Christian Sanchez Costa

Semi-Analytical Modelling of Linear Mode Coupling in Few-Mode Fibers

This paper reviews and extends a method for the semi-analytical solution of the coupled linear differential equations that describe the linear mode coupling arising in few-mode fibers due to waveguide imperfections. The semi-analytical solutions obtained proved to be accurate when compared to numerical solution methods. These solutions were integrated into a multisection model with split-steps for mode dispersion and mode coupling. Simulations using this model matched the analytical predictions for the statistics of group-delays in few-mode fiber links, considering different coupling regimes with and without mode delay management.

On the group delay statistics of few-mode fibres with intermediate linear mode coupling

We report an investigation on the statistics of group delay for few-mode fibres operating in the weak and strong linear coupling regimes as well as in the intermediate coupling regime. A single expression linking the standard deviation of the group delay spread to the fibre linear mode coupling is validated for any coupling regime, considering up to six linearly polarized guided modes. Furthermore, the study of the probability density function of the group delays allowed deriving and validating an analytical estimation for the maximum group delay spread as a function of linear mode coupling.

On the feasibility of mode-division multiplexed transmission over few-mode fibres

This paper reviews our most recent results on mode-division multiplexing systems based on few-mode fibres with low differential mode delay, spanning from the fibre design optimization to the receiver memory dimensioning. First, the fibre refractive-index profile is optimized for low differential mode delay and low macro-bend losses. Afterwards, we present a semi-analytical model of the linear mode coupling induced by fibre imperfections and stress. Finally, the interplay between the linear mode coupling and the differential mode delay is studied numerically and analytically, allowing to quantify the receiver memory required for a given fibre span.

Mid-link optical phase conjugation in lumped optical transmission systems

We report an analytical description of four wave mixing in lumped optical transmission systems deploying mid-link optical phase conjugator, and provide corroborating simulation results matching theoretical predictions for four wave mixing and for modulated signals.