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US 5,999,679 AGranted
Dispersion compensating single mode waveguide
AssigneeCorning Incorporated
InventorsA. Joseph Antos, George E. Berkey, Daniel W. Hawtof, G. Thomas Holmes, Yanming Liu
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Abstract
A dispersion compensating single mode optical waveguide fiber designed to change the wavelength window of operation of a link from 1301 nm to 1550 nm. The dispersion compensating waveguide fiber is characterized by a core glass region refractive index profile comprised of at least three segments. The segment on the waveguide center has a positive relative refractive index. At least one segment spaced apart from the waveguide centerline has a negative refractive index.
Claims19
A single mode optical waveguide fiber, comprising:
- a core glass region, disposed about the long axis centerline of the waveguide fiber, comprising at least three segments, each having a refractive index profile, the first segment positioned to include the waveguide centerline, and having a radius, r.sub.1, extending from the centerline to the point of said first segment located farthest from the centerline, and, a relative refractive index percent, .DELTA..sub.1 %, and additional segments, adjacent one another, extending radially outward from said first segment, having respective radii, r.sub.1, extending from the centerline to the point of said with segment located farthest from the centerline, and, relative refractive index percent, .DELTA..sub.i %, i =2 to n, wherein n is the number of said segments,
- said first segment symmetrically positioned about the long axis of the optical waveguide fiber, wherein .DELTA..sub.1 % is positive, and,
- at least one segment having a .DELTA..sub.i % which is negative;
- and,
- a clad glass layer surrounding said core glass region having a refractive index, n.sub.c, which is less that the refractive index of at least a part of said core glass region;
- wherein, the respective radii, r.sub.1, and r.sub.i, and relative refractive index percents, .DELTA..sub.1 % and .DELTA..sub.i % are chosen to provide a pre-selected negative total dispersion at 1550 nm no greater than about -150 ps/nm-km.
3 more elements
A single mode optical waveguide fiber link comprising:
- a first length of single mode waveguide fiber, L.sub.smf, having a cut off wavelength less than 1310 nm, a zero dispersion wavelength in the range 1280 nm to 1350 nm, and a total dispersion at 1550 nm, D.sub.smf ;
- and,
- a second length of single mode waveguide, L.sub.dc, having a total dispersion D.sub.d and an attenuation coefficient .alpha. dB/km;
- wherein the algebraic sum of the products L.sub.smf .times.D.sub.smf and L.sub.dc .times.D.sub.d is equal to a pre-selected value, and, the ratio D.sub.d /.alpha. and A.sub.eff are selected to provide a non-linear discrimination factor, G.sub.nl, for the waveguide fiber link, which is no greater than the non-linear discrimination factor for said first single mode fiber length, L.sub.smf.
1 more element
A method of making a dispersion compensating single mode optical waveguide fiber comprising the steps:
- forming a draw preform having a core glass region and a surrounding cladding layer, wherein, said core glass region is disposed about the long axis centerline of the waveguide fiber, comprising at least three segments, each having a refractive index profile, the first segment positioned to include the waveguide centerline, and having a radius, r.sub.1, extending from the centerline to the point of said first segment located farthest from the centerline, and, a relative refractive index percent, .DELTA..sub.1 %, and additional segments, adjacent one another, extending radially outward from said first segment, having respective radii, r.sub.i, extending from the centerline to the point of said with segment located farthest from the centerline, and, relative refractive index percent, .DELTA..sub.i %, i=2 to n, wherein n is the number of said segments,
- said first segment symmetrically positioned about the long axis of the optical waveguide fiber, wherein .DELTA..sub.1 % is positive, and,
- at least one segment having a .DELTA..sub.i % which is negative;
- and,
- a clad glass layer surrounding said core glass region having a refractive index, n.sub.c, which is less than the refractive index of at least a part of said core glass region;
- wherein, the respective radii, r.sub.1, and r.sub.i, and relative refractive index percents, .DELTA..sub.1 % and .DELTA..sub.i %, are chosen to provide a pre-selected negative total dispersion at 1550 nm no greater than about -150 ps/nm-km;
- drawing said preform into a waveguide fiber having a pre-selected outside diameter, wherein said drawing tension is no less than about 100 grams;
- coating said waveguide fiber with at least one layer of polymer material;
- and,
- heat treating said coated waveguide fiber to essentially remove residual stress in the coating.
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Dependencies are inferred from the claim text.