QUASI-PERIODIC ROUTE TO CHAOS IN ERBIUM-DOPED FIBER LASER

We present experimental evidence of quasiperiodic route to chaos in erbium-doped fiber laser operating simultaneously at 1.550 mu m and 1.536 mu m. Starting from a CW state for high pumping rates the system becomes T-periodic, 2T-periodic, 3T-periodic and chaotic for decreasing pumping ratios. The Loci-frequency spectra shows two fundamental frequencies, The nT-periodic regimes correspond to a frequency locking of the low frequency on a subharmonic of the high frequency, An adapted model based on the rate equations is numerically investigated and leads to a good qualitative agreement with the experimental data.