DISPERSION COMPENSATION WITH PHASE-SENSITIVE OPTICAL AMPLIFIERS

Recently, we proposed a novel approach to combating the pulse-broadening effect of group-velocity dispersion (GVD) in a fiber-optic communication link (IEEE Photon. Technol. Leu., vol. 5, pp. 669-672, 1993). In our scheme, linear loss in the fiber is balanced by a chain of periodically spaced, phase-sensitive optical amplifiers. In this paper, we present a detailed analysis of pulse propagation in such a fiber line showing that, due to attenuation in the quadrature orthogonal to the amplified quadrature, it is possible for a pulse to propagate without significant broadening over lengths many times longer than the usual dispersion length of the fiber. An averaged equation for pulse evolution over distances longer than the amplifier spacing is derived. The effect of optical-phase fluctuations between the propagating pulse and the amplifiers is also considered. Since our proposed scheme does not rely on the formation of solitons in the fiber, it can be implemented in both the positive and negative GVD regions, and it does not require a minimum peak power for the pulses.