Improving the effect of ISI from optical Communication System by Using Equalizers

The technique of compensating the effect of ISI in optical communication system described here is equalization .This technique of equalization is used for compensating the effect of ISI in the channel which causes disturbance in the signal, which is transmitted. There are various types of equalizers are used depending upon the application used and the kind of system in which it is used. The most important purpose of the equalization technique is to correct the channel frequency response. They not only correct the frequency response of the channel but also cancel the effects of multipath signal component present in the system. This paper aims at studying and simulation of equalization techniques; here two types of equalization techniques are stimulated, they are Zero Forcing Equalization and MMSE Equalization. Here in these techniques filters are used at the receiving end to cancel the effects of ISI in the received signal introduced by channel impulse response. As Inter Symbol Interference is considered to be one of the most challenging problems encountered in fiber optical communication system so as to remove the effect we can apply equalizer at the receiver to undo the effect of the channel by applying an inverse filter. The First technique used is zero forcing (ZF) equalizer to reduce the effect of inter symbol interference (ISI) introduced by the channel impulse response. The second method used Minimum Mean Square Error (MMSE) equalizer to reduce the effect of inter symbol interference (ISI) introduced by the channel impulse response. Simulation result shows that the Minimum Mean Square Error (MMSE) equalizer reduce the effect of inter symbol interference (ISI) better as compare to that of zero forcing (ZF) equalizer.