Simulations of a few-mode fiber optic link

This work presents simulation of long-haul fiber optic link with few-mode fibers. Proposed model is, based on system of coupled nonlinear Schrodinger equations. We utilize combination of split step method and earlier on developed solution for optical fiber analysis based on Gaussian approximation. Presented model takes into account fiber dispersion and nonlinearity as well as its irregularity and mode coupling. It takes into account both the non-linear mode coupling and linear mode coupling. For simplicity, we assumed that the spans of amplification are the same and the span losses are, compensated by the optical amplifier fully. The amplified spontaneous emission (ASE) of Erbium doped fiber amplifiers (EDFA) under simulation is took into account too. In our investigation, we considered three examples of mode multiplexing. In the first example, only one of guided mode is, used for data transmission. In this case, the mode filters are set on input and output of the line amplifiers along the line. In the second example, the two LP modes are, used together as a space channels. And in the third example the vortex mode are used as a space channels. In the all cases, the mode multiplexors are set on output of the fiber optic link. We performed analysis of error probabilities for these examples. Here the systems with DQPSK format of modulation and 100 Gb/s per optical channel were considered. All results of simulation for mentioned examples were, compared with data of simulations for fiber optic link with single mode optical fiber.