All-optical ultrafast switching in a silicon microring resonator and its application to design multiplexer/demultiplexer, adder/subtractor and comparator circuit

In this paper, the possibility of using a silicon waveguide based microring resonator as a nonlinear all-optical switch is described under low power operation through a two-photon absorption effect. All-optical multiplexer/demultiplexer scheme based on two cascaded microring resonators has been proposed and described. The proposed circuits require smaller number of ring resonators and a single circuit consisting of two microring resonators capable to perform both multiplexer/demultiplexer operations by simply interchanging the inputs and outputs. Two optical pump signals represented the two operands of the logical operations to modulate the two microring resonators. The demultiplexer circuit can also perform as a half-adder/subtractor and a single bit data comparator. Numerical simulation results confirming described methods are given in this paper. The performances of the schemes are analyzed by calculating the extinction ratio, contrast ratio and amplitude modulation of the resulting data streams.