Wannier basis design and optimization of a photonic crystal waveguide crossing

We employ a novel platform for the realization of tunable photonic crystal (PC) circuits together with a Wannier basis modeling and optimization scheme in order to design a broad-band waveguide crossing. The superior performance characteristics of our design include a high bandwidth (2% of the center frequency) as well as low values for crosstalk (-40 dB) and reflection (-30 dB). In addition, we demonstrate the robustness of the device performance against fabrication disorder. Our novel design paradigm will enable efficient and ultracompact PC-based device designs with complex functionalities.