USRE37680EExpiredUtilityPatentIndex 52

Dispersion shifted optical waveguide fiber

Assignee: CORNING INCPriority: Oct 17, 1994Filed: Mar 17, 1999Granted: Apr 30, 2002

Est. expiryOct 17, 2014(expired)· nominal 20-yr term from priority

Inventors:BHAGAVATULA VENKATA A

G02B 6/0286G02B 6/02285G02B 6/03688G02B 6/02238G02B 6/03622G02B 6/03644G02B 6/03611G02B 6/03666

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Abstract

A single mode optical waveguide fiber designed for high data rate, or WDM systems or systems incorporating optical amplifiers. The optical waveguide has a compound core having a central region and at least one annular region surrounding the central region. A distinguishing feature of the waveguide core is that the minimum refractive index of the central core region is less than the minimum index of the adjacent annular region. A relatively simple profile design has the characteristics of ease in manufacturing together with, flexibility in tailoring D w to yield a preselected zero dispersion wavelength, dispersion magnitude over a target wavelength range, and dispersion slope. The simplicity of profile gives reduced polarization mode dispersion.

Claims

exact text as granted — not AI-modified

I claim:

1. A single mode optical waveguide fiber comprising:
a core region comprising,
a central region having a radius a 0 and a minimum refractive index n 0 ,
at least one annular region surrounding said central region, wherein the innermost of said at least one annular region is adjacent said central region and has inner radius a i and minimum refractive index n i , and a i &gt;a 0 and n i &gt;n 0 ; and,
a clad layer adjacent said core region having refractive index n c and n c &lt;n i .

2. The single mode optical waveguide of claim 1 wherein the respective refractive indices of said central region and said at least one annular region vary along the radius of said core.

3. The single mode optical waveguide of claim 2 wherein the respective refractive indices of said central region and said at least one annular region of said core are cylindrically symmetrical.

4. The single mode optical waveguide fiber of claim 1 wherein said central core region is surrounded by one adjacent annular region.

5. The single mode optical waveguide fiber of claim 4 wherein said one annular region has a substantially constant refractive index.

6. The single mode optical waveguide fiber of claim 5 wherein said central region has a substantially constant refractive index.

7. The single mode optical waveguide fiber of claim 6 wherein n 0 is substantially equal to n c .

8. The single mode waveguide fiber of claim 1 further including at least one annular region in said clad layer having a refractive index less than n c .

9. The single mode waveguide fiber of claim 1 further including at least one annular region in said central core region having a refractive index less than n c .

10. The single mode optical waveguide fiber of claim 1 wherein said central core region is surrounded by a first and a second annular region, wherein said first annular region is adjacent said central region and said second annular region is adjacent said first annular region.

11. The single mode optical waveguide of claim 10 wherein said respective first and second annular regions have minimum refractive indices n 1 and n 2 , and n 1 &gt;n 0 and n 2 &gt;n 0 .

12. The single mode optical fiber of claim 1 wherein the index of refraction of the central region is greater than the clad layer and is equal to or less than about 11% of the index of retraction of said at least one annular region surrounding the central region.

13. A single mode optical waveguide fiber comprising:
a core region comprising,
a central region having a radius a 0 of substantially constant refractive index n 0 ,
at least one annular region having a radius a 1 surrounding said central region, the innermost annular region is adjacent said central region and has minimum refractive index n i and n i &gt;n 0 ;
a clad layer surrounding said core region having refractive index n c ;
characterized in that the ratio a 0 /a 1 is in the range of 0.55 to 0.75 and the total dispersion slope is less than about 0.075 ps/nm 2 -km.

14. The single mode optical waveguide fiber of claim 13 characterized in that core radius is in the range of about 3.5 to 3.9 microns and the zero dispersion wavelength is substantially constant for about 5% variations from target of core radius or cut off wavelength.

15. The single mode optical waveguide fiber of claim 13 characterized in that the core radius is greater than about 3.4 microns and the zero dispersion wavelength is outside the range of about 1530 nm to 1565 nm.

16. The single mode optical waveguide fiber of claim 13 characterized in that the core radius is between 3.4 and 3.5 microns and the zero dispersion wavelength is in the range of about 1500 nm to 1530 nm.

17. A single mode optical waveguide fiber comprising:
a core region comprising
an axially symmetric central region having minimum refractive index n 0 ,
an axially symmetric annular region adjacent said central region, having minimum refractive index n 1 , inner radius a i , and outer radius a o , wherein n 1 &gt;n 0 and
the ratio a i /a o is in the range 0.35 to 0.80, and;
a clad layer surrounding said core having refractive index n c and n 1 &gt;n c .

18. The single mode fiber of claim 17 wherein the ratio a i /a o is about 0.50.

19. The single mode optical waveguide fiber of claim 17 wherein n 0 is substantially constant.

20. The single mode optical waveguide fiber of claim 19 wherein n 0 is substantially equal to n c .

21. The single mode optical waveguide fiber of claim 20 wherein n 1 is substantially constant.

22. The single mode optical waveguide fiber of claim 21 wherein n 1 is in the range of about 1.4700 to 1.4800.

23. A single mode optical waveguide fiber comprising:

a core region comprising,

a central region having a radius a 0 and of substantially constant refractive index n 0 ,
at least one annular region having a radius a i and surrounding said central region, the innermost annular region is adjacent said central region and has minimum refractive index n i and n i &gt;n 0 ;
a clad layer surrounding said core region having refractive index n c ;
wherein the ratio a 0 /a i is one selected from the group consisting of ( a ) a range of 0 . 35 to 0 . 45 , ( b ) a range of 0 . 45 to 0 . 55 , and ( c ) a ratio in the range of about 0 . 55 to 0 . 75 ; and

wherein the core radius is in a range of about 3 . 0 to 3 . 9 microns and the zero dispersion wavelength is in a range of about 1570 nm to 1455 nm.

24. A single mode optical waveguide fiber comprising:

a core region comprising,

25. A single mode optical waveguide fiber comprising:

a core region comprising,

a central region having a radius a 0 and of substantially constant refractive index n 0 ,
at least one annular region having a radius a i and surrounding said central region, the innermost annular region is adjacent said central region and has minimum refractive index n i and n i &gt;n 0 ;
a clad layer surrounding said core region having refractive index n 0 ;
wherein the ratio a 0 /a i is one selected from the group consisting of ( a ) a range of 0 . 35 to 0 . 45 , ( b ) a range of 0 . 45 to 0 . 55 , and ( c ) a ratio in the range of about 0 . 55 to 0 . 75 ; and
wherein the total dispersion between 1520 and 1600 nm is in a range of from about 0 . 5 to 4 ps/nm - km.

26. A single mode optical waveguide fiber comprising:

a core region comprising,

27. A single mode optical waveguide fiber comprising:

a core region comprising,

wherein the core radius is greater than about 3 . 4 microns and the zero dispersion wavelength is outside the range of about 1530 nm to 1565 nm.

28. A single mode optical waveguide fiber comprising:

a core region comprising,

wherein the core radius is between 3 . 4 and 3 . 5 microns and the zero dispersion wavelength is in the range of about 1500 nm to 1530 nm.

29. The single mode fiber of claim 17 , wherein minimum refractive indices n 1 and n 0 and radii a i and a 0 are selected to provide a dispersion slope which is less than 0 . 075 ps/nm 2 - km.

30. The single mode optical fiber of claim 17 , wherein the zero dispersion wavelength is outside the wavelength range of about 1530 to 1565 nm.

31. The single mode optical fiber of claim 29 , wherein the zero dispersion wavelength is outside the wavelength range of about 1530 to 1565 nm.

32. The single mode optical waveguide fiber of claim 17 , wherein the radii and refractive index profiles of the central region and annular region are selected to provide a total dispersion which is in the range of about 0 . 5 to 4 ps/nm- km over the wavelength range from about 1520 to 1600 .

33. The single mode fiber of claim 29 , wherein the mode field diameter of said fiber is greater than or equal to about 8 microns.

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