Optoelectronic device technology for coherent optical communication systems

Optical heterodyning, the principle incorporated in coherent optical communication systems, is of great interest in present‐day fiber‐optic research because it offers the ability to construct very sensitive optical receivers and to transmit and demultiplex large numbers of closely spaced optical channels carried on a fiber, thus leading to efficient use of the fiber bandwidth. The requirements on materials for heterodyne receivers and semiconductor lasers—indispensable components of coherent optical communication systems—and recent progress made toward satisfying these requirements are discussed, together with device technologies in this field.