All-optical polarization switching based on Bragg-spaced quantum dots layers

One kind of Bragg-spaced all-optical switching has been proposed in this paper, and the quantum dots ensembles are used in it as active layers. By one-dimensional photonic crystal theory and transmission matrix method, we have studied the reflectivity stop band and switching effect based on the ac Stark effect. The reflectivity stop band of this switch can be suppressed or recovered, and the circular dichroism and birefringence are induced by a circle-polarized control light, which result in a significant polarization switching effect. This switching structure shows great advantages of lower requirement of pump light intensity, larger contrast ratio than that of Bragg-spaced quantum wells with the same period, especially this switching can be used at room temperature theoretically. So we predict that there are prodigious prospects for its using in high speed optical communications as all-optical switching.