Patent ID: 8380019

Claim:
A tunable dispersion compensator, comprising: at least one tunable chirped fiber Bragg grating and a pathway thereto coupled into an optical system, the grating providing a tunable amount of dispersion, D, to compensate for dispersion in a transmission carried by the system, the grating introducing a differential group delay, DGD (FBG) , into the system that varies as a function of D, and a differential group delay element connected into the pathway to the grating, the differential group delay element introducing into the system a fixed offsetting differential group delay, DGD (bias) , whereby the total combined differential group delay, DGD (total) , introduced by the grating and the differential group delay element is equal to the sum of and DGD (FBG) ,and DGD (bias) , wherein, for at least one tuning value of the grating, DGD (bais) and DGD (FBG) are oppositely signed and have absolute, non-zero values that are substantially equal to each other whereby at the tuning value, DGD (total) is substantially equal to zero.