Low loss titanium dioxide strip loaded waveguide on thin-film lithium niobate at 1550nm

This paper presents the use of TiO₂ as a strip loaded waveguide on thin-film lithium niobate (TFLN). The waveguides were fabricated by using an RF reactive sputtering deposition followed by a dielectric lift-off process. An additional layer of SiO2 was deposited as a cladding layer using a plasma-enhanced chemical vapor deposition (PECVD). To characterize this process, atomic-force-microscopy (AFM) and an ellipsometer were used. Lastly, a propagation loss of 1.26dB/cm at 1550nm was experimentally measured by Optical Backscatter reflectometry (OBR) and are presented in this paper.