REDUCTION OF QUANTUM-NOISE IN SOLITON PROPAGATION BY PHASE-SENSITIVE AMPLIFICATION

We study the possibility of employing phase-sensitive parametric ampli fiers to compensate for losses incurred by solitons propagating in opt ical fibers. As phase-sensitive amplification is free from the excess spontaneous noise associated with laser amplifiers, the only quantum n oise source in such a system arises from the fiber losses. In addition , under phase-sensitive amplification, fluctuations in the soliton fre quency are squeezed to one half of the vacuum level, thus producing a negligible contribution to the fluctuations in the soliton arrival tim e. This greatly reduces the Gordon-Haus jitter of the solitons. The pe rformance of the phase-sensitive amplifier is compared with that of al ternative noise-reduction schemes employing phase-insensitive amplifie rs and spectral filters as well as with the limits on long-distance da ta transmission imposed by quantum mechanics.