Minimization of FWM effect in nonlinear optical fiber using variable channel spacing technique

Optical Fiber Communication widely implements Dense Wave Division Multiplexing (DWDM) technique in order to accommodate large number of channels within a limited bandwidth. But, this technology suffers a serious degradation in signal quality due to inter-channel interference. Optical Kerr Effect, in addition to this, worsens the situation. This paper deals with minimization of Four Wave Mixing (FWM) impact, one of the Optical Kerr effects, by using variable channel spacing instead of conventional fixed channel spacing technique. FWM effect generates spurious components at multiple frequencies, whose effective amplitude can be reduced using different channel spacing. Bit Error Rate (BER) observed for different length of fiber has been analyzed with an aim to estimate the difference between variable channel spacing algorithms. Obtained results have shown that BER of 10-11 can be reached with 153.7 km long fiber for fixed channel spacing while the usage of variable channel spacing method keeps the same BER level with 160.5 km long fiber.