There are two major possible advantages to coherent optical transmission technology: (1) long-span transmission capability with high receiver sensitivity; (2) high-density frequency division multiplexing capability with high frequency selectivity. Here receiver sensitivity improvements experimentally achieved and the resulting long-span transmissions are reviewed. In the past few years there has been progress in both. Related technologies, such as the polarization controlling technique and the study of input power limitation by stimulated Brillouin scattering (SBS) in coherent optical fiber transmission systems, are also reviewed.
© 1987 Optical Society of AmericaPDF Article