Correlation between the chaotic emissions of two coupled erbium-doped fibre ring lasers

We present experimental and numerical results of the correlation between the chaotic emissions of two coupled erbium-doped fibre ring lasers whose pump powers are modulated with a sine-wave signal. Experimentally, it is observed that correlation does not increase monotonously as the coupling becomes stronger: for certain intermediate coupling conditions, a correlation minimum is found. This non-monotonic dependence is also found in the numerical simulations performed, which in general provide an acceptable qualitative agreement with the experimental results.