Simulation of a few-mode signal propagation over multimode fiber link with differential mode delay compensators

Abstract

Simulation results of a few-mode signal propagation over multimode fiber link, been excited by laser source, are represented. The link includes conventional multimode fiber with graded-index profile, and differential mode delay (DMD) compensating multimode fiber, been installed at the receiver end. A real refractive index profile samples of different fiber generations, been measured by analyzer EXFO NR-9200HR, are considered as prototype of link fiber. Recently proposed so-called reverse DMD fibers (RDMDF) are applied to compensate mode delay. Here DMD compensation is based on following effect: the initial array of excited mode group velocity diagram is reversed in reference to the fastest mode. This effect is obtained by synthesis of special graded profile, based on optimization with objective function, been represented as a sum of squares of deviations between points, corresponding to radial mode orders, of ideal desired reverse group velocity diagram and diagram of current iteration. Time-domain model of piece-wise regular multimode fiber link is applied to simulate laser excited a few-mode pulse propagation. The model takes into account DMD and higher-order mode chromatic dispersion. Results of pulse dynamics calculation during propagation over described multimode fiber link under DMD compensation effect are represented.

Few-mode fibers for mode division multiplexing transmission

“…The total DMD of FMF is a few orders of magnitudes larger than that induced by PMD. In "coupled" MDM, some DMD compensation may be required [13,14]. In "uncoupled" MDM, the DMD does not degrade the transmission characteristics.…”