Comparison of dispersion compensation methods for 40Gbit/s WDM-PON transmission systems

The increasing number of end-users and growing demand for higher data rate affect fiber-optical transmission systems (FOTS), which need to catch up with the different performance requirements. Optical-fiber network still is the best solution for supporting high data rates and large distance coverage between network nodes. The most common destructive effect for FOTS is chromatic dispersion (CD) and the negative effect of CD FOTS increases with the increase of bitrate or optical fibers length. When one or both conditions are fulfilled the effect of chromatic dispersion must be taken into consideration but if it is ignored, dispersion can completely corrupt transmitted data because of intersymbol interference (ISI). In this paper authors demonstrate two dispersion compensation methods — dispersion compensation fiber (DCF) and fiber Bragg grating (FBG), for 16-channel 40Gbit/s per channel wavelength-division multiplexed C-band fiber-optical transmission systems with non-return-to-zero (NRZ) return-to-zero (RZ) line codes. The proposed passive optical network architecture with 40 Gbit/s transmission speed is fully in line with NG-PON2 architecture, according to ITU-T G.989.1 recommendation. Main goal of this paper is to find out which of the above mentioned dispersion compensation methods have the most positive effect on the reach of fiber-optical transmission line, when RZ or NRZ coding is used, depending on the dispersion compensation module's (DCM's) location in optical distribution network. Therefore, through simulations, authors investigated multiple channel 100 GHz spaced WDM transmission systems, where both DCF and FGB dispersion compensation methods are used.