Microstructured optical fibers and methods

• US 8,464,556 B2
• Filed: 05/05/2008
• Issued: 06/18/2013
• Est. Priority Date: 05/08/2007
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Bookbinder, Dana Craig, Desorcie, Robert Brett, McDermott, Mark Alan, Tandon, Pushkar
• Primary Examiner(s): DEHGHAN, QUEENIE S
• Application Number:
  US12/151,170
• Publication Number:
  US 20080276650A1
• Time in Patent Office: 1,870 Days
• Field of Search: 654/27, 654/21, 654/17, 654/13
• US Class Current: 65/421
• CPC Class Codes: C03B 2203/14 Non-solid, i.e. hollow products, e.g. hollow clad or with core-clad interface
• CPC Class Codes: C03B 2203/42 Photonic crystal fibres, e.g. fibres using the photonic bandgap PBG effect, microstructured or holey optical fibres
• CPC Class Codes: C03B 2205/44 Monotoring or regulating the preform feed rate
• CPC Class Codes: C03B 2205/72 Controlling or measuring the draw furnace temperature
• CPC Class Codes: C03B 37/0142 Reactant deposition burners
• CPC Class Codes: C03B 37/01446 Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering C03B37/01853 takes precedence
• CPC Class Codes: C03B 37/0146 Furnaces therefor, e.g. muffle tubes, furnace linings
• CPC Class Codes: C03B 37/01466 Means for changing or stabilising the diameter or form of tubes or rods C03B37/01861 takes precedence
• CPC Class Codes: C03B 37/02781 Hollow fibres, e.g. holey fibres

Abstract

Method of making a microstructured optical fiber. Silica glass based soot is deposited on a substrate to form at least a portion of an optical fiber preform by traversing a soot deposition burner with respect to said substrate at a burner traverse rate greater than 3 cm/sec, thereby depositing a layer of soot having a thickness less than 20 microns for each of a plurality of burner passes. At least a portion of the soot preform is then consolidated inside a furnace to remove greater than 50 percent of the air trapped in said soot preform, said consolidating taking place in a gaseous atmosphere containing krypton, nitrogen, or mixtures thereof under conditions which are effective to trap a portion of said gaseous atmosphere in said preform during said consolidation step, thereby forming a consolidated preform which when viewed in cross section will exhibit at least 50 voids therein.

Claims

1. A method of making an optical fiber comprising depositing silica glass based soot on a substrate to form at least a portion of an optical fiber preform by traversing a soot deposition burner with respect to said substrate at a burner traverse rate greater than 3 cm/sec, thereby depositing a layer of soot having a thickness less than 20 microns for each of a plurality of burner passes;

and consolidating said at least a portion of the soot preform inside a furnace to remove greater than 50 percent of the air trapped in said soot preform, said consolidating taking place in a gaseous atmosphere containing krypton, argon, SO₂, or mixtures thereof under conditions which are effective to trap a portion of said gaseous atmosphere in said preform during said consolidation step, thereby forming a consolidated preform which when viewed in cross section will exhibit at least 50 voids therein.

2. The method of claim 1, wherein said preform when viewed in cross section will exhibit at least 10,000 voids therein.

3. The method of claim 1, wherein said consolidating taking place in a gaseous atmosphere further comprising helium.

4. The method of claim 1, wherein said consolidating taking place in a gaseous atmosphere which comprises krypton.

5. The method of claim 1, wherein said soot deposited in said depositing step comprises a portion of the cladding region of the optical fiber preform.

6. The method of claim 1, wherein said burner traverse rate in said depositing step is greater than 7 cm/sec.

7. The method of claim 6, wherein said depositing step comprises depositing a layer of soot having a thickness less than 10 microns for each of a plurality of burner passes.

8. The method of claim 6, wherein said depositing step comprises depositing a layer of soot having a thickness less than 15 microns for each of a plurality of burner passes.

9. The method of claim 1, wherein said burner traverse rate in said depositing step is greater than 10 cm/sec.

10. The method of claim 1, wherein said depositing step comprises depositing a layer of soot having a thickness less than 15 microns for each of a plurality of burner passes.

11. The method of claim 1, further comprising, subsequent to said consolidation step and prior to a step of drawing the preform into an optical fiber, drawing the consolidated preform having voids therein into a cane to thereby reduce the diameter of the consolidated preform having voids therein to a outer preform diameter which is greater than 5 mm, under conditions which are effective to cause said voids to expand in diameter during the redraw step.

12. The method of claim 11, wherein said drawing the preform into cane step comprises drawing said preform at a speed of greater than 5 cm per minute while exposing the preform to a temperature between about 1650-1775°

C.

13. The method of claim 11, wherein said drawing the preform into cane step comprises drawing said preform at a speed of greater than 7 cm per minute while exposing the preform to a temperature between about 1650-1775°

C.

14. The method of claim 11, further comprising drawing said fiber at a draw tension between 250 and 300 grams.

15. The method of claim 1, further comprising drawing said fiber at a draw tension greater than 200 g.

16. The method of claim 1, further comprising drawing said fiber at a draw tension between 250 and 300 grams.