In this Book, Performance analysis has been carried out by examining FBG induced Crosstalk and BER by varying the Bandwidth, Number of channels presence and Channel separation. It is found that when the Bandwidth is increased, Crosstalk is also increases.If the Channel separation is increased then SCR is also increases. In another consideration, if one channel is drop then the crosstalk is decreases for the desired channel. However, there is no such effects for 16 and 32 channels WDM system with 15 and 31 interfering channels respectively. Overall work has been done by Numerical Simulation using MATLAB.