We report on fabrication of low loss single mode waveguides on lithium niobate on insulator (LNOI) cladded by a layer of SiO₂. Our technique, termed photolithography assisted chemo-mechanical etching (PLACE), includes (1) deposition of a thin layer of chromium (Cr) with a thickness of 400 nm on the surface of the LNOI by magnetron sputtering, (2) patterning of Cr film using femtosecond laser ablation, (3) etching of the LNOI layer by chemo-mechanical polishing (CMP), (4) removal of the Cr mask left on the surface of LNOI by chemical wet etching, (5) deposition of silicon dioxide on the LNOI waveguide to form the cladding layer by plasma enhanced chemical vapor deposition (PECVD). Fundamental building blocks for photonic integration, such as waveguide tapers and multi-mode interference (MMI) couplers and coil-shaped delay lines, are fabricated for boosting the coupling efficiency, beamsplitting and propagation loss measurement. The evolution of the spot from a circular spot with a diameter of ~1 μm to a highly elliptical spot with a transverse diameter of ~5 μm is observed from the output ports of the waveguide tapers with different taper lengths. The high-index-contrast single mode waveguide is measured to have a propagation loss of 0.130 ± 0.008 dB/cm by constructing a photonic circuit which consists of three electro-optically tunable cascaded Mach–Zehnder interferometers (MZIs) and two delay lines with different lengths.