Chromatic dispersion compensation system and method

Abstract

Dispersion compensation is provided in an optical transmission system. An optical line couples first and second transceivers, and a plurality of amplifiers coupled to the optical line are spaced throughout the optical line with variable span distances. A plurality of dispersion compensation modules include a coarse granularity fiber, a connector, and a fine granularity fiber. A memory is associated with the dispersion compensators to provide information related to the value of the dispersion compensation.

1 . A device, comprising: 
 a coarse granularity module;    a connector coupled to the coarse granularity module; and    a fine granularity module coupled to the connector;    wherein the coarse granularity module and the fine granularity module are capable of correcting dispersion of an optical signal.    
     
     
         2 . A device as recited in  claim 1  wherein the coarse granularity module has a resolution of at least 5 km.  
     
     
         3 . A device as recited in  claim 1  wherein the fine granularity module has a resolution of at least 1 km.  
     
     
         4 . A device as recited in  claim 1  wherein the device is coupled to an in-line amplifier.  
     
     
         5 . A device as recited in  claim 1  wherein the coarse granularity module and the fine granularity module are capable of being interconnected upon deployment in the field.  
     
     
         6 . A device as recited in  claim 1  wherein the coarse granularity module and the fine granularity module are capable of being interconnected prior to deployment in the field.  
     
     
         7 . A device as recited in  claim 1  wherein the coarse granularity module comprises a dispersion compensating fiber.  
     
     
         8 . A device as recited in  claim 1  wherein the coarse granularity module comprises a higher order mode device.  
     
     
         9 . A device as recited in  claim 1  wherein the coarse granularity module comprises a chirped fiber Bragg grating.  
     
     
         10 . A device as recited in  claim 1  wherein the coarse granularity module is capable of compensating for a dispersion slope of an optical fiber.  
     
     
         11 . A device as recited in  claim 1 , further comprising a first memory device coupled to the coarse granularity module.  
     
     
         12 . A device as recited in  claim 11 , further comprising a second memory device coupled to the fine granularity.  
     
     
         13 . A device as recited in  claim 12  wherein the first and second memory devices are capable of being electronically read.  
     
     
         14 . A device as recited in  claim 1  wherein the coarse granularity module is configured to overcompensate the dispersion of an optical signal.  
     
     
         15 . A device as recited in  claim 14  wherein the fine granularity module is configured to compensate for the overcompensation of the coarse granularity module.  
     
     
         16 . A device as recited in  claim 1  wherein the fine granularity module comprises a standard single mode fiber.  
     
     
         17 . A device as recited in  claim 1  wherein the fine granularity module comprises a non-zero dispersion shifted fiber.  
     
     
         18 . A device as recited in  claim 1  wherein the fine granularity module comprises a silica-core fiber.  
     
     
         19 . A device as recited in  claim 1  wherein the coarse granularity module has a resolution of at least 10 km.  
     
     
         20 . A device as recited in  claim 1  wherein the fine granularity module has a negative resolution.  
     
     
         21 . A device as recited in  claim 1 , further comprising a first memory device coupled to the coarse granularity module and a second memory device coupled to the fine granularity; and wherein the coarse granularity module is configured to overcompensate the dispersion of an optical signal, and the fine granularity module is configured to compensate for the overcompensation of the coarse granularity module.  
     
     
         22 . An optical transmission system, comprising: 
 a first transceiver capable of generating an optical signal;    an optical line coupled to the first transceiver;    a second transceiver coupled to the optical line and capable of receiving the optical signal;    a plurality of amplifiers coupled to the optical line, wherein the amplifiers are spaced throughout the optical line forming span distances, wherein the amplifiers are capable of amplifying the optical signal and wherein the span distances are variable;    a plurality of dispersion compensations modules (DCMs) coupled to the plurality of amplifiers;    wherein at least one of said DCMs comprises a coarse granularity module, a connector coupled to the coarse granularity module, and a fine granularity module coupled to the connector.    
     
     
         23 . A system as recited in  claim 22 , wherein the coarse granularity module has a resolution of at least 5 km.  
     
     
         24 . A system as recited in  claim 22 , wherein the fine granularity module has a resolution of at least 1 km.  
     
     
         25 . A system as recited in  claim 22 , wherein the at least one DCM is operatively coupled to one of said amplifiers.  
     
     
         26 . A system as recited in  claim 22 , wherein the coarse granularity module and the fine granularity module are capable of being interconnected upon deployment in the field.  
     
     
         27 . A system as recited in  claim 22 , wherein the coarse granularity module and the fine granularity module are capable of being interconnected prior to deployment in the field.  
     
     
         28 . A system as recited in  claim 22 , wherein the coarse granularity module comprises a dispersion compensating fiber.  
     
     
         29 . A system as recited in  claim 22 , wherein the coarse granularity module comprises a higher order mode device.  
     
     
         30 . A system as recited in  claim 22 , wherein the coarse granularity module comprises a chirped fiber Bragg grating.  
     
     
         31 . A system as recited in  claim 22 , wherein the coarse granularity module is configured to compensate for a dispersion slope of an optical fiber.  
     
     
         32 . A system as recited in  claim 22 , further comprising a first memory device coupled to the coarse granularity module.  
     
     
         33 . A system as recited in  claim 32 , further comprising a second memory device coupled to the fine granularity.  
     
     
         34 . A system as recited in  claim 33  wherein the first and second memory devices are capable of being electronically read.  
     
     
         35 . A system as recited in  claim 22 , wherein the coarse granularity module is configured to overcompensate the dispersion of an optical signal.  
     
     
         36 . A system as recited in  claim 35  wherein the fine granularity module is configured to compensate for the overcompensation of the coarse granularity module.  
     
     
         37 . A system as recited in  claim 22 , wherein the fine granularity module comprises a standard single mode fiber.  
     
     
         38 . A system as recited in  claim 22 , wherein the fine granularity module comprises a non-zero dispersion shifted fiber.  
     
     
         39 . A system as recited in  claim 22 , wherein the fine granularity module comprises a silica-core fiber.  
     
     
         40 . A system as recited in  claim 22 , wherein the coarse granularity module has a resolution of at least 10 km.  
     
     
         41 . A system as recited in  claim 22 , wherein the fine granularity module has a negative resolution.  
     
     
         42 . A system as recited in  claim 22 , further comprising a first memory device coupled to the coarse granularity module and a second memory device coupled to the fine granularity; and wherein the coarse granularity module is configured to overcompensate the dispersion of an optical signal, and the fine granularity module is configured to compensate for the overcompensation of the coarse granularity module.  
     
     
         43 . A system as recited in  claim 22 , further comprising: 
 a supervisory channel coupled to the plurality of amplifiers;    a plurality of controllers resident in at least a portion of the plurality of in-line amplifiers, each controller coupled to the supervisory channel; and    wherein the at least one DCM further comprises a first memory device coupled to the coarse granularity module and a second memory device coupled to the fine granularity module.    
     
     
         44 . A system as recited in  claim 42 , wherein the first and second memory devices are capable of storing identifiers.  
     
     
         45 . A system as recited in  claim 43 , wherein the first and second memory devices are capable of storing identifiers.  
     
     
         46 . A method, comprising: 
 identifying the location of a plurality of amplifiers in an optical transmission system;    identifying a plurality of variable span distances, wherein the variable span distances are calculated as the distance between amplifiers;    determining dispersion values associated with the variable span distances;    identifying coarse and fine granularity modules;    interconnecting the identified coarse and fine granularity modules with at least one connector to form at least one dispersion compensation module; and    using the at least one dispersion compensation module to compensate for dispersion of at least one variable span distance.    
     
     
         47 . A method as recited in  claim 46  wherein the determining of dispersion values comprises: 
 identifying the fiber type of the optical line spanning the variable span distance; and calculating a dispersion value based upon the fiber type and the length of the variable span distance.    
     
     
         48 . A computer program on a machine readable medium for identifying the location of a plurality of amplifiers in an optical transmission system which identifies coarse and fine granularity modules needed to form at least one dispersion compensation module which is used to compensate for dispersion of at least one variable span distance, said computer program comprising: 
 computer executable instructions for identifying the location of a plurality of amplifiers in an optical transmission system;    computer executable instructions for identifying a plurality of variable span distances wherein the variable span distances are calculated between amplifiers;    computer executable instructions for determining dispersion values associated with said variable span distances; and    computer executable instructions for identifying the coarse and fine granularity modules which are to be interconnected.