Refractive index grating manufacturing process

• US 6,532,327 B1
• Filed: 03/13/2001
• Issued: 03/11/2003
• Est. Priority Date: 03/13/2001
• Status: Expired due to Fees

• Current Assignee: Proximion Fiber Systems AB
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: LaBrake, Dwayne L., Cowher, John Thomas, Pepin, Ronald Phillip, LeBlanc, Stephen Paul, Dower, William Vogel, Walker, Christopher B. Jr., Gates, Brian John, Cronk, Bryon James, Nelson, Brian Kenneth, Gatica, Anthony William
• Primary Examiner(s): Healy, Brian
• Application Number:
  US09/804,767
• Publication Number:
  US 20030039440A1
• Time in Patent Office: 728 Days
• Field of Search: 385/37, 385/134, 385/135, 385/136, 385/137, 385/147, 430/290
• US Class Current: 385/37
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29C 48/15 incorporating preformed parts or layers, e.g. extrusion moulding around inserts
• CPC Class Codes: C03C 25/106 Single coatings
• CPC Class Codes: C03C 25/12 General methods of coating; Devices therefor
• CPC Class Codes: G02B 6/02152 involving moving the fibre or a manufacturing element, stretching of the fibre G02B6/02147 takes precedence
• CPC Class Codes: G02B 6/245 Removing protective coverings of light guides before coupling
• CPC Class Codes: G02B 6/3616 Holders, macro size fixtures for mechanically holding or positioning fibres, e.g. on an optical bench supporting carriers of a microbench type G02B6/3648; micromanipulators B25J7/00; cassettes, bobbins G02B6/4439
• CPC Class Codes: G02B 6/3636 the mechanical coupling means being grooves G02B6/3652 takes precedence
• CPC Class Codes: G03F 7/001 Phase modulating patterns, e.g. refractive index patterns
• CPC Class Codes: G03F 7/24 Curved surfaces G03F7/70 takes precedence

Abstract

A method for manufacturing an optical fiber refractive index grating. The method comprises the steps of, providing a substantially twist-free length of an optical fiber between a first spool and a second spool before attaching the first spool and the second spool to a support having a first surface opposite a second surface. The support and spools provide a filament organizer including the first spool as a lockable spool and the second spool as a rotary spool. The filament organizer further comprises a tensioner coupled to the rotary spool to apply tension to at least a central portion of the length of an optical fiber disposed between the lockable spool and the rotary spool. After removing a buffer coating from the central portion of an optical fiber and applying a controlled tension to the central portion of the optical fiber, changes are made to the refractive index characteristics of the central portion during exposure to an interference pattern of high intensity actinic radiation, to produce the refractive index grating.

Claims

1. A method for manufacturing an optical fiber refractive index grating, comprising the steps of:

providing a length of an optical fiber between a first spool and a second spool;

attaching said first spool and said second spool to a support, having a first surface opposite a second surface, to provide a filament organizer including said first spool as a lockable spool and said second spool as a rotary spool, said filament organizer further comprising a tensioner coupled to said rotary spool to apply tension to at least a central portion of said length of an optical fiber disposed between said lockable spool and said rotary spool;

removing at least a buffer coating from said central portion of an optical fiber;

applying a controlled tension to said central portion of an optical fiber; and

changing the refractive index characteristics of said central portion during exposure of said central portion to an interference pattern of actinic radiation, to produce said refractive index grating.

2. The method of claim 1 wherein said length of optical fiber is substantially twist free.

3. The method of claim 1 further comprising the steps of:

annealing said refractive index grating at an elevated temperature; and

recoating at least said central portion of an optical fiber to protect said refractive index grating.

4. The method of claim 3 wherein said elevated temperature is approximately 300°

C.

5. The method of claim 3 wherein said recoating at least said central portion of an optical fiber includes application of a curable coating composition thereto using an ultrasonic spray head.

6. The method of claim 5 wherein said recoating at least said central portion of an optical fiber includes curing said curable coating composition.

7. The method of claim 3 wherein said recoating at least said central portion of an optical fiber includes application of a curable coating composition thereto using an ink jet printing/spray head.

8. The method of claim 7 wherein said recoating at least said central portion of an optical fiber includes curing said curable coating composition.

9. The method of claim 3 wherein said recoating at least said central portion of an optical fiber includes application of a curable coating composition thereto using an extrusion coating die.

10. The method of claim 9 wherein said recoating at least said central portion of an optical fiber includes curing said curable coating composition.

11. The method of claim 9 wherein said extrusion coating die is a split die having an open position and a closed position such that in said open position said split die receives an optical fiber and in said closed position said extrusion coating die surrounds an optical fiber to extrude said curable coating composition over said at least said central portion.

12. The method of claim 1 wherein removing said at least a buffer coating includes mechanical displacement of said at least a buffer coating from said central portion of an optical fiber.

13. The method of claim 12 wherein removing said at least a buffer coating further includes chemical displacement of said at least a buffer coating from said central portion of an optical fiber.

14. The method of claim 1 wherein removing said at least a buffer coating includes chemical displacement said at least a buffer coating from said central portion of an optical fiber.

15. The method of claim 1 further including the step of proof testing an optical fiber containing said optical fiber refractive index grating.