Monolithic carrier-beam steering with milliradian precision and single-voltage control

We describe what we believe to be a new class of monolithic beam steering systems. The device operates in the conventional 1550 nm communication band and can continuously steer over a 65.2° range with milliradian precision. The reported performance rests on two distinct advances, compatible with commercial foundry processes. The device core is a nonuniform, liquid-crystal-clad Si₃N₄ leaky grating, controlled by a single drive voltage over the entire operating range. The grating synthesis strategy uses a new etching alphabet to tailor equalized, out-of-plane radiation and achieve near-lossless operation. High core efficiency is paid for in terms of a small steering range of only 1.76°, which is expanded to 65.2°. We prove that conventional optics cannot extend the grating-native steering range without destroying the beam. A new approach incorporates a two-element metaoptic to expand the angular range by 37.9 times while simultaneously canceling aberrations and preserving beam quality across the full fan. The output beam width ranges from 3.37 to 4.26 milliradians, with a full-width-at-half-maximum median of 3.49 milliradians. The new beam-steering architecture guarantees 320 resolvable spots, accessible via continuous voltage mapping of 3.4-20 mV per milliradian of pointing. We detail an iterative design campaign comprising full-wave emitter synthesis, rigorous coupled-wave implementation to calibrate the absolute effective index to ±4.5 × 10^-5, and full-wave confirmation of the voltage transfer function at multiple bias points.