Design and performance analysis of eight channel demultiplexer using 2D photonic crystal with trapezium cavity

Abstract In this work, an eight-channel dense wavelength division multiplexing demultiplexer is designed with a 2D photonic crystal triangular lattice. The proposed demultiplexer consists of a centre bus waveguide, an isosceles trapezium resonant cavity, and an eight-circular ring cavity (CR1, CR2, CR3, CR4, CR5, CR6, CR7, and CR8). The point defect resonant cavity consists of seven rods to drop different wavelengths from eight cavities, each of eight drop waveguides. The design is very simple to realise. The finite difference time domain and plane wave expansion method methods were used to analyse the proposed design’s band structure and transmission spectrum. The resonant wavelengths are 1.5441 μm, 1.5443 μm, 1.544 49 μm, 1.5447 μm, 1.5449 μm, 1.5451 μm, 1.5453 μm, and 1.5455 μm respectively. The proposed device provides a high-quality factor, transmission efficiency, and low crosstalk. The device’s footprint is 490.0 μm2, which can be easily incorporated into photonic integrated circuits.