Decoupling of Multiple Coupled Photonic Crystal Waveguides

Decoupling of multiple coupled photonic crystal waveguides (M-CPCWs) is investigated based on the self-imaging principle. We choose the three-, four-, and eight-CPCWs as typical structures to discuss the general characteristics of the M-CPCWs. It is found that around the frequency where the multiple guided modes are almost degenerate, the power transfer in the M-CPCWs is eliminated for any entrance. The frequency region for decoupling is insensitive to the number of coupled waveguides with the extinction ratios higher than -15 dB. The decoupling of the M-CPCWs exhibit many advantages and may have practical applications in photonic integrated circuits.