Stability of multiple pulses in optical fibers with phase-sensitive amplification and noise

We demonstrate via numerical simulations the long-term stability of bound 2- and 3-pulses in a fiber-optic communication or storage system where loss is compensated by periodic, lumped, phase-sensitive amplification. The effects of attenuator quantum noise induced by linear loss in the fiber and of guided acoustic-wave Brillouin scattering caused by coupling to acoustic modes of the fiber are included in the computations. The first noise source is shown primarily to produce a small amount of intra-pulse timing jitter, while the second is shown mainly to cause pulse energy fluctuations. For amplifier spacings that are not too large, however, both effects are smaller than in systems using phase-insensitive amplification. It is suggested that these 2- and 3-pulses could be used in a novel encoding scheme to improve transmission system bit rates.