Electrically-actuated cantilever for planar evanescent tuning of microring resonators in SOI platforms

A novel design for tuning the resonant frequency of optical microring resonators is proposed, based on side evanescent field perturbation using a MEMS cantilever. Both mechanical and optical properties of the cantilever, defined in the top silicon layer of a standard SOI stack, are evaluated numerically. The height of the suspended structure is controlled through electrostatic actuation. The presence of the cantilever in the near-field of the optical mode affects the effective refractive index, resulting in frequency tuning. Results show a tuning range of the resonant frequency of about 12 nm, around 1550 nm, which is suitable for WDM applications.