Optical fiber U-turn apparatus and method

• US 6,775,436 B1
• Filed: 02/26/2002
• Issued: 08/10/2004
• Est. Priority Date: 02/26/2002
• Status: Active Grant

• Current Assignee: General Dynamics Advanced Technology Systems, Inc. (General Dynamics Corporation)
• Original Assignee: General Dynamics Advanced Technology Systems, Inc. (General Dynamics Corporation)
• Inventors: Waters, James P., Schroll, Kenneth R.
• Primary Examiner(s): Ullah, Akm Enayet
• Assistant Examiner(s): Petkovsek, Daniel
• Application Number:
  US10/083,184
• Time in Patent Office: 896 Days
• Field of Search: 385/18, 385/32, 385/36, 385/47, 385/125
• US Class Current: 385/36
• CPC Class Codes: G02B 6/2817 using reflective elements to split or combine optical signals
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 6/3827 Wrap-back connectors, i.e. containing a fibre having an U shape

Abstract

A first optical fiber, a second optical fiber, and a prism are used to turn light through 180° in a small space. The prism can be a discrete microprism or a custom prism specially made using precision molding techniques or by specially machining a section of coreless optical fiber using precision machining techniques. A precision holder or substrate can be used to facilitate molding of a prism and/or assembly of the overall apparatus.

Claims

1. An apparatus comprising:

a first optical fiber having a first end;

a first collimator having a first end and a second end, said first end of said first collimator connected to said first end of said first optical fiber;

a second optical fiber having a first end;

a second collimator having a first end and a second end, said first end of said second collimator connected to said first end of second optical fiber;

a prism connected to said second end of said first collimator and to said second end of said second collimator; and

a substrate comprising at least one groove, at least one of said first collimator and said second collimator received in said groove in optical alignment with said prism.

2. The apparatus of claim 1 wherein said substrate is a precision v-groove chip.

3. The apparatus of claim 1 wherein said substrate is formed from nickel using a LIGA process.

4. The apparatus of claim 1 wherein said substrate is precision molded plastic.

5. The apparatus of claim 1 further comprising an index-matched material connecting said first collimator to said prism.

6. The apparatus of claim 5 wherein said index-matched material comprises an index-matched adhesive.

7. The apparatus of claim 1 wherein said prism is molded in place on said substrate from index-matched material.

8. The apparatus of claim 1 wherein both of said first collimator and said second collimator are received in said groove.

9. The apparatus of claim 1 wherein said substrate further comprises a second groove, wherein the other of said first collimator and said second collimator are received in said second groove.

10. The apparatus of claim 5 wherein said index-matched material comprises a sol-gel.

11. A method for making a fiber optic U-turn device comprising a first collimator, a first optical fiber, a second collimator, a second optical fiber, a prism, and a substrate comprising at least one groove, comprising the steps of:

connecting said first collimator to said first optical fiber;

connecting said second collimator to said second optical fiber;

placing said first collimator into said groove of said substrate;

placing said second collimator onto said substrate in a predetermined orientation relative to said first collimator;

placing said prism onto said substrate in optical alignment with said first and second collimators;

connecting said first collimator to said prism; and

connecting said second collimator to said prism.

12. The method of claim 11 wherein the steps of connecting said first collimator to said prism and connecting said second collimator to said prism comprise using an index matched adhesive to bond said first and second collimators to said prism.

13. The method of claim 12 wherein said index matched adhesive comprises a sol-gel.

14. A method for making a fiber optic U-turn device, comprising the steps of:

optically coupling a first collimator to a first optical fiber;

optically coupling a second collimator to a second optical fiber;

placing said first collimator onto a substrate;

placing said second collimator onto said substrate in a predetermined orientation relative to said first collimator; and

forming a prism in-situ on said substrate in optical association with said first collimator and said second collimator.

15. The method of claim 14 wherein said step of forming said prism comprises using an index-matched material to mold a prism onto said substrate in a predetermined orientation relative to said first and second collimators such that said first and second collimators become integrally connected to said prism.

16. The method of claim 14 wherein said substrate comprises at least one groove and wherein the step of placing said first collimator onto said substrate comprises placing said first collimator into said groove.

17. A method for making a fiber optic U-turn device, comprising the steps of:

connecting a first collimator to a first optical fiber;

connecting a second collimator to a second optical fiber;

connecting a first length of coreless optical fiber to said first collimator;

connecting a second length of coreless optical fiber to said second collimator; and

forming said first and second lengths of coreless optical fiber into a prism.

18. The method of claim 17 further comprising the steps of placing said first and second collimators in side-by-side abutment;

filling the valleys formed by said step of placing with an adhesive having a refractive index matched to the refractive index of said coreless optical fiber.

19. A fiber optic U-turn device, comprising:

a first collimator;

a first optical fiber connected to said first collimator;

a second collimator;

a second optical fiber connected to- said second collimator;

a prism connected to a free end of said first collimator and a free end of said second collimator, said prism being formed from at least one section of coreless optical fiber.

20. A method for making a fiber optic U-turn device, comprising the steps of:

connecting a first collimator to a first optical fiber;

connecting a second collimator to a second optical fiber;

connecting a length of coreless optical fiber to said first and said second collimators; and

forming said length of coreless optical fiber into a prism.

21. An apparatus comprising:

a prism;

a first optical fiber having a first end, said first end of said first optical fiber coupled to said prism;

a second optical fiber having a first end, said first end of said second optical fiber coupled to said prism; and

a substrate adapted to receive said first optical fiber, said second optical fiber and said prism in predetermined optical alignment with each other,

said substrate comprising at least a first groove;

said first groove receiving at least one of said first optical fiber and said second optical fiber.

22. The apparatus of claim 21, said first groove further receiving the other of said first optical fiber and said second optical fiber.

23. The apparatus of claim 21, said substrate further comprising a second groove, said second groove receiving the other of said first optical fiber and said second optical fiber.

24. The apparatus of claim 21, further comprising a first collimator having a first end and a second end, said first end of said first collimator coupled to said prism and said second end of said first collimator coupled to said first end of said first optical fiber.

25. The apparatus of claim 24, said first groove further receiving said first collimator.

26. The apparatus of claim 24, further comprising a second collimator having a first end and a second end, said first end of said second collimator coupled to said prism and said second end of said second collimator coupled to said first end of said second optical fiber;

said first groove further receiving at least one of said first collimator and said second collimator.

27. The apparatus of claim 21 wherein said first optical fiber and said second optical fiber are in side-by-side abutment.

28. The apparatus of claim 21 wherein said substrate is a silicon v-groove chip.

29. The apparatus of claim 21 further comprising an index-matched material coupling at least one of said first and second optical fibers to said prism.

30. The apparatus of claim 29 wherein said index-matched material comprises an index-matched adhesive.

31. The apparatus of claim 21 further comprising:

a focusing lens coupled to said prism; and

a section of coreless optical fiber having a first end and a second end, said first end of said section of coreless optical fiber coupled to said focusing lens and second end of said section of coreless optical fiber coupled to said first end of said first optical fiber.

32. The apparatus of claim 31 said first groove further receiving at least one of said focusing lens and said section of coreless fiber.

33. A method for making a fiber optic U-turn device comprising a first optical fiber having a first end, a second optical fiber having a first end, a prism, and a substrate adapted to receive said first optical fiber, said second optical fiber and said prism in predetermined alignment with each other, said substrate comprising at least a first groove, said method comprising the steps of:

placing one of said first optical fiber and said second optical fiber into said first groove;

placing the other of said first optical fiber and said second optical fiber onto said substrate in predetermined alignment with said one of said first optical fiber and said second optical fiber;

positioning said prism onto said substrate in predetermined alignment with said first and second optical fibers;

optically coupling said first optical fiber with said prism; and

optically coupling said second optical fiber with said prism.

34. The method of claim 33 further comprising the steps of mechanically coupling said first optical fiber with said prism and mechanically coupling said second optical fiber with said prism.

35. The method of claim 33 further comprising the steps of:

coupling said first optical fiber to a first collimator;

coupling said first collimator to said prism;

coupling said second optical fiber to a second collimator; and

coupling said second collimator to said prism.

36. The method of claim 35 wherein said steps of connecting said first collimator to said prism and connecting said second collimator to said prism comprise using an index matched adhesive to bond said first and second collimators to said prism.

37. The method of claim 33 wherein said step of positioning said prism onto said substrate comprises molding from index-matched material said prism in-situ at a predetermined location of said substrate.

38. The method of claim 33 wherein said step of placing the other of said first optical fiber and said second optical fiber onto said substrate comprises placing the other of said first optical fiber and said second optical fiber into said first groove.

39. The method of claim 33 wherein said substrate further comprises a second groove and said step of placing the other of said first optical fiber and said second optical fiber onto said substrate comprises placing the other of said first optical fiber and said second optical fiber into said second groove.

40. A method for making a fiber optic U-turn device comprising a first optical fiber having a first end, a first collimator having a first end an a second end, a second optical fiber having a first end, a second collimator having a first end an a second end, and a substrate comprising at least a first groove said method comprising the steps of:

preparing a first subassembly by connecting said first end of said first optical fiber to said first end of said first collimator;

preparing a second subassembly by connecting said first end of said second optical fiber to said first end of said second collimator;

connecting said second end of said first collimator to a first section of coreless optical fiber;

connecting said second end of said second collimator to a second section of coreless optical fiber;

joining said first section of coreless optical fiber to said second section of coreless optical fiber; and

forming said first and second sections of coreless optical fiber into a prism.

41. The apparatus of claim 40 further comprising the steps of:

placing one of said first subassembly and said second subassembly into said first channel;

placing the other of said first subassembly and said second subassembly onto said substrate in predetermined alignment with one of said first subassembly and said second subassembly.

42. The apparatus of claim 40 further comprising the steps of:

placing said first and second collimators in side-by-side abutment; and

filling the valleys thus formed with an adhesive having a refractive index matched to the refractive index of said first and second collimators.