Multichannel double-polarization bandpass optical filter utilizing evanescent wave

A multichannel double-polarization bandpass optical filter, which has the performance of variable channel interval, is theoretically proposed. The filter consists of a stack of two one-dimensional photonic crystals (1D PCs). Based on the resonant couple of evanescent waves localized at the interfaces between neighboring layers, the linear transmission properties of the filter are numerically simulated by the transfer matrix method. The simulation results show that channel number of the filter can be changed by varying the thickness of the middle layer in the centrosymmetric 1D PC structure, while the bandwidth and wavelength of the channel can be adjusted by the incident angle of light. This work may be helpful in designing multichannel double-polarization bandpass optical filter in optical communication systems.