Electronic Equalization of Fiber Optic Links

The days when optical fiber was viewed as having unlimited capacity have come to an end due to the steady growth in demand for bandwidth. Dispersion, noise and nonlinearities pose substantial channel impairments that need to be overcome. As a result, over the last decade, signal processing has emerged as a key technology to the advancement of low-cost high data rate optical communication systems. The unrelenting progress of semiconductor technology exemplified by Moore´s Law provides an efficient platform for implementing signal processing techniques in the electrical domain leading to what is known as electronic dispersion compensation (EDC). In this paper, we provide an overview of some of the driving factors that limit the performance of optical links and provide a design example of an MLSE-based receiver for 10 Gb/sec long haul links.