The Study of Information Capacity in Multispan Nonlinear Optical Fiber Communication Systems Using a Developed Perturbation Technique

We study the information capacity for a multispan optical fiber transmission system with losses, dispersion, nonlinearity, and amplified spontaneous emission noise. A perturbation technique is developed to examine the information capacity, and a semianalytic expression of the conditional probability distribution function is determined initially. A novel semianalytical form of the information capacity was obtained, which can be extended to the wavelength division multiplexing optical fiber communication systems. Computer simulations are executed for various parameters of the transmission system. The studied results indicate that the capacity does not monotone increase with the input power and is affected by the nonlinear coefficient and bit rate prominently.