An all-silicon channel waveguide fabricated using direct proton beam writing

Abstract

We report a novel technique for the fabrication of an all-silicon channel waveguide using direct proton beam writing and subsequent electrochemical etching. A focused beam of high energy protons is used to selectively inhibit porous silicon formation in the irradiated regions. By over-etching beyond the ion range, the irradiated region becomes surrounded by porous silicon cladding. Waveguide characterization carried out at 1550 nm on the proton irradiated waveguide shows that the propagation losses improve significantly from 20±2 dB/cm to 9±2 dB/cm after vacuum annealing at 800°C for 1 hour.