Abstract

A fascinating phenomenon of static spatial period doubling has been theoretically found to occur in a nonlinear interferometer with feedback field rotation [1]. Increasing feedback gain results in excitation of spatial sub-harmonics that perturb an optical reverberator (a first-order instability developing in the system). A bounded sequence of the static spatial period doubling bifurcations marks an initial stage of the transition to spatio-temporal chaos. Experimental studies of these effects have shown the importance of periodic boundary conditions for the angular distribution of the nonlinear phase modulation in the interferometer. This implies that the features of the period-doubling process essentially depend upon the spatial (angular) period of the basic reverberator [2]. A new spatio-temporal effect was experimentally observed. Stationary basic structure with an odd number of peaks is perturbed by a revolving wave, instead of a static sub-harmonic (that is observed in the case of an even number of peaks). Fig.1 illustrates what kind of optical structure we call "revolving defect" (RD).

© 1998 IEEE