On phase-modulational bifurcation during passive mode locking in lasers

We have found that phase-modulation instability of a single pulse due to nonlinearity of the refractive index of an in-cavity medium can cause the pulse to break up into several stable identical pulses of smaller amplitude. We show that if the refractive-index nonlinearity is greater than a critical value, then stabilization of the regime with several stationary pulses does not occur, and pulse multiplication accompanied by chaotic variation of the intensity continues until the cavity is completely filled with radiation. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 4, 261–264 (25 February 1998)