Narrow beam and low-sidelobe electro-optic beam steering on thin-film lithium niobate optical phased array
薄膜铌酸锂光学相控阵上的窄波束和低旁瓣电光波束控制
薄膜リチウムニオブタート光位相配列における狭角ビームと低サイドローブの電気光学ビーム指向性制御
박막 리튬 나이오베이트 광 위상 배열에서 좁은 빔과 낮은 사이드로브 전기-광학 빔 조향
Piloteo electro-óptico de haz estrecho y de lóbulos laterales bajos en matriz de fase óptica de niobato de litio en película delgada
Dirigeable optoélectrique à faisceau étroit et faible lobe latéral sur réseau de phase optique à couche mince de niobate de lithium
Узкий луч и низко-боковой электрооптический наведение луча на тонкопленочной литиево-никобатной оптической фазированной решетке
Yang Li 黎洋 ¹ ², Shiyao Deng 邓世耀 ¹ ², Xiao Ma 马骁 ¹ ², Ziliang Fang 方子良 ¹ ², Shufeng Li 李姝锋 ¹ ², Weikang Xu 许伟康 ¹ ², Fangheng Fu 符方恒 ¹, Xu Ouyang 欧阳旭 ¹, Yuming Wei 韦玉明 ², Tiefeng Yang 杨铁锋 ¹, Heyuan Guan 关贺元 ², Huihui Lu 卢惠辉 ¹ ²
¹ Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Jinan University, Guangzhou 510632, China
中国 广州 暨南大学 广东省光纤传感与通信技术重点实验室
² International Cooperation Joint Laboratory for Optoelectronic Hybrid Integrated Circuits, Jinan University, Guangzhou 510632, China
中国 广州 暨南大学 教育部光电混合集成电路国际合作联合实验室
Optical beam steering has become indispensable in free-space optical communications, light detection and ranging (LiDAR), mapping, and projection. Optical phased array (OPA) leads this field as versatile and miniaturized platform to this end, yet conventional versions still suffer from a narrow steering field of view, insufficient sidelobe suppression, and limited angular resolution in electro-optic (EO) beam steering.
Thin-film lithium niobate (LN), with its strong EO effect, offers a powerful integrated-photonics platform to overcome these limitations. Here we present a two-dimensional (2D) EO-steered OPA based on a non-uniformly spaced X-cut thin-film LN ridge-waveguide array. A superlattice ridge design suppresses optical crosstalk to
20 dB, enabling low-sidelobe far-field radiation. Using particle swarm optimization method, we transform a uniformly spaced waveguide array into an optimized non-uniform design, largely improving angular resolution while maintaining sidelobe suppression.
When combined with a single-radiating trapezoidal end-fire emitter incorporating an etched grating, the device produces a main-lobe beam with fine width of 0.99°×0.63° from an aperture of only 140 μm×250 μm, achieving a wide 2D steering range of 47°×9.36° with a 20 dB sidelobe-suppression ratio. These results highlight thin-film LN OPA as a compelling route toward ultra-compact, high-performance high-speed EO beam-steering modules and optical free-space modulators.
