Efficient Line Beam Scanning Based on a Hybrid Optical Phased Array Rendering Flexible Field-of-Views

Abstract

Conventional OPAs incorporating a diffraction grating were mainly developed to achieve a two-dimensional spot beam-based scan, which inevitably requires a wide range of wavelength tuning, leading to unaffordable complexity and limited scanning speed. In this study, we demonstrate a hybrid OPA that capitalizes on a silicon nitride line beam emitter based on tapered waveguides array, which facilitates efficient line beam scanning exhibiting flexible vertical field-of-views (FOVs) at a wavelength of 1550 nm. The line beam is horizontally scanned by driving an array of hybrid-integrated thermo-optic polymer phase modulators. The vertical FOV can be flexibly adjusted by varying the tip widths of the tapers and thus the angular divergence of emitted beams, leading to flexible FOVs ranging from 30° × 14° to 30° × 47°. A lens module is particularly devised and tethered to the OPA, thereby further tailoring and amplifying the FOVs along vertical and horizontal directions. The proposed hybrid OPA in conjunction with a lens module was practically manufactured to efficiently substantiate desired line beam scanning, achieving FOVs ranging from 51° × 0.6° to 51° × 10.3°. The developed line-beam-based OPA is anticipated to play an integral role in embodying an advanced LiDAR system featuring fast beam scanning.