Effects of modulational instability on coherent transmission systems

Abstract

The modulational instability of light waves in fibers with anomalous dispersion produces growth of initial sidebands generated in coherent transmission systems. Since the growth rate is proportional to the carrier intensity, the repeated amplification of the carrier degrades the signal-to-noise ratio in proportion to the product of the number of amplifications and the initial carrier intensity. With nominal parameters in a system of a few milliwatts of power, the e folding distance of the signal-to-noise ratio becomes of the order of a few hundred kilometers.