Introduction: Coherent Optical Communication

Coherent Optical Communication Systems

The rapid evolution of long-haul optical communications systems, witnessed in the last five years, is due to the gradual adoption of spectrally efficient, multilevel modulation formats, in conjunction with polarization division multiplexing (PDM) and coherent intradyne detection assisted by digital signal processing (DSP). The objective of this tutorial chapter is to briefly review the operatin...

Compact Optical Receivers for Coherent Optical Communication

Communication traffic is increasing continuously along with the expansion of video streaming service and the popularization of smartphones and other mobile devices requiring high-speed, large-capacity transmission. Digital coherent optical communication technology using multilevel modulation formats has already been used for long haul systems and is now attracting attention as a means of long-d...

Terrestrial Coherent Free-Space Optical Communication Systems

In the past three decades, the demand for high-speed communications has increased dramatically, while fiber optical communications has been applied in the majority of data transmission networks. Optical fiber has advantages over existing copper wire in long distance and high demand applications. The ever increasing need for higher bandwidth and higher speed optical data and communications trans...

Optical Communication with Weak Coherent Light Fields

Coherent Optical Multiple-Input Multiple-Output communication

We propose and demonstrate the Coherent Optical Multiple-InputMultiple-Output (COMIMO) communication technique. In analogy to the spatial diversity in wireless communication, the concept exploits the modal diversity, inherent in a multi-mode fiber (MMF), to transmit independent data channels through a single fiber without the need for wavelength division multiplexing. Central to the MIMO concep...