Two-dimensional photonic crystal couplers with defect coupling region for wavelength division multi/demultiplexing

We propose a 3-port MUX/DEMUX structure, designed to separate n WDM channels in the range of 1500-1600 nm. The proposed structure has an advantage to change the refractive index value of the coupling rods of a PC coupler to optimize the performance of the WDM optical filters. The presence of the coupler in the PC structure substantially modified the transmission spectrum and transmission peaks (channels) appeared in the PC band gap. The change of refractive index of the coupling rods can be exploited to design optical switch and to reduce or enlarge a selected channel, without increasing the interaction length of the coupler.