SPACING OF LUMPED AMPLIFIERS IN SOLITON TRANSMISSION

Lumped amplifiers evenly spaced along a fiber represent a very importa nt solution for attenuation compensation in the case of soliton transm ission [1, 2, 6 - 15]. This paper deals with the problem of evaluating (in the absence of noise) the maximum amplifier spacing compatible wi th the conditions for soliton propagation. The analysis is based on a simple approach to solitons, and it attains physical evidence by makin g reference to a well-known property, i.e. that solitons in the lossle ss fiber [1 - 5] are able to produce a continuous compensation between a modulation angle due to dispersion and a modulation angle due to no n-linearity. The first paragraph will illustrate the mentioned approac h for the lossless fiber, which will be extended, in the last paragrap h, to the attenuating fiber with lumped amplifiers.