One kind of bandpassfilters based on PC have been proposed by R. Costa using PC-based Fabry-Perot (F-P)cavities in [6], and the partial reflecting mirrors of the F-P cavities are implemented byinserting appropriate defects into a two-dimensional (2-D) PC waveguide. In this kind offilters, reflectivity, phase and group optical lengths of the PC-based F-P cavities should becarefully designed to determine the resonance frequency and the bandwidth. Furthermore, therelative location of the inserted F-P cavities with respect to the lattice of the background 2-DPC should also be carefully designed to improve the filter performance, making an effectivedesign more difficult to achieve. In reference [7], one third-order Chebyshev bandpass filterbased on coupled defect resonators embedded in PC waveguide is designed in the range of theoptical communication frequency band. In this device, appropriate phase retardation betweenneighboring resonators has to be designed to avoid deep ripples in the passband. Therefore,the parameters of the defects of the resonators should be accurately designed to enhance thefilter performance.
đang được dịch, vui lòng đợi..