Effects of randomly varying birefringence on soliton interactions in optical fibers

Abstract

The effect of a randomly oriented birefringence on soliton interaction is studied numerically. The random variation in birefringence in linearly birefringent fibers is modeled by random shift in orientation of the birefringence axes and a random phase difference between the pulse amplitudes in the two polarizations which occurs periodically. Analytical calculations show that the averaged behavior is governed by the Manakov equation.¹ The evolution of a pair of solitons with an initial pulse separation T₀ ranging from 2τ to 70τ is studied, where T is the soliton pulse width. It is observed that for T₀ < 10τ the interaction is dominated by the phase-dependent short range interaction. The randomly varying birefringence leads to breakup of a two-soliton pair that is originally in phase. For T₀ > 10τ, the solitons interact through the dispersive radiation that is generated by the random birefringence, but the interaction is too weak to explain the phase independent long-range interaction observed experimentally.³