The starting mechanism in coupled-cavity modelocked laser systems

We present what we believe to be the starting mechanism in coupled-cavity additive pulse modelocked (APM) laser systems. The etalon effect of the coupled cavity forces the main cavity to lase at two separate frequencies, thus producing short and strong mode beating "noise bursts" that can overcome dynamic gain saturation in large emission cross-section gain media. As a result, self-starting is possible for the NaCl:OH coupled-cavity color center laser. The dependence of the etalon effect on the cavity length detuning and its role in the dynamics of the APM process and in self-stabilized picosecond coupled-cavity lasers are discussed. The experimental observation of THz-mode beating fluctuations produced by the mode structure of a coupled-cavity NaCl:OH color center laser supports our model.<
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