Loss reduction in silicon nanophotonic waveguide micro-bends through etch profile improvement

► Micro-bend of Si photonic wire waveguide is key for compact photonic circuits. ► Power losses in the bend waveguides are undesirable for many applications. ► Polarization cross-talk between TE-TM modes is one of the causes of loss. ► We show that bend loss can be reduced by 25% by improving the waveguide profile. ► We provide detailed fabrication technology behind this improvement.