1 × 4 optical multiplexer based on the self-collimation effect of 2D photonic crystal

Abstract

In this paper, a novel 1×4 optical multiplexer (OMUX) based on the two dimensional photonic crystal embed cascaded Mach–Zehnder interferometer (MZI) employing self-collimation effect was proposed and its performance were numerically demonstrated. The 1×4 OMUX consists of four beam splitters and five mirrors. Light propagates in the OMUX employing self-collimation effect. The theoretical transmission spectra at different output ports of OMUX were analyzed with the theory of light interference. Then they were investigated with the finite-difference time-domain (FDTD) simulation technique. The simulation results indicate the cascaded Mach–Zehnder interferometer can work as a 1×4 optical multiplexer by selecting path length in the structure properly. For the drop wavelength 1550nm, the free spectral range of the OMUX is about 24nm, which almost covers the whole optical communication C-band window. The presented device that has no only a compact size but also a high output efficiency, may have practical applications in photonic integrated circuits.