Optical Modulation and Dispersion Compensation Techniques for Ultra-High-Capacity TDM/WDM Transmission Systems

Abstract

To realize ultra-high-capacity optical transmission systems, the combination of faster TDM and denser WDM is essential, and it is important to select an optical modulation scheme suitable to fiber type, transmission distance, and total capacity. We compared the dispersion tolerance at 40 Gbit/s for the optical duobinary, NRZ, and RZ modulation schemes. In transmission systems with a relatively small fiber launched power where the SPM GVD effect is small, the optical duobinary scheme with large dispersion tolerance has a significant advantage. On the other hand, in a transmission system with large SPM-GVD effect, precise dispersion compensation is essential for any optical modulation scheme. Using strict dispersion compensation at every in-line repeater for each channel and out-band FEC, 40 Gbit/s×16 channel (200 GHz spacing) NRZ signals can be transmitted over 600 km NZ-DSF. We introduced our 40 Gbit/s automatic dispersion compensation experiment using a tunable laser and discussed dispersion slope compensation.KeywordsModulation SchemeTransmission DistanceChromatic DispersionSignal WavelengthDispersion CompensationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.