Coherent, Self-Coherent, and Differential Detection Systems

Abstract

In order to meet the ever-increasing demand in telecommunication capacity, fiberoptic communication systems have been evolving dramatically over the past decade [1, 2]. The fiberoptic communication traffic growth has been at a rate of about 2 dB per year, representing a traffic increase of a factor of 100 in 10 years [1, 2]. The capacity increase in fiberoptic communication systems has been achieved mainly by deploying more fiber links, populating more wavelength channels per fiber link through dense wavelength-division-multiplexing (DWDM), and increasing the data rate per wavelength channel. In addition to increased capacity, the cost per bit in terms of both capital and operational expenditure has been decreased to sustain the traffic growth. Increasing the data rate per wavelength channel is regarded as an effective way to provide both increased capacity and lowered cost per bit.