Design of an add filter and a 2-channel optical demultiplexer with high-quality factor based on nano-ring resonator

In this paper, we first present the design of a nano-ring resonator-based filter, in which scattering rods are used at the corners of the structure. By choosing a suitable radius for the dielectric rods in the nano-ring resonator, low channel spacing and high-quality factor parameters have been achieved at 1586.8 nm wavelength. Then, using this filter, a 2-channel demultiplexer is developed. In the proposed demultiplexer, two lattice constants are used: a(1) for the main structure and a(2) for the structure in the nano-ring resonator. The difference in the lattice constants results in an increase in the quality factor. Some of the advantages of this 2-channel demultiplexer include an average quality factor of 5443, average channel spacing of 0.35 nm, and central wavelengths of 1554.5 nm and 1557.1 nm, respectively, for the first and second channels. Moreover, the minimum and maximum inter-channel cross talks are - 17.63 dB and - 12.1 dB, respectively. Due to the 2.6 nm inter-channels spacing, this structure can be exploited in optical integrated circuits, WDM and DWDM systems.