Three-channel (de)multiplexer for dense wavelength division (de)multiplexing based on a photonic crystal AAH cavity

We propose a three-channel (de)multiplexer for dense wavelength division (de)multiplexing based on a photonic crystal Aubry–André–Harper cavity. The transmission performance of the designed structure was modeled and analyzed according to coupled mode theory. The parameters of the proposed device are calculated using a three-dimensional finite-difference time-domain method for verification. Numerical results show that the minimum insertion loss and linewidth at operating wavelengths of 1556.2 nm, 1555.4 nm, and 1554.6 nm are 0.47 dB and 0.2 nm, respectively. The channel cross talk is lower than − 16.23 d B . The (de)multiplexer has the advantages of low loss, small size [ 19.35 × 11.53 ( µ m 2 ) per channel], and easy cascading structure, and can realize three-channel dense wavelength division (de)multiplexing with a channel spacing of 0.8 nm and be used in highly integrated large-capacity optical fiber communication systems.