Novel All-Optical Switch Using Nonlinear Mach-Zehnder Interferometer

Using a nonlinear Mach-Zehnder interferometer, a novel all-optical switch that can mimic NOT/XOR, AND, and NAND gates is proposed. The proposed switch is novel in the sense that it functions with mutually incoherent input beams of the same wavelength and polarization, and the NOT/XOR and NAND gates constructed using it give pure output (i.e., output contains only one of the all-input beams and not a mixture of the input beams). Purity of output is an important feature as it is essential for cascadability. The operating power levels of the proposed switch could be adjusted by adjusting the length of the Mach-Zehnder interferometer that makes the proposed switch easily implementable in a circuit. Moreover, a cascadable NAND gate allows for Boolean completeness.