Optimization of all-optical network testbed regarding NRZ and RZ modulation

The non-return-to-zero (NRZ) and return-to-zero (RZ) formats are two well-known cost-effective candidates for the optimum modulation in all-optical networks (AON). This paper focuses on the effects of novel active/passive optical devices, such as photonic switches and erbium doped fibre amplifiers (EDFA), and the effects of modulation formats on the overall system performance, under metropolitan environments without dispersion control/compensation. The overall system performance of an AON metropolitan WDM testbed is investigated by numerical simulation while using NRZ and RZ modulation respectively. Q factor (equivalent to bit error ratio) is selected as the criterion for the comparison. The testbed is based on commercially available photonic switches, which support dynamic wavelength switching. The testbed operates at 10 Gbit/s per channel. The effects of transmitter optical powers and the extinction ratios are numerically analyzed. Based on these results the system parameters, such as transmitter power and extinction ratio are optimized for the AON testbed.