Variational Approach to Dynamics of Bright Solitons in Lossy Optical Fibers

A variational analysis of dynamics of soliton solution of coupled nonlinear Schrödinger equations with oscillating terms is made, considering a birefringent fiber with a third-order nonlinearity in the anomalous dispersion frequency region. This theoretical model predicts optical soliton oscillations in lossy fibers. 1. Introduction. The propagation of bright solitons in birefringent optical fibers has been the subject of intensive theoretical and experimental investigations during the past two decades. The solitons are nonlinear pulses in fibers when the nonlinearity induced by the optical intensity balances the dispersion of the fiber. Studies of bright soliton propagation in fibers are demanding with reference to the development of soliton-based optical communication, generation of short pulses, and soliton lasers. The idea of exploiting these solitons as natural bits to transmit optical data motivates important research efforts towards the development of models [2, 3, 5, 6, 7, 8, 9] describing solitary wave propagation in optical fibers under different conditions. In lossless, one would not expect solitons to distort in either the time or frequency domains regardless of the distance over which they propagate. This supposition is, however, not true in the case of lossy fibers. In this paper, we follow an adiabatic approach using a variational technique [1] to study dynamics of bright solitons generated from semiconductor lasers in a lossy birefringent fiber.