Abstract

In recent years it has been recognized that the existence of amplitude or power instabilities has possible utility in the area of all-optical switching.¹ Jensen’s proposal² for spatial switching in a two-waveguide directional coupler represents the seminal contribution in the field. As pointed out by Christodoulides et al.³ however, Jensen’s two-waveguide coupler may be considered only a special case of more general class of n-oscillator systems. We consider in this paper the obvious extension from two to three elements. In the linear regime the behavior of the three-guide coupler is similar to that of the conventional two-guide coupler, except for an intermediate transfer of power in to the center wave guide. For devices that are one coupling length and one beat length long the transmission characteristics of the three-waveguide coupler are markedly sharper than in the two-waveguide case and approach the characteristics of an ideal switch. At long range the field trajectories of the three-guide coupler become chaotic in the vicinity of two critical power levels.

© 1990 Optical Society of America