The propagation loss characteristics of silica-based optical waveguides with various bending curvatures fabricated on 5 inch Si wafers are investigated. Low loss waveguides more than 1 m long with a delta of 0.75% are successfully fabricated and the loss is found to be independent of the curvature radius over 5mm. A minimum loss of 3.5 dB/m at approximately 1.55 mum is obtained in a waveguide 1.6m long.