Abstract

In addition to displaying optical bistability, the laser containing a saturable absorber (LSA) is known to present self-pulsing which was called Passive Q-Switching(PQS) .This effect appears to be due not only to a simple destabilisation of the upper branch of the bistability curve but also to the interplay of the instability points of the laser. The dynamics of this purely optical system appears to be very rich .Chaos has been experimentally observed in a CO₂ laser containing CH₃I or SF₆ as a saturable absorber, and the transition towards chaos follows different scenarios depending on the interplay of the various instabilities present in the system. To be more specifics period-doubling cascade has been observed for small laser cavity detunings (<10 Mhz) and Shil’nikov-like dynamics have been observed for larger detunings (> 20 Mhz).. Another example of Shil'nikov dynamics in presence of several competing instabilities is given in the work of Arecchi et al on a CO₂ laser with feedback (1).

© 1988 Optical Society of America