Evaluation of the Contribution of Fiber Dispersion in SNR and BER Performance for an Optical TDM Link

Abstract

The contribution of fiber dispersion in the deterioration of bit error rate (BER) performance for an optical time division multiplexed (TDM) link is illustrated in this paper. Signal to noise ratio (SNR) and BER is calculated according to the conventional way i.e. by only considering receiver noise. An analytical model is developed to compute the signal to noise and crosstalk ratio (SCNR) where the additional crosstalk is the contribution of dispersion. Such crosstalk occurs due to the overlapping of pulses with the neighboring pulses which is called inter-symbol-interference (ISI). Dispersion causes pulses to get broadened for which ISI occurs. By comparing the results obtained from this analytical model with the conventional process the crosstalk due to dispersion is determined. The model which is validated by MATLAB shows that the more the dispersion increases the more the crosstalk occurs and as a consequence, the more the signal suffers. The power penalty due to dispersion is also computed comparing the conventional computational method where the result indicates a non-linear incremental pattern of such penalty for increasing the degree of dispersion. The penalty becomes higher than 1 dB for the value of dispersion index from 0.08 to above.