The design we describe in this work consists of two sections with the cross-section of Fig. \ref{908186}a: 1) a traditional straight waveguide NLO section; and 2) several iterations of a straight waveguide NLO section plus a taper plus a 180^o bend, as in Fig. \ref{908186}b, to fold the device into a compact footprint and reduce the poling length significantly. Because of the high index of SiC, tight bends can be made in the SiC layer to keep the length of the device short without reducing the total nonlinear interaction length.

As poling length decreases, poling domain width increases based on the number of bends in the device. The design described here has a width of approximately 600 \(\mu\)m, though wider or narrower folded structures can be designed. This distance is comparable to the poling width of bulk LN devices, which are typically z-cut and poled through the substrate.