Time and Modulation Frequency Dependence of Crosstalk in Homogeneous Multi-Core Fibers

This study presents an evaluation of the time and modulation frequency-varying power transfer of crosstalk in a homogeneous multi-core fiber (MCF). Experimental observations using a seven-core MCF over a period of 10 h show that, unlike localized crosstalk, distributed crosstalk power transfer has a pronounced modulation frequency response which changes substantially over time. This response is described using an adaptation of previous crosstalk models for MCFs showing that it results from the random time-varying interference between crosstalk contributions generated at a discrete number of phase matching points along the fiber. The model is used to produce simplified empirical models to characterize its average and variance. It is shown that both these quantities are nonzero and nearly constant for modulation frequencies above the inverse of the time skew between cores. These observations are validated by experimental data.