Propagation Losses in Curved Integrated Optical Waveguides Based on Oxidized Porous Silicon

Abstract

The propagation losses are evaluated for the first time in curved integrated (buried) optical waveguides (WGs) based on oxidized porous silicon. In the visible red range, the losses decrease from 20 to 5 dB per 90 degrees bending (for about 0.4 dB/cm loss in the straight WG) when the WG curvature radius increases from 125 to 2500 mu m. The main component of the total bending losses in WGs is related to the coupling loss on the passage from straight to curved WG parts. Additional losses are introduced by the regions of incompletely oxidized porous silicon on the walls of curved WGs.