Systems engineering for long-haul optical-fiber transmission

Optical-fiber transmission systems application to long-haul optical trunk lines is studied. Development on optical transmission systems is found to be most advanced for short-haul interoffice systems, with many countries in the world already having systems in commercial use. This is largely due to the amount of demand that exists in this field, and that insufficient laser diode reliability does not permit constructing a long-haul optical circuit. However, from an economical viewpoint, optical transmission systems introduction into long-haul trunk lines is quite attractive. This paper reports the results of a survey on some economic and reliability aspects of the system, together with the technology state of the art. Attainable repeater spacings are estimated after detailed consideration of optical-fiber loss and dispersion. Some experimental results are also shown to clarify the transmission characteristics for high-speed signals and long repeater spacing systems. Based on the survey, future developmental targets are discussed.