Compact mode-insensitive ring resonator based on SWG coupler and Euler bends

In this paper, we propose and demonstrate a mode insensitive micro-ring resonator which could process TE₀ and TE₁ modes simultaneously. The proposed device is composed of 90 ° modified Euler bend waveguide and deeply etched subwavelength grating (SWG) coupler. The curvature design of the Euler curve is smoother than that of the Bezier curve, thus reducing the size. The SWG waveguide can enhance the coupling effect by decreasing the refractive index difference between cladding and core compared to directional couplers and therefore it also reduces the size. Detail size of fabrication is performed, footprint is reduced by 46% to 170 μm. The proposed device could be utilized in advanced MDM transmission system.