from the group of a p-n device, a field plated device, a Schottky device, a MOSCAP, and a MOSFET.

52. A light coupling assembly, comprising:

a device portion including a plurality of optical devices arranged in a first fixed pattern within at least a portion of a silicon surface layer of a silicon-on-insulator (SOI) structure, each of said plurality of optical devices spaced by a prescribed spacing; and

a silicon-based, passive light coupling portion wafer including a plurality of etched light coupling elements, each one of the plurality of etched light coupling elements arranged in a second, fixed pattern such that the etched light coupling elements are disposed in an aligned arrangement with respective ones of the optical devices so as to couple light into the optical devices.

53. The light coupling assembly of claim 52, further comprising a securing portion wherein each of said plurality of etched light coupling elements are secured relative to a respective one of said plurality of optical devices as aligned.

54. The light coupling assembly of claim 53, wherein the securing portion includes one from the group of an adhesive or a bond.

55. The light coupling portion assembly as defined in claim 52, wherein the light coupling portion wafer includes an evanescent coupling region.

56. A method of etching a light coupling assembly, comprising:

etching a device portion include a plurality of optical devices arranged in a first fixed pattern within a silicon surface layer of a silicon-on-insulator (SOI) structure, wherein each of said plurality of optical devices is spaced by a first prescribed spacing;

etching a silicon-based, passive light coupling portion wafer including a plurality of etched light coupling elements, wherein each one of the plurality of etched light coupling elements is arranged in a second, fixed pattern so as to correspond with a respective one of the plurality of optical devices, and wherein each one of said plurality of etched light coupling elements is spaced by a second prescribed spacing, the second prescribed spacing equaling the first prescribed spacing; and

aligning the light coupling portion wafer and tire device portion, wherein each one of said plurality of etched light coupling elements is aligned with a respective one of said plurality of optical devices.