ABSTRACT
This chapter presents the processing of digital signals using higher-order spectral techniques to evaluate the performance of a coherent transmission system, especially the bispectrum method in which the signal distribution in the frequency domain is obtained in a plane. It also presents the processing of optical signals before the optoelectronic detection in the optical domain in a nonlinear (NL) optical waveguide as an NL signal processing technique for digital optical receiving systems for long-haul optically amplified fiber transmission systems. The chapter deals with the photonic processing of optically modulated signals prior to the electronic receiver for long-haul optically amplified transmission systems. It provides a brief introduction of the triple correlation and bispectrum processing techniques and introduces the simulation platform for the long-haul optically amplified fiber communication systems. The performance of the transmission system is given with evaluation of the bit-error rate under linear and NL transmission re.
