All-optical decision gate circuits using cascaded periodically poled lithium niobate devices

We propose a cascaded periodically poled lithium niobate device. In the device, two lithium niobate crystals with different quasi-phase matching wavelengths are cascaded. We numerically show that the cascaded periodically poled lithium niobate device has an all-optical level discriminating characteristic, thus enabling a compact and stable ultra-fast 3R circuit.