generation of optical communication systems and provide new capabilitie s that
were not possible without the detection of the phase of the optical signal.
3.1.3 Organization of this Chapter
This chapter reviews the results of recent developments on the digital coherent
receiver. After historical perspective given in Section 3.1, Section 3.2 provides the
principle of coherent detection. Section 3.3 discusses the concept of the digital
coherent receiver, and the basic performance of the digital coherent receiver is
evaluated in Section 3.4. Section 3.5 deals with postprocessing functions, which
enable compensation for transmission impairments at the receiver. Finally, a
summary is provided in Section 3.6.
3.2 PRINCIPLE OF COHERENT DETECTION
In this sectio ...