Honeycomb Photonic Crystal Waveguides in a Suspended Silicon Slab

We report experimental evidence of light guiding at telecommunication wavelengths along line-defect honeycomb-lattice photonic crystal waveguides created in suspended silicon slabs. Numerical results show that the guided bands correspond to modes below the cladding light line so they are inherently lossless, although the measurements show quite high losses owing to fabrication imperfections. Honeycomb photonic crystals are a suitable platform for confining light and sound in nanoscale waveguides.