Performance analysis of subcarrier multiplexed WDM transmission system in presence of fiber nonlinear effects

Abstract

A theoretical analysis for crosstalk level in a subcarrier multiplexed WDM (SCMWDM) transmission system is presented. Crosstalk due to fiber nonlinear effect is considered as Stimulated Raman Scattering (SRS), Cross Phase Modulation (XPM) and Four Wave mixing (FWM). Analysis is carried out to find the expression for the electric field due to signal and crosstalk at the output of the fiber considering an SCM- WDM signal at the fiber input including the effect of fiber nonlinear effect in a single mode fiber. The type of subcarrier modulation is considered as minimum shift keying (MSK) with optical intensity modulation for the WDM signal. The analysis includes the effect of crosstalk for a direct detection receiver with coherent demodulation of the subcarrier modulated signals. The expression for the carrier power to noise plus crosstalk power ratio and the expression for BER are derived. Performance results are evaluated for a given fiber length and number of WDM wavelengths for standard Single mode fiber as well as Dispersion shifted fiber at bit rates of 10 Gb/s or more. OptiCal system optimizing parameters such as optimum input transmitter power, channel separation of wavelength channel, number of WDM channels is evaluated for a BER of 10-