Low-Loss Photonic Integrated Elements Based on Bound Bloch Surface Wave in the Continuum

A Bloch surface wave (BSW) confined at the surface of a truncated dielectric multilayer is a low-loss platform for chip-scale photonic integration. The guided BSW in a dielectric ridge is confined by the photonic band gap vertically, yet couples into the continuum modes of the multilayered substrate horizontally. We demonstrate that a low-loss BSW waveguide can be realized with the quasibound BSW modes in the continuum by engineering the geometric parameters, due to the destructive interference of multiple leakage channels in the multilayered substrate. In addition, a high-Q BSW resonator is obtained by optimizing the geometric parameter of the multilayered substrate, which provides an alternative way to realize ultrasmall resonators with a high-Q factor. The photonic integrated circuits on a low-loss BSW platform can be utilized for optical communications, enhancing light-matter interactions, and nonlinear optical applications.