Photonic crystal waveguide-based Mach-Zehnder demultiplexer

A Mach-Zehnder demultiplexer with two different waveguide arms is proposed and studied theoretically in photonic crystal. The two waveguide arms with different widths function as a phase shifter. The operating wavelength spacing depends on the length of the two waveguide arms. The photonic bandgap is calculated by the plane-wave expansion method, and the device is simulated by the finite-difference time-domain method.