Claims
- 1. A method for fabricating a low-loss an optical fiber transmission line, comprising:
(a) splicing together at a splice point a first fiber having a doped core and at least one doped cladding region defining a first modefield diameter to a second fiber having a second modefield diameter larger than the first modefield diameter; (b) loading the spliced fibers into a heat treatment station; (c) heating a splice zone including the splice point according to a heating profile to cause a tapered expansion of the doped core, while causing a smooth diffusion of the doped cladding region, in order to reduce modefield mismatch between the first and second fibers.
- 2. The method of claim 1, wherein step (c) includes applying a controlled tension across the splice point as it is heated to the differential diffusion temperature.
- 3. The method of claim 1, wherein step (a) includes using a fusion splicer to splice together the first and second fibers.
- 4. The method of claim 1, wherein the first fiber is an inverse dispersion fiber.
- 5. The method of claim 4, wherein the first fiber is a dispersion compensating fiber.
- 6. The method of claim 4, wherein the core region is doped with germanium, and wherein the cladding region is doped with fluorine.
- 7. The method of claim 4, wherein the second fiber is a standard single mode fiber.
- 8. A method for determining differential diffusion parameters, comprising:
(a) splicing together at a splice point a first fiber having a doped core and at least one doped cladding region defining a first modefield diameter to a second fiber having a second modefield diameter larger than the first modefield diameter; (b) loading the spliced fibers into a heat treatment station; (c) applying heat from a heating source to a splice zone including the splice point, while monitoring the first fiber's refractive index profile, the refractive index profile including portions corresponding to the doped core and cladding regions of the first fiber; (d) adjusting the heat source until there is a visible movement in the cladding region refractive index profile and no visible movement in the core region refractive index profile; and (e) continuing to apply heat to the splice zone until there is no further visible movement in the cladding region refractive index profile.
- 9. The method of claim 8, wherein step (c) includes applying a controlled tension across the splice point, while applying heat to the splice point.
- 10. The method of claim 8, wherein the first fiber is an inverse dispersion fiber.
- 11. The method of claim 10, wherein the first fiber is a dispersion compensating fiber.
- 12. The method of claim 11, wherein the core dopant is germanium and the cladding dopant is fluorine.
- 13. The method of claim 10, wherein the second fiber is a standard single mode fiber.
- 14. A method for fabricating a low-loss optical transmission line:
(a) using a fusion splicer to splice together at a splice point a first fiber having a doped core and at least one doped cladding region defining a first modefield diameter to a second fiber having a second modefield diameter larger than the first modefield diameter; (b) using the fusion splicer to cause a thermal expansion of the first fiber's doped core, such that modefield mismatch between the first and second fibers is reduced; (c) loading the spliced fibers into a heat treatment station; and (d) heating a splice zone including the splice point according to a heating profile to cause a smooth diffusion of the first fiber's doped cladding region, while maintaining the first fiber's expanded core, thereby reducing splice loss.
- 14. The method of claim 13, wherein step (d) includes applying a controlled tension across the splice point, while applying heat to the splice point.
- 15. The method of claim 13, wherein the first fiber is an inverse dispersion fiber.
- 16. The method of claim 15, wherein the first fiber is a dispersion compensating fiber.
- 17. The method of claim 16, wherein the core region of the first fiber is doped with germanium, and wherein the cladding region of the first fiber is doped with fluorine.
- 18. The method of claim 15, wherein the second fiber is a standard single mode fiber.
RELATED APPLICATIONS
[0001] The present application is a continuation-in-part of U.S. patent application Ser. No. 09/778,444, filed on Feb. 7, 2001, assigned to the assignee of the present application, which is incorporated herein by reference in its entirety.
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
09778444 |
Feb 2001 |
US |
Child |
10197184 |
Jul 2002 |
US |