Experimental and theoretical investigation of nonlinear-crosstalk in SCM-WDM CATV systems

The generation of crosstalk in wavelength division multiplexed cable television (WDM-CATV) networks due to fiber-induced nonlinearities is studied, both theoretically and experimentally. For the first time, to our knowledge, the contribution of electrostriction to the generated crosstalk level in such systems is included in an analytical model. The critical parameters of the system are defined and analyzed and their impact on the formation of the nonlinear crosstalk is examined. The comparison between the theoretical results and the experimental data reveals very good agreement and has allowed the optimization of the performance of the system in terms of its critical parameters. For fixed channel numbers, twofold reduction in channel spacing increases the crosstalk by 3 dB/ch. For fixed channel spacing, doubling the number of channels results in 1 dB/ch crosstalk increase.