Design and analysis of a wavelength-sized Si disk resonator based temperature tunable beam splitter

Abstract The resonance of a wavelength-sized Si disk is used to design a tunable beam splitter with two separated orthogonal bus waveguides using the finite-difference time-domain method. The splitting ratio at the designed operating wavelength decreases from 2.906 to 0.052 with the increases in the temperature from 260 K to 340 K. The time-dependent field distributions show that the large range of splitting ratio is due to the suppression of an antisymmetric-like transverse mode in the coupling zone. The proposed structure can be used in various applications based on silicon photonic integrated circuits, such as optical neural network computing, optical quantum computing, and sensors.