Irregular phase slipping in a model for a laser with injected signal

In a model for a single mode laser with injected signal we find irregular pulsing of the output signal. During the turbulent time intervals the relative phase between the internal and the external field slips by an integer multiple of 2pi, where the multiplicity varies irregularly from pulse to pulse. Between the pulses, in the laminar time intervals, the relative phase is locked. We compare this behavior with the results of various other laser models. By the investigation of this interesting mechanism for the creation of phase chaos in a driven oscillator, we learn which properties are responsible for the irregular interruption of the phase locking. (c) 1997 American Institute of Physics.