Transversal symmetry breaking in novel photonic crystal waveguide: innovative manner to master defect band dispersion relation

We present a novel Photonic Crystal Slab (PhC) fabricated in Silicon (Si) with pattern edge along <11-2> direction. Such a design enabled a dry and wet etching processes combination to atomically flatten the sidewall surface defined by Si[111]. Moreover, a new method to tailor the relation dispersion of line defect PhC waveguide (W1) using this structure is introduced. By mismatching the upper and lower part of the waveguide in the propagation direction, FDTD simulations demonstrate a net shift of the Cut-Off wavelength from 1605nm to 1742nm for a mismatch of zero and half of the lattice constant of the crystal a, respectively. We discuss both use of this new PhC for repeatable photonic device on-chip integration and the benefit of this new waveguide design method to engineer large bandwidth mode