Hybrid integration of conventional waveguide and photonic crystal structures

We propose the hybrid integration of conventional index-guided waveguides (CWGs) and photonic crystal (PhC) regions of very limited spatial extent as a promising path toward large-scale planar lightwave circuit (PLC) integration. In CWG/PhC structures the PhC regions do not perform the function of waveguiding, but instead augment the CWGs to permit a drastic reduction in the size of photonic components. For single mode waveguides with a refractive index contrast of only 2.3%, simulation results show a 90 degree bend with 98.7% efficiency, a compact beamsplitter with 99.4% total efficiency, and a planar Mach-Zender interferometer (MZI) with 97.8% efficiency. The MZI occupies an area of only 18microm m x 18 microm.