Blowout bifurcation in a system of coupled chaotic lasers

We show that loss of synchronization of two identical coupled chaotic class B lasers can occur via a blowout bifurcation. This occurs when a transvers e Lyapunov exponent governing the stability of a synchronized subspace pass es through zero. A system of two laterally coupled lasers with modulated pa rameters is investigated numerically in a region of chaotic behavior. A tot al of five invariant subspaces are shown to exist. Evidence of a blowout fr om one of these subspaces is found in Lyapunov exponents and in the presenc e of on-off intermittency for small enough coupling strengths. At all param eter values investigated, the phases of the electric fields are shown to be precisely synchronized even though the amplitudes may fluctuate chaoticall y and independently. We discuss the implication that there will be bubbling effects in laser systems in the presence of noise and imperfections. [S106 3-651X(98)01012-5].