NONLINEAR-OPTICAL AMPLIFIER BASED ON A DUAL-CORE FIBER

We propose a scheme for all-optical amplification based on a nonlinear -optical coupler in which one core is amplifying while another is atte nuating. In this scheme the input signal is fed into the amplifying co le, from where the output is also obtained. A weak input easily couple s to the lossy core and gets dissipated in it, whereas a stronger sign al stays and undergoes a nearly Linear amplification in the active cor e. When it is used for reshaping pulses in a long transmission line, t his scheme should allow the pulses to be amplified while simultaneousl y suppressing the noises between them. Simulating equations for the cw signal in this model, we are able to find a regime that provides for a strong contrast between the suppression of weak signals and amplific ation of strong ones as well as a steep transition from suppression to amplification at a certain threshold. (C) 1996 Optical Society of Ame rica