Organic crystal compound optical waveguide and methods for its fabrication

• US 5,982,961 A
• Filed: 09/16/1997
• Issued: 11/09/1999
• Est. Priority Date: 01/21/1997
• Status: Expired due to Fees

• Current Assignee: Molecular Optoelectronics Corporation
• Original Assignee: Molecular Optoelectronics Corporation
• Inventors: Pan, Feng, McCallion, Kevin J.
• Primary Examiner(s): Lee, John D.
• Assistant Examiner(s): HAO, VICKY D
• Application Number:
  US08/931,122
• Time in Patent Office: 784 Days
• Field of Search: 385/15, 385/27, 385/28, 385/30, 385/39, 385/50
• US Class Current: 385/30
• CPC Class Codes: G02B 6/2826 using mechanical machining means for shaping of the couplers, e.g. grinding or polishing grinding, polishing in general B24
• CPC Class Codes: G02B 6/2852 using tapping light guides arranged sidewardly, e.g. in a non-parallel relationship with respect to the bus light guides (light extraction or launching through cladding, with or without surface discontinuities, bent structures)
• CPC Class Codes: G02B 6/29332 Wavelength selective couplers, i.e. based on evanescent coupling between light guides, e.g. fused fibre couplers with transverse coupling between fibres having different propagation constant wavelength dependency non wavelength-selective light guide couplers G02B6/28
• CPC Class Codes: G02F 1/0118 by controlling the evanescent coupling of light from a fibre into an active, e.g. electro-optic, overlay

Abstract

An optical coupling device, or a compound waveguide, in which optical energy is coupled to or from an optical signal propagating along a transmitting waveguide is disclosed. The optical coupling device includes a thin film organic crystal waveguide positioned in optical proximity to a portion of the transmitting waveguide. The organic crystal waveguide has a first, coupling surface facing the transmitting waveguide through which the optical energy is coupled. The transmitting waveguide may be a fiber optic having at least some material removed along a side thereof to facilitate the coupling of optical energy between the fiber optic and the organic crystal waveguide. Polishing and lapping methods for producing the thin film organic crystal waveguide, with optically smooth surfaces, are also disclosed, as are organic salt implementations of the organic crystal.

Claims

1. An optical coupling device in which optical energy is coupled to or from an optical signal propagating along a transmitting waveguide, the optical coupling device comprising:

a thin film, organic crystal waveguide positioned in optical proximity to an internal portion of the transmitting waveguide and having a first, coupling surface facing toward the portion of the transmitting waveguide through which the optical energy is coupled to intensity modulate the optical signal propagating along the transmitting waveguide.

2. The optical coupling device of claim 1, wherein the transmitting waveguide comprises a fiber optic having at least some material removed along a side thereof near said portion to facilitate the coupling of optical energy to or from the fiber optic.

3. The optical coupling device of claim 2, wherein a thickness of said organic crystal waveguide measured between the first and a second, opposing surface thereof is less than 40 μ

m.

4. The optical coupling device of claim 3, wherein the thickness of said organic crystal waveguide measured between the first and second surfaces thereof is between 20 μ

m and 30 μ

m.

5. The optical coupling device of claim 2, wherein the first, coupling surface and/or a second, opposing surface of said organic crystal waveguide are polished to an optical smoothness of less than a wavelength/4, wherein the wavelength is about 1,300 nm.

6. The optical coupling device of claim 5, wherein the first and/or second surfaces are polished to an optical smoothness of less than a wavelength/4, wherein the wavelength is about 580 nm.

7. The optical coupling device of claim 2, wherein said organic crystal waveguide is formed from an organic salt.

8. The optical coupling device of claim 7, wherein the organic salt comprises DAST.

9. The optical coupling device of claim 2, further comprising:

at least one electrode disposed about said organic crystal waveguide to facilitate electro-optic operation thereof.

10. The optical coupling device of claim 1, wherein said organic crystal waveguide comprises one of a slab waveguide and a channel waveguide.

11. An optical coupling device in which optical energy is coupled to or from an optical signal propagating along a transmitting waveguide, the optical coupling device comprising:

a polished, organic crystal waveguide positioned in optical proximity to an internal portion of the transmitting waveguide and having a first, coupling surface facing toward the portion of the fiber optic through which the optical energy is coupled to intensity modulate the optical signal propagating along the transmitting wave guide.

12. The optical coupling device of claim 11, wherein the transmitting waveguide comprises a fiber optic having at least some material removed along a side thereof near said portion to facilitate the coupling of optical energy to or from the fiber optic.

13. The optical coupling device of claim 11, wherein the first, coupling surface and/or a second, opposing surface of said organic crystal waveguide are polished.

14. The optical coupling device of claim 13, wherein the organic crystal waveguide comprises a thin film waveguide, and wherein a thickness of the waveguide measured between the first and second surfaces thereof is less than 40 μ

m.

15. The optical coupling device of claim 14, wherein the thickness of the waveguide measured between the first and second surfaces thereof is between 20 μ

m and 30 μ

m.

16. The optical coupling device of claim 15, wherein the first and/or second surfaces are polished to an optical smoothness of less than a wavelength/4, wherein the wavelength is about 1,300 nm.

17. The optical coupling device of claim 16, wherein the first and/or second surfaces are polished to an optical smoothness of less than a wavelength/4, wherein the wavelength is about 580 nm.

18. The optical coupling device of claim 11, wherein the organic crystal waveguide is formed from an organic salt.

19. The optical coupling device of claim 18, wherein the organic salt comprises DAST.

20. The optical coupling device of claim 11, further comprising:

at least one electrode disposed about said organic crystal waveguide to facilitate electro-optic operation thereof.

21. The optical coupling device of claim 11, wherein the organic crystal waveguide comprises one of a slab waveguide and a channel waveguide.

22. A method for producing an optical coupling, intensity modulating device, comprising:

(a) providing a sample of an organic crystal;

(b) providing a device block having an optical signal transmitting waveguide running therethrough;

(c) polishing a first surface of the sample to a sufficient optical smoothness;

(d) affixing the sample to the device block with the first surface facing a portion of the transmitting waveguide and therefore providing a coupling surface through which optical energy is coupled to or from the transmitting waveguide to intensity modulate the optical signal; and

(e) thereafter polishing a second, opposing surface of the sample such that the sample attains a thin film thickness.

23. The method of claim 22, further comprising:

prior to said polishing (c), positioning at least one spacer around said sample to minimize lapping and/or polishing stress placed on said sample.

24. The method of claim 23, wherein the at least one spacer comprises organic crystal spacers.

25. The method of claim 22, further comprising, prior to said providing (a):

growing an organic crystal; and

cutting said sample from said grown organic crystal.

26. The method of claim 22, wherein said polishing step (c) is preceded by:

lapping the first surface of the sample.

27. The method of claim 26, wherein said polishing step (e) is preceded by:

lapping the second surface of the sample.

28. The method of claim 27, wherein the sample reaches about 50 μ

m thickness during said lapping said first surface.

29. The method of claim 28, wherein the sufficient optical smoothness of said polishing (c) comprises an optical smoothness of less than a wavelength/4, wherein the wavelength is about 580 nm.

30. The method of claim 29, wherein the thin film thickness is less than 40 μ

m.

31. The method of claim 30, wherein the sample comprises an organic salt.

32. The method of claim 31, wherein the organic salt comprises DAST.

33. The method of claim 22, wherein the sample comprises an organic salt.

34. The method of claim 33, wherein the organic salt comprises DAST.

35. The method of claim 22, wherein the thin film thickness is less than 35 μ

m.

36. The method of claim 22, further comprising:

applying at least one electrode about the sample to facilitate electro-optic operation thereof.

37. The method of claim 22, wherein transmitting waveguide comprises a fiber optic.

38. The method of claim 37, further comprising:

removing at least some material along a side of, and toward a core of, the fiber optic to facilitate coupling of the optical energy to or from the fiber optic.

39. An optical coupling, intensity modulating device produced according to the method of claim 38.

40. An optical coupling, intensity modulating device produced according to the method of claim 22.

41. A method for producing an optical coupling, intensity modulating device, comprising:

thinning an organic crystal waveguide to a thin film thickness; and

placing the organic crystal waveguide in optical proximity to a portion of a transmitting waveguide to couple optical energy thereto or therefrom to intensity modulate an optical signal propagating in the transmitting waveguide.

42. The method of claim 41, wherein said thinning comprises:

polishing said organic crystal.

43. The method of claim 42, wherein the thin film thickness is less than 40 μ

m.

44. The method of claim 43, wherein the transmitting waveguide is a fiber optic having at least some material removed therefrom along a side thereof near said portion to facilitate the coupling of optical energy to or from the fiber optic.

45. The method of claim 44, wherein the organic crystal comprises DAST.

46. An optical coupling, intensity modulating device formed according to the method of claim 45.

47. An optical coupling, intensity modulating device formed according to the method of claim 41.

48. A method for coupling optical energy to or from a transmitting waveguide, comprising:

using a thin film organic crystal waveguide placed in optical proximity to a portion of said transmitting waveguide to intensity modulate an optical signal propagating in the transmitting wave guide.

49. The method of claim 48, wherein the transmitting waveguide comprises a fiber optic having material removed therefrom along its side and toward its core and near said portion to facilitate the coupling of optical energy to or from the fiber optic.

50. The method of claim 48, wherein the thin film organic crystal waveguide has a thickness between 20 μ

m and 30 μ

m, and has an optical smoothness of a wavelength/4 wherein the wavelength is 580 nm.

51. The method of claim 50, wherein the organic crystal comprises DAST.