Nano-optical filter based on multicavity coupled photonic crystal ring resonator

In this present work, a narrow wavelength tunable filter is proposed for ultra-low crosstalk optical networking and sensing applications. The proposed optical device is realized by the novel structure of multicavity coupled photonic crystal ring resonator. The presented nanostructure contains ring resonator, waveguides and reflectors in a square lattice platform with ferroelectric materials arranged in the air medium. The wavelength tuning mechanism of the proposed device is based on effective refractive index modulation of barium titanate and it is employed to extremely shift the spectral position over a wide range of wavelength. For the computation of quality factor, output efficiency and sensitivity, Finite-Difference-Time-Domain (FDTD) simulations are performed. The designed tunable filter provides a high output efficiency of 100% and very narrow bandwidth of 0.6 nm with an ultra-footprint is 174.24 μm²; hence, it extraordinarily suitable for wavelength division based optical communication systems and nanosensing applications.