Numerical solutions for two sets of equations describing lasers with i
ntracavity saturable absorbers were studied for their instabilities as
sociated to passive Q-switching. For realistic values of parameters of
CO2 lasers, we have demonstrated that two independent chaotic lasers
can to into synchronized periodic oscillation after 3% of coupling. If
both lasers start from periodic oscillation, after coupling they can
go into either synchronized periodic or synchronized chaotic oscillati
ons depending on the coupling strength. The coupling can be made eithe
r through absorber, laser pin or both.