Microphotonics devices based on silicon microfabrication technology

TLDR

Si wire waveguides enable compact, high‑density optical circuits through strong light confinement, but suffer from significant connection and propagation losses. The study reports progress in developing an Si wire waveguiding system for microphotonics devices. The authors addressed losses by implementing a spot‑size converter and refining microfabrication, enabling fabrication of complex devices such as ring resonators and lattice filters. The optimized waveguides achieved propagation losses of 2.8 dB/cm and coupling losses of 0.5 dB per connection, and the fabricated devices—such as ring resonators and lattice filters—showed excellent performance, highlighting the potential of Si wire waveguides for nonlinear optics.

Abstract

This work presents our recent progress in the development of an Si wire waveguiding system for microphotonics devices. The Si wire waveguide promises size reduction and high-density integration of optical circuits due to its strong light confinement. However, large connection and propagation losses had been serious problems. We solved these problems by using a spot-size converter and improving the microfabrication technology. As a result, propagation losses as low as 2.8 dB/cm for a 400/spl times/200 nm waveguide and a coupling loss of 0.5 dB per connection were obtained. As we have the technologies for the fabrication of complex, practical optical devices using Si wire waveguides, we used them to make microphotonics devices, such as a ring resonator and lattice filter. The devices we made exhibit excellent characteristics because of the microfabrication with the precision of a few nanometers. We have also demonstrated that Si wire waveguides have great potential for use in nonlinear optical devices.