Design of Dispersion Flattened and Compensating Fibers for Dispersion-Managed Optical Communications Systems

Single mode optical fibers having minimum non-zero dispersion over the spectral windows of 1300 and 1550 nm region are essential for the multi-channel operation of dense wavelength multiplexed systems and minimizing the nonlinear four wave mixing effects This paper demonstrates that nonzero dispersion flattening of the dispersion factor extends over a wavelength range of more than 350 nm is achievable. We present the design of the dispersion flattening of the non-zero dispersion fiber (NZ-DF) with minimum of dispersion factor, as well as dispersion compensating fiber (DCF) that allows complete dispersion compensation over entire Sto L-bands of the third communications window .The overall dispersionlength (DL) product of a fiber span can be tailored to be close to zero. Hence the designed composite fiber length of a “kappa” value of 1 with a DL product of zero for the span length of 100 Kms of the fiber is demonstrated. The effects of the geometrical and index distribution parameters of the triple-clad profile to sensitivity of the total dispersion factor of the DFF and DCF are analyzed. We also outline design guidelines for identifying the critical parameters and steps for tailoring the fiber dispersion property.