A hybrid multiplexer/de-multiplexer for wavelength-mode-division based on photonic crystals

A hybrid multiplexer/de-multiplexer (HMUX/HDeMUX) for wavelength-mode-division based on photonic crystals (PCs) is presented. The proposed device consists of a point-defect cavity, a wavelength-selective cavity and asymmetrical parallel waveguides. Coupled-mode theory (CMT) is applied to the analysis, and the finite-difference time-domain (FDTD) method is used for the simulations. The simulation results show that the device can multiplex the fundamental and first-order modes of 1550 and 1310nm. It exhibits not only a low insertion loss (<0.37dB) but also low mode crosstalk (<-13dB). Thus, the PC-based HMUX/HDeMUX has considerable potential for application in large-capacity optical communication systems.