SPATIOTEMPORAL DYNAMICS DUE TO COMPETING SPATIAL INSTABILITIES IN A COUPLED LCLV FEEDBACK-SYSTEM

We investigate the effects of competing spatial instabilities on the d ynamics of transverse pattern formation in nonlinear optical feedback systems. In order to control the threshold intensities of two unstable wave numbers, a diffractive feedback is set up with a liquid crystal light valve as dispersive nonlinearity and two incoherently coupled fe edback loops of different lengths. In agreement with the results of a linear stability analysis, we found a region where a coexistence of sp atial instabilities leads to a complex spatio-temporal behaviour domin ated by irregular oscillations between the wave numbers involved.