We demonstrate good optical quality $\mathrm{Ti}{\mathrm{O}}_2$ thin films grown by atomic layer deposition at $120°\mathrm{C}$ . The optical properties were studied using spectroscopic ellipsometry and prism coupling methods. The refractive index was 2.27, and the slab waveguide propagation loss was less than $1\mathrm{dB}/\mathrm{cm}$ at $1.53\mathrm{\mu m}$ . A high quality resonant waveguide grating was fabricated using a thin $\mathrm{Ti}{\mathrm{O}}_2$ layer on top of a $\mathrm{Si}{\mathrm{O}}_2$ grating.