Enhanced coupling efficiency into the slow light photonic crystal waveguide using index matching layer

초록

This research is about the method to enhance coupling efficiency between the strip waveguide and the slow light photonic crystal waveguide. Because the slow light photonic crystal waveguide has a low group velocity, it provides unique functionalities for integrated photonics, e.g. optical buffers and devices that use optical nonlinear effect. However, an increase of the group index in the slow light photonic crystal waveguide lowers coupling efficiency because of increasingly large impedance mismatch. In this study we propose a method to design index matching layer at the interfaces between the strip waveguide and the slow light photonic crystal waveguide. The design parameters of the optimal index matching layer can be obtained from the antireflection coating theory and the finite-difference time-domain simulations.