All-optical NOT and AND gates using counter propagating beams in nonlinear Mach–Zehnder interferometer made of photonic crystal waveguides

Counter propagating beams (inputs) through nonlinear Mach–Zehnder interferometer (NMZI) with Kerr type nonlinearity and made of photonic crystal waveguides (PCW) are simulated using two dimensional finite difference time domain (FDTD) method. It is shown that PCW based NMZI of proper parameters could be used as NOT and AND logic gates. The results obtained here are compared with earlier published results of NMZI made of conventional step index waveguides (SIW). Operating powers and/or device length would be much smaller in case of PCW based NMZI as compared to SIW based NMZI if same nonlinear material is used.