Continuously phase-matched M-waveguides for second-order nonlinear upconversion

We present an analysis of an M-waveguide structure in lithium niobate that provides a new method for second-order nonlinear upconversion processes. M-waveguides can be designed to be continuously phase matched without the use of birefringence or quasi phase matching, and the output wave profile produced is single-lobed in the core region. M-waveguides provide a novel phase-matching technique and are ideal candidates for monolithically integrated circuits.