Nonlinear equalizers based on nonlinear Volterra theory and maximum-likelihood sequence estimators (MLSE) are
investigated to mitigate the nonlinear distortions resulting from the incomplete sideband suppression in optical single
side band modulation (OSSB) systems. Through theoretical analysis and simulations, we demonstrate that electrical
dispersion compensation (EDC) by using these nonlinear equalizers can achieve better performance compared to
conventional analog equalizers including feedforward equalizers (FFE) and decision feedback equalizers (DFE).
Multilevel intensity modulation such as 4-ASK signalling can reduce the bandwidth requirement in multimode fiber (MMF) links. However, 4-ASK signalling is susceptible to the laser nonlinearity. In addition, even with 4-ASK signalling, the maximum transmission distance over installed MMF is still limited by differential mode delay (DMD) to less than 300m for 10GE. We propose and demonstrate that directly modulated laser nonlinearity and modal dispersion resulting from DMD can be eliminated simultaneously by using a nonlinear electrical equalizer for 4-ASK signalling in high-speed MMF short links.
We present both optical and electrical compensation of Differential Mode Delay (DMD) in Multimode Fiber (MMF) links. Based on the rigorous analysis of optical compensation of DMD, a new kind of Dispersion Compensating Fiber (DCF) is proposed. We show that 10Gb/s Ethernet reach for conventional MMF can be extended to 300m by splicing 10~35m of this DCF. We prove that ISI resulting from DMD can be mitigated with electrical compensation by using linear or nonlinear equalizers. Moreover, we demonstrate that combination of optical and electrical compensation can dramatically enhance the bandwidth of installed MMF. Simulations carried out on six types of typical installed MMF for Overfilled Launch (OFL) as well as Restricted Mode Launch (RML) condition exhibit that transmission distance for conventional MMF with bandwidth-distance product 500MHz-km can be extended to 1000m or beyond with 2dB Eye-Opening Penalty (EOP).
One of the key technologies of the application of POF in the LAN is the coupling of the source and the POF as well as between the POF. In this article, main and important properties, which have great influences on the coupling efficiency of POF, are studied and discussed in detail.