Study of performance degradation introduced by Add/Drop multiplexing operation in a SOA-based WDM Ring network

In the present work we have investigated the performance degradation in a semiconductor optical amplifier (SOA) based multi span WDM ring network during add/drop multiplexing operation under steady state and dynamic condition. The simulation is performed for analysis of the worst case scenario, where seven out of eight wavelength division multiplexed (WDM) channels are added/dropped in an add/drop multiplexer (ADM). It is seen from the simulation that the detrimental transient behaviour in SOA, due to add/drop operation, severely limits the number of cascaded stages in the ring. Transient plot of bit error rate (BER) shows a maximum degradation to 10^-5 only after four cascaded stages, which is much severe than the steady state value of 10^-8 even after eight stages of cascading. Study of other impairments along with their implications have also been included in this paper.