Article révisé par les pairs
Résumé : We consider a photonic crystal fiber resonator, driven by a coherent beam. The threshold for appearance of dark localized structures is estimated analytically and numerically by using a weakly nonlinear analysis in the vicinity of the modulational instability threshold. The nonlinear analysis allows to determine the parameter regime where the transition from supercritical to subcritical modulational instability takes place. This transition determines the threshold associated with the formation of dark cavity solitons. Numerical simulations of the governing model equation are in good agreement with the analytical results.