Abstract
In this paper, we designed a 2×2 Mach-Zehnder(MZI) thermooptic switch based on multimode interference (MMI) couplers in silica-on-silicon. Issues concerning the influence of a number of design parameters for a 2×2 multimode interference coupler are discussed. The beam-propagation method (BPM) was used to demonstrate the feasibility of the proposed design of compact MMI coupler. P- doped silica films were deposited on Si substrates using a Plasma-Enhanced Chemical Vapor Deposition system. We successfully used reactive ion etching (RIE) to fabricate a low loss straight waveguide with smooth sidewall. A resistive material such as Aluminum was used as heating element. The silica-on-silicon technology with surface micromachining revealed an optimal design of a low power compact thermooptic switch