We present a simple method to design one-dimensional (1D) multichannel filters based on the resonant coupling theory, which can choose not only the peak frequency of each channel but also the quality factors (Q values) independently. This method is described by three samples for the design of two-channel, three-channel, and four-channel filters. An additional defect is introduced symmetrically into both sides of the 1D PhCs—it can generate defect modes that overlap with the channels that require tuning. This defect makes the Q values of these channels reduced but with no frequency shift, while the other channels almost keep invariant. The method is valuable for the design of multichannel filters with each channel and bandwidth adjustable independently.
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