Reduction of quantum noise in soliton propagation by means of phase-sensitive amplification

William L. Kath, Antonio Mecozzi, Prem Kumar +1 more

Izo I. Abram, Ivan Deutsch

Ivan Deutsch, Izo I. Abram

We study the possibility of employing phase-sensitive parametric amplifiers to compensate for losses incurred by solitons propagating in optical fibers. As phase-sensitive amplification is free from the excess spontaneous noise associated with laser amplifiers, the only quantum noise source in such a system arises from the fiber losses. In addition, under phase-sensitive amplification, fluctuations in the soliton frequency are squeezed to one half of the vacuum level, thus producing a negligible contribution to the fluctuations in the soliton arrival time. This greatly reduces the Gordon–Haus jitter of the solitons. The performance of the phase-sensitive amplifier is compared with that of alternative noise-reduction schemes employing phase-insensitive amplifiers and spectral filters as well as with the limits on long-distance data transmission imposed by quantum mechanics.

Franz X. Kärtner, H. A. Haus

Antonio Mecozzi, William L. Kath, Prem Kumar +1 more

Recently we have shown that stable soliton-like pulse propagation over ultra-long distances is possible in a nonlinear fiber line in which linear loss is balanced by periodic phase-sensitive (parametric) amplification.1 In such a line the length scale over which pulse evolution occurs is significantly increased beyond a soliton period because of the attenuation of phase variations across the pulse’s profile by the amplifiers. Here we examine the effects of quantum noise in the context of a storage ring for a bit stream of soliton-like pulses. We show that the one’s (soliton pulses) are asymptotically stable and the noise on the zero’s of the bit stream (absence of a soliton) is bounded. Moreover, we present evidence that the soliton-soliton interaction and Raman self-frequency shift are efficiently suppressed by the phase-sensitive amplifiers (PSA’s). The effects of direct timing noise and cubic dispersion in the fiber could also be decreased by using a pulsed pump (gain modulation) for the PSA’s.

Gil Fanjoux, Éric Lantz, F. Devaux +1 more