SOLITON LATTICE AND GAS IN PASSIVE FIBER-RING RESONATORS

We consider multisoliton patterns in the model of a synchronously pump ed fiber-loop resonator. An essential difference of this system from i ts long-line counterpart is that, due to the finite length, dynamical regimes may be observed that would be unstable in the infinitely long line. For the case when the effective instability gain, produced by co mpetition of the modulational instability (MI) of the flat background and losses, is small, we have consistently derived a special form of t he complex Ginzburg-Landau equation for a perturbation above the conti nuous wave (cw) background. It predicts bound states of pulses with a uniquely determined ratio of the pulse width to the separation between them. Direct numerical simulations have produced regular soliton latt ices at small values of the feeding pulse power, and irregular pattern s at larger powers. Evidence for a phase transition between the lattic e and gas phases in the model is found numerically. At low power, the width-to-separation ratio as found numerically proves to be quite clos e to the analytically predicted value. We also compare our results wit h recently published experimental observations of MI-stimulated format ion of a pulse away in a mode-locked fiber laser.