Schematic of the fabrication workflow for LTOI optical waveguides, including DLC hard-mask deposition by plasma-enhanced chemical vapour deposition (PECVD) from the methane precursor, DLC dry etching through oxygen plasma, and LiTaO 3 etching by argon ion-beam etching (IBE), followed by redeposition and mask removal. The layers are DLC (black), LiTaO 3 (light blue), SiO 2 (purple) and Si (grey). Spheres show C (black), O (red) and Ar + (green).
