Ultra compact microring with resonator cavities inside

A novel add-drop filter based on microring embedded with several resonator cavities is proposed, and the effects of the numbers and radius of the cavities, as well as gaps between cavities and microring, on the performance of this filter are analyzed. The simulations show the spectrum of the filter could be improved when the resonance of cavities inside the microring are excited. This filter exhibits much smaller size and better spectrum than the conventional microring filter.