THE IMPACT OF OPTICAL AMPLIFIERS ON LONG-DISTANCE LIGHTWAVE TELECOMMUNICATIONS

Erbium-doped fiber amplifiers (EDFA's) and wavelength-division-multiplexing (WDM) technology offer unprecedented capability to expand transmission capacity in long-distance telecommunications. Properties of EDFA's are nearly ideal for application in lightwave long-haul transmission. Nonlinear effects in the transmission fiber and amplifier spontaneous emission noise limit the performance and therefore dictate the design of long-distance amplified systems, especially those employing WDM. The next-generation transoceanic system will use EDFA's as repeaters, yielding a capacity almost ten times larger than what is available today. Multichannel WDM soliton transmission promises further substantial enhancement. Terrestrial long-haul networks will also benefit greatly from amplified WDM systems designed to ''mine'' the large inherent bandwidth in the embedded fiber. The ten- to fifty-fold capacity increase over present systems not only will provide for ample growth, but more importantly will enable network operators to enhance operational flexibility and network functionality, and to facilitate a fast-recovery, self-healing capability through cost-effective redundant routing.