Nonlinear propagation in multi-mode fibers in the strong coupling regime

Abstract

We show that light propagation in a group of degenerate modes of a multi-mode optical fiber in the presence of random mode coupling is described by a multi-component Manakov equation, thereby making multi-mode fibers the first reported physical system that admits true multi-component soliton solutions. The nonlinearity coefficient appearing in the equation is expressed rigorously in terms of the multi-mode fiber parameters.

Birefringence effects in multi-core fiber: coupled local-mode theory

“…On the other hand, in [14][15][16][17] the Manakov equations have been extended to multi-mode fibers (MMFs) and multi-mode multi-core fibers (MM-MCFs) to analyze linear and nonlinear propagation in SDM systems modeling intra-and inter-core coupling effects. In addition, in [18,19] the mode coupling has also been theoretically investigated in MMFs and MM-MCFs considering both orthogonal polarizations and the longitudinal random perturbations of the fiber.…”

“…In [18] the bending and twisting of the media were modeled in the coupling matrix (composed by the coupling coefficients of the coupled-mode theory proposed in [20] for anisotropic optical waveguides), and in [19] the spatial random perturbations were included in the propagation matrix of the optical media. In all these previous works [8][9][10][11][12][13][14][15][16][17][18][19], the longitudinal perturbations of the fiber have been described assuming ideal modes but omitting the temporal fluctuations of the SDM fiber perturbations.…”

Impact of power allocation strategies in long-haul few-mode fiber transmission systems

“…Also, it is worth mentioning that more advanced modeling approaches have been elaborated as well, e.g [6], assuming isotropic mode coupling statistics, and thus generalizing the Manakov theory for multimode fibres; however in the next sections we will clearly demonstrate that in the regimes of interest, the qualitative conclusions are well predicted by our model. The total transmission distance was fixed to 1,600km, and the link consisted of 80km spans, no inline dispersion compensation and single-stage erbium doped fiber amplifiers (EDFAs).…”

“…One such challenge is associated with linear and nonlinear mode coupling effects, which strongly connect the achieved capacity to the achievable transmission distance [6][7][8]. Index perturbations in fibers, whether intended or not, can induce coupling between signals in different modes, and can cause propagating fields to evolve randomly.…”

“…crosstalk between spatially multiplexed signals, end-to-end group delay spread of signals, mode dependent loss/gain, etc [9]. Recently, a few preliminary reports analyzing propagation impairments considering both linear [10] and nonlinear coupling [6] have been reported, however the recent developments in spatially multiplexed systems demand not only a deeper and clearer understanding of coupling effects, but also their impact on system design choices.…”