Sputter-deposited aluminium oxide as a waveguide platform for UV photonics

To overcome the increased absorption of commercially available waveguide platforms for UV wavelengths, Al2O3 has been suggested due to its low losses below 450 nm. In this work, we demonstrate Al2O3 waveguides fabricated via reactive sputtering, electron beam lithography and dry etching with losses as low as 2.3 dB/cm at 369 nm. A variety of building blocks required for typical photonic devices are realized using the process which shows promise as a waveguide platform for applications that require UV wavelengths.