Optimization of Configuration of Directional Coupler in Hexagonal Resonator in Photonic Crystal

To establish transmission in a network using only optical signal communication, two waveguides were aligned in parallel in a two-dimensional photonic crystal structure and their coupling lengths were investigated. The transmission characteristics of hexagonal resonators situated in middle of the parallel waveguides with varying lengths of the coupling region were then analyzed. Electromagnetic wave propagation simulations were performed by band-limited input signal and the transmitted power were compared at the output ports. As a result, it was found that frequency components can be separated simply by changing the length of the coupling region. This can be applied to drop the desired channel by demultiplexing from wavelength division multiplexed (WDM) signals.