Ion Implantation in Silicon for Trimming the Operating Wavelength of Ring Resonators

In recent years, we have presented results on the development of erasable gratings in silicon to facilitate wafer scale testing of photonics circuits via ion implantation of germanium. Similar technology can be employed to control the operating wavelength of ring resonators, which is very sensitive to fabrication imperfections. Ion implantation into silicon causes radiation damage resulting in a refractive index increase, and can therefore, form the basis of multiple optical devices. In this paper, we discuss design, modeling, and fabrication of ring resonators and their subsequent trimming using ion implantation of germanium into silicon, followed by either rapid thermal annealing or localized laser annealing. The results confirm the ability to permanently tune the position of the resonant wavelength to any point inside the free spectral range of the ring resonator, thus, greatly reducing the amount of power required for active tuning of these devices.