Design of Tb/s capacity Quadruply Cladded Optical Fiber for WDM Systems

摘要

The enormous transmission capacity of the order of thousand of Gb/s offered by single mode fibers cannot be fully utilized with the conventional step index fiber, However for these designs and the new ones to come a numerical technique , which is fast and accurate, is required for calculating the dispersion Most of the existing numerical approaches are good enough for the calculation of propagation constant only, though some of them are not suited for arbitrary refractive index profile, A powerful numerical technique, the quadratic finite element method [FEM] is used for analyzing the modal characteristic of single mode optical fiber with arbitrary refractive index profile, The simulated results when compared with earlier reported ones for step index profile, confirms the accuracy of the proposed numerical technique, It is shown that multiple cladded fiber is better suited for Wideband Systems. Dispersion flattened fibers have been proposed in the past with W - profile, but all such fiber designs have been observed to be bend sensitive in the long wavelength window, as one has to operate very close to the cutoff of the fundamental mode. A generalized refractive index profile has been used here, which is capable of generaing a variety of earlier proposed profile. Computation shows that by properly optimizing the profile parameters, a wideband fiber can be designed where the dispersion can be kept confined with in ± 1,0 ps/ km - nm over a wide entire wavelength span from 1280 to 1550 nm ( 370 nm). The proposed fiber consists of Quadruply Cladded (QC) Profile and is capable of transmitting high speed data ( > 1 Tb/s). The proposed design is expected to be relatively insensitive to bending losses , as the field even at longer wavelength (1550 nm ) is well guided within the QC fiber structure. The wavelength span includes both the low loss transmission window near 1310 & 15.50 nm, The results suggest an excellent wideband optical waveguide for future WDM systems.