Substrate ruggedized optical fiber apparatus

• US 4,444,458 A
• Filed: 05/26/1981
• Issued: 04/24/1984
• Est. Priority Date: 05/26/1981
• Status: Expired due to Term

• Current Assignee: Gould Optronics Incorporated
• Original Assignee: Gould, Inc. (Transdigm Group Incorporated)
• Inventors: Stowe, David W., Kopera, Paul M.
• Primary Examiner(s): Lee, John D.
• Application Number:
  US06/267,187
• Time in Patent Office: 1,064 Days
• Field of Search: 350/96.10, 350/96.11, 350/96.12, 350/96.13, 350/96.15, 350/96.19, 350/96.20, 350/96.21, 350/320
• US Class Current: 385/123
• CPC Class Codes: G02B 6/02061 Grating external to the fibre and in contact with the fibre, e.g. evanescently coupled, gratings applied to the fibre end mechanically induced in the fibre G02B6/02071, surface relief on the fibre G02B6/02066
• CPC Class Codes: G02B 6/02071 Mechanically induced gratings, e.g. having microbends G02B6/02066 takes precedence; mode converters G02B6/14
• CPC Class Codes: G02B 6/02209 Mounting means, e.g. adhesives, casings G02B6/02171 and G02B6/02195 take precedence
• CPC Class Codes: G02B 6/245 Removing protective coverings of light guides before coupling
• CPC Class Codes: G02B 6/2821 using lateral coupling between contiguous fibres to split or combine optical signals
• 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 6/2835 formed or shaped by thermal treatment, e.g. couplers
• CPC Class Codes: G02B 6/2843 the couplers having polarisation maintaining or holding properties polarisation preserving light guides G02B6/105
• CPC Class Codes: G02B 6/3644 the coupling means being through-holes or wall apertures

Abstract

Optical devices having one or more rigidly supported optical fibers and a method of making thereof are provided in which one or more optical fibers are interfaced with a rigid support material by molecular restructuring of interfacing surface areas of the fibers and the support material. The rigidly supported optical fiber may be fabricated by assembling a longitudinal outer surface portion of the fiber in juxtaposition with a rigid support material having a lower melting point than the fiber. This assembly may be heated to allow partial liquification of the support material and fiber along the outer surface of the fiber to allow fusing therebetween. The assembly may then be cooled below the melting point of the support material to provide a ruggedized fiber-optic assembly comprising an optical fiber fused to a rigid support material. A nonstick mold material also may be provided during assembly which has a substantially higher melting point than either the fiber or the support material. The mold may be placed in juxtaposition with the fiber to prevent the fiber from being totally embedded in the support material. Various optical devices may be formed from combinations of such rigidly supported optical fibers.

Claims

1. An optical device comprising:

(a) an optical fiber having an outer surface; and

(b) a substrate rigidly supporting said optical fiber by forming a molecular interface with a portion of said outer surface while said fiber is maintained in axial tension.

2. An optical device as recited in claim 1, wherein said substrate is formed of glass.

3. An optical device as recited in claim 2, wherein said glass substrate is substantially thicker than said fiber and said substrate and said fiber have a difference in coefficient of thermal expansion of less than 27.5×

10^-7 /°

C.

4. An optical device as recited in claim 1 wherein the softening point of said substrate is lower than the softening point of said fiber.

5. An optical device as recited in claim 1 wherein said fiber is completely embedded in said substrate.

6. An optical device as recited in claim 1, wherein a longitudinal portion of said fiber is partially embedded in and fused to said substrate, an axially extending arcuate surface area of said longitudinal portion of said fiber extending outwardly through the periphery of said substrate, said substrate and said fiber having a strain of less than or equal to 5×

10^-3 there between.

7. An optical device as recited in claim 6 wherein said outwardly extending arcuate surface area is defined by a 180°

angle extending radially outward from the axis of said fiber.

8. An optical device as recited in claim 6 wherein said outwardly extending arcuate surface area is defined by an oblique angle extending radially outward from said fiber.

9. An optical device as recited in claim 1 wherein the refractive index of said substrate is higher than the refractive index of the fiber.

10. An optical device as recited in claim 1 wherein the refractive index of said substrate is lower than the refractive index of said fiber.

11. An optical device as recited in claim 1 wherein the difference in coefficients of thermal expansion between said fiber and said substrate is less than 1×

10^-5 /°

C.

12. An optical device as recited in claim 1 wherein the coefficient of thermal expansion of said fiber and said substrate are unequal.

13. A method of fabricating a rigidly supported optical fiber device comprising the steps of:

(a) assembling a longitudinal, outer-surface portion of an optical fiber in juxtaposition with a rigid support material having a lower viscosity than said fiber;

(b) maintaining said fiber in axial tension;

(c) heating said assembly so as to allow partial softening of said support material to allow a bonded interface to be formed directly between said fiber and said support material; and

(d) cooling said assembly to allow said interface to harden to form a rigid interface.

14. The method of fabrication as recited in claim 13 wherein said rigid support material is a glass substrate.

15. The method of fabrication as recited in claim 13 further comprising the additional step of biasing said fiber and said support material toward one another during said heating and cooling of said assembly to allow an arcuate portion of said outer surface of said fiber to become embedded in said support material during fusing.

16. The method of fabrication as recited in claim 13 further comprising the additional step of positioning a mold of nonstick material in juxtaposition with said fiber prior to heating to prevent fusing of said support material about the entire outer surface of said fiber.

17. The method of fabrication as recited in claim 16 further comprising polishing the nonstick material prior to positioning said material in juxtaposition with said fiber to provide a flat mold.

18. The method of fabrication as recited in claim 13 wherein heat is applied to said assembly from a heat source positioned below said assembly.

19. The method of fabrication as recited in claim 13 wherein heat is applied to said assembly from a heat source positioned above said assembly.

20. The method of fabrication as recited in claim 13 wherein said heating step further includes moving a heating source along the length of said fiber to evenly distribute heat to the fiber and the support material.

21. An optical device comprising:

(a) an optical fiber; and

(b) a rigid support material wherein said optical fiber is maintained in axial tension while said optical fiber is positioned asymmetrically with respect to said support material and while said support material is fused to the outer surface of the fiber.

22. An optical device as recited in claim 21 wherein said support material has a configuration which varies along a longitudinal portion of the fiber.

23. An optical device as recited in claim 21 wherein said support material is a rectangularly-shaped glass substrate.

24. An optical device as recited in claim 21 wherein said fiber is a single-mode fiber.

25. An optical device as recited in claim 21 wherein said fiber is a multimode fiber.

26. An optical device as recited in claim 21 wherein said fiber is a polarization-preserving fiber.

27. An optical device as recited in claim 21 wherein said fiber is a hollow-core fiber.

28. An optical device as recited in claim 21 wherein said fiber is a gradient-index fiber.

29. An optical device as recited in claim 21 wherein said fiber is a stepped-index fiber.

30. An optical device as recited in claim 21 wherein said fiber has a melting point higher than that of said support material.

31. An optical device as recited in claim 21 further comprising alignment means for positioning said fiber with respect to said support material.

32. An optical device as recited in claim 21 further comprising means for molding said support material about a longitudinal portion of said fiber.

33. An optical device, comprising:

(a) an optical fiber;

(b) a rigid glass support material; and

(c) an interface region in which said support material is fused directly to an outer surface portion of said optical fiber, at least one of said fiber and said support material being provided with a diffusible constituent which diffuses into the other material as said support material and said outer surface portion are fused together in said interface region to provide an optical device being capable of relatively uniform etching.

34. An optical device as recited in claim 33, wherein said glass support material is substantially thicker than said fiber.

35. An optical device as recited in claim 33, wherein the softening point of said rigid support material is lower than the softening point of said fiber.

36. The optical device as recited in claim 33, wherein said fiber is completely embedded in said support material.

37. An optical device as recited in claim 33, wherein a longitudinal portion of the fiber is partially embedded in and bonded to said support material, an axially extending arcuate surface area of said longitudinal portion of said fiber extending outwardly through the periphery of said support material.

38. An optical device as recited in claim 33, wherein said support material is provided with boron as a diffusible constituent.

39. An optical device as recited in claim 38, wherein said boron from said support material has diffused into an outer bonding surface of said optical fiber by a distance of 5 Å

.