Simple description of laterally resonant, distributed-feedback-like modes of arrays of antiguides

Abstract

The Bloch-function method is used to provide a simple, yet accurate treatment of the leaky modes of infinite-extent antiguided arrays. Laterally resonant modes of infinite arrays are described for the first time. Bloch-function solutions for infinite arrays are used to explain key characteristics of the modes of finite-extent antiguided arrays. It is found that the resonant modes of antiguided arrays satisfy the second-order lateral Bragg condition, and consequently are analogous to the modes of second-order distributed-feedback (DFB) lasers. In effect, the resonant-optical-waveguide (ROW) array is a second-order lateral DFB structure with the radiative component along the longitudinal device axis, and zero stopband.