In this optical ring resonator, light propagates around the loop and remains in the waveguides. How? Due to a phenomenon called total internal reflection. This behavior is ideal for optical filters, notch filters, and other applications that require the blocking of light. To ensure that an optical ring resonator performs as expected, you can use wave optics modeling to evaluate the spectral properties. Get details in this blog post: https://buff.ly/2P9cFiX | COMSOL Multiphysics