Modeling and designing of Chebyshev type coupled photonic crystal filters based on coupling matrix

A method for modeling and designing of coupled resonators photonic crystal (PC) filters for wavelength division multiplexing (WDM) systems is presented. This proposed method is based on coupling coefficients of intercoupled resonators and the external quality factors of the input and output resonators based on the circuit approach. A general formulation for extracting the two types of parameters from the physical structure of the PC filters is given. At last, we redesign a third-order Chebyshev filter which has a center frequency of 193.55THz, a flat bandwidth of 50GHz, and ripples of 0.1 dB in the pass-band. The filter's structure derived from the proposed method is more compact.