Abstract

Erbium doped fibre amplifiers now allow the possibility of deploying optically transparent systems over trans-oceanic and trans-continental distances. However it is now well established that fibre non-linearities cannot be ignored in such systems. For example, when a single channel system is operated in the anomalous dispersion régime, ie. with λ > λ₀ where λ₀ is the wavelength of zero chromatic dispersion, self phase modulation (SPM) may lead to pulse compression or pulse break up. When operated with λ < λ₀, SPM leads to increased dispersion and pulse broadening. A choice may be made to avoid the non-linearities as far as possible; for example by minimising the amplifier spacing, by using the minimum optical power consistent with the required electrical signal-to-noise ratio (SNR) and by careful choice of the operating wavelength with respect to λ₀. Alternatively, one may choose to use actively the fibre non-linearity to design a soliton based system operating in the anomalous dispersion régime. This paper attempts to consider some of the design constraints for such a system. In particular it considers a system operating at 5Gbit/s over a total distance L_sys of 6000km.

© 1991 Optical Society of America