Multimode Optical Fibers and Methods of Manufacture Thereof

Abstract

The present invention generally relates to the field of fiber optics, and more specifically to optical fibers, methods of manufacturing optical fibers, and methods of classifying optical fibers. In an embodiment, the present invention is a multimode optical fiber which comprises a core and clad material system where the refractive indices of the core and cladding are selected to minimize chromatic dispersion in the 850 nm wavelength window and the refractive index profile is optimized for minimum modal-chromatic dispersion in channels utilizing VCSEL transceivers. Multimode optical fibers according to this embodiment may have increased channel bandwidth.

We claim: 
     
         1 . A method for manufacturing a multimode optical fiber that supports operation only within a single wavelength operating window, said method comprising the steps of:
 producing a core having a center and a refractive index profile optimized to operate within said single wavelength operating window, said step of producing a core includes adding a concentration of at least one core dopant to said core;   at least partially surrounding said core with a cladding, said cladding having a concentration of at least one cladding dopant added to said cladding; and   at least partially surrounding said cladding with a jacket,   wherein said at least one core dopant and said concentration of said at least one core dopant are selected to produce a refractive index n 0  at said center of said core and to reduce a zero dispersion wavelength of said core below 1295 nanometers (nm),   wherein said at least one cladding dopant and said concentration of said at least one cladding dopant are selected to produce a cladding with a refractive index n 1 , and   wherein said at least one core dopant, said concentration of said at least one core dopant, said at least one cladding dopant, and said concentration of said at least one cladding dopant are selected such that   
       
         
           
             
               
                 
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         2 . The method of  claim 1 , wherein said step of adding said concentration of said at least one core dopant to said core includes adding at least one of boron, oxygen, chlorine, phosphorus, and fluorine,
 and wherein said at least one cladding dopant includes fluorine.   
     
     
         3 . The method of  claim 1 , wherein said step of adding said concentration of said at least one core dopant to said core excludes adding germanium. 
     
     
         4 . A method for manufacturing a multimode optical fiber operable only within a single wavelength operating window, said method comprising the steps of:
 producing a core having a center and a refractive index profile optimized to operate within a single wavelength operating window, said step of producing a core includes adding a concentration of at least one core dopant to said core;   at least partially surrounding said core with a cladding, said cladding having a concentration of at least one cladding dopant added to said cladding; and   at least partially surrounding said cladding with a jacket,   wherein said at least one core dopant and said concentration of said at least one core dopant is selected to produce a refractive index n 0  at said center of said core and to reduce a magnitude of chromatic dispersion within said single wavelength operating window to less than 89 picoseconds per nanometer wavelength change and kilometer propagation distance (ps/nm-km),   wherein said at least one cladding dopant and said concentration of said at least one cladding dopant is selected to produce a cladding with a refractive index n 1 , and   wherein said at least one core dopant, said concentration of said at least one core dopant, said at least one cladding dopant, and said concentration of said at least one cladding dopant are selected such that   
       
         
           
             
               
                 
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         5 . A method for manufacturing a multimode optical fiber operable only within a single wavelength operating window, said method comprising the steps of:
 producing a core having a center and a refractive index profile optimized to operate within a single wavelength operating window, said step of producing a core includes adding a concentration of at least one core dopant to said core;   at least partially surrounding said core with a cladding, said cladding having a concentration of at least one cladding dopant added to said cladding; and   at least partially surrounding said cladding with a jacket,   wherein said at least one core dopant and said concentration of said at least one core dopant is selected to produce a refractive index n 0  at said center of said core, to reduce a magnitude of chromatic dispersion within said single wavelength operating window to less than 89 picoseconds per nanometer wavelength change and kilometer propagation distance (ps/nm-km), and to reduce a zero dispersion wavelength of said core below 1295 nanometers (nm),   wherein said at least one cladding dopant and said concentration of said at least one cladding dopant is selected to produce a cladding with a refractive index n 1 , and   wherein said at least one core dopant, said concentration of said at least one core dopant, said at least one cladding dopant, and said concentration of said at least one cladding dopant are selected such that   
       
         
           
             
               
                 
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