Low loss intersection of Si photonic wire waveguides

We fabricated a low loss elliptical intersection of Si photonic wire waveguides on a silicon-on-insulator substrate. An insertion loss of less than 0.1 dB was achieved at a wavelength of 1.55 mum. The experimental loss characteristic closely agreed with the theoretical one. We also used this intersection as a suspension of an air-bridge-type waveguide and evaluated a low loss characteristic similar to that mentioned above.