Dynamic modulation of localized defect states in multichannel photonic crystal waveguides

The localized defect states (LDS) can usually be obtained by introducing dielectric defects or dielectric disorder into photonic crystals. Here, we introduce a new method to dynamically generate LDS, which can be realized in multichannel photonic crystal waveguides by modulating the position, polarization and phase of multiple dipole sources. We propose a general theory to obtain the localization conditions. When multiple dipole sources satisfy the localization condition, LDS can be generated. Unlike the traditional LDS, the size and position of the LDS in our method can be adjusted by the control of the dipole sources. In addition, the conversion of LDS and waveguide mode can be realized easily by the modulation of the dipole sources.