Fabrication of low-loss photonic wires in silicon-on-insulator using hydrogen silsesquioxane electron-beam resist

Fully etched photonic wires in silicon-on-insulator have been fabricated and propagation loss values as low as 0.92 +/- 0.14 dB/cm have been obtained. Hydrogen silsesquioxane (HSQ) was used as an electron beam resist and as a direct mask in the dry-etch processing of the silicon core layer. The dimensional repeatability of the fabrication process was also estimated through measurements of the wavelength selection performance of nominally identical photonic wire Bragg gratings fabricated at intervals over a period of 37 days.