David Trop | Searcharxiv

arXiv2026

Dielectric-loaded guided-wave electro-optic modulator using bulk rubidium titanyl phosphate

Rubidium titanyl phosphate (RTP) is widely used in bulk Pockels cells because it combines a useful linear electro-optic response with low dielectric permittivity, high electrical resistivity, negligible piezoelectric ringing, and high optical-damage tolerance. Its use in integrated or guided-wave modulators has been limited by the absence of a mature thin-film RTP platform. Here we propose a dielectric-loaded guided-wave modulator in which a silicon nitride strip on an unetched bulk RTP crystal forms a near-surface optical mode that overlaps with side-electrode fields. The analysis focuses on full-vector optical modes, GSG electrostatic and RF response, tensor-aware electro-optic coupling, and device-level performance at 1064~nm.

physics.optics↗

arXiv2026

Numerical Investigation of a 3D End-Firing Antenna Array Based on Two-Photon Polymerization on Thin-Film Lithium Niobate for Optical Beam Steering

Optical phased arrays (OPAs) are key components for solid-state beam steering in emerging photonic technologies such as LiDAR, optical communication, and adaptive optics. However, conventional integrated OPA designs face trade-offs between bandwidth, steering range, and fabrication complexity. Here we designed and numerically analyzed a novel three-dimensional end-firing antenna array compatible with fabrication using two-photon polymerization (2PP) directly on a thin-film lithium niobate (TFLN) platform. By elevating the polymer antennas above the chip surface, the design enables two-dimensional beam steering while maintaining the broadband advantages of end-fire emission. Full-wave electromagnetic simulations demonstrate transmission efficiencies up to 89.5\% over the \SIrange{1.4}{1.6}{\micro\meter} wavelength range, achieving a field of view of \ang{24.9} $\times$ \ang{22.8} with beamwidths of approximately \ang{1.7}. The architecture's compatibility with electro-optic phase control and advanced array configurations suggests significant potential for high-speed, low-loss beam steering systems. This work establishes a foundation for scalable 3D photonic phased arrays that bridge integrated optics with free-space beam manipulation.

physics.optics↗