Reparation of chromatic dispersion using dispersion compensation bank and bit-error rate analysis at various power levels in 40 Gbps fiber optics system

Chromatic dispersion also called group velocity dispersion (GVD), is a very serious issue for communication engineers to design a wavelength division multiplexing (WDM) system. The pulse gets broader with increasing length of fiber due to chromatic dispersion and this pulse broadening effect stimulates the adjacent bit periods to overlap which causes inter symbol interference (ISI). The chromatic dispersion also has inverse relation with Four wave mixing (FWM) and Four wave mixing is minimum when chromatic dispersion is at highest level. The pulse broadening is a function of length of the fiber which has been shown in this work through simulation results for 40 Gbps fiber optics system at various lengths (50-200 km) using standard single mode fiber (SMF) in Optisystem software. In this work, DCB (dispersion compensation bank) has been used to reduce the effect of chromatic dispersion and it has been shown that the dispersion effect get mitigates more effectively by using DCB. Also, BER analysis has been shown through simulation at various power levels (5-20 dBm) and it has been shown that BER increases by increasing input launch power.