Application Analysis Of Dispersion Compensation Based On FBG On Next Generation NZ-DSF Fibers

Recently, next-generation non-zero dispersion-shifted fibers (e.g. Large effective area fiber - LEAF) is widely applied in wavelength division multiplexing(WDM) systems, especially in dense WDM systems. Because it has a lower dispersion and higher threshold of non-linear effects in compare with standard single-mode fibers. However, this fibers also has a significantly higher relative dispersion slope, which increases the difficulty of dispersion management.This article analyses the properties of next-generation non-zero dispersion-shifted fibers, and demonstrates a design of dispersion and dispersion slope compensator for LEAF fiber in WDM systems. It can compensate dispersion and dispersion slope separately by combining a broadband non-channelized linear chirped fiber Bragg grating (CFBG) and a pair of nonlinear CFBGs, which be inversely cascaded in a four-port optical circulator. Advantages of this design over competing technologies include simple configuration, big bandwidth, optimal dispersion matching, easy fabricate and potentially low cost. A numerical experiment of compensating a 50-km-long LEAF fiber in WDM system prove the feasibility of this design.The apodization technique of FBG is another topic of this article. According to the requirement of this compensator, we design a novel apodization approach: it apodize a FBG, which has a biger bandwidth than system's demand, to system's bandwidth. A appropriate proportion of apodization factor can restrain ripple of time delay effectively. Finally, a experiment of reducing time delay ripple of the compensator is discussed.