Optical phased array (OPA) technology is considered a promising solution for solid-state beam steering to supersede the traditional mechanical beam steering. As a key component of the LIDAR system for long-range detection, OPAs featuring a wide steering angle and high resolution without beam aliasing are highly desired. However, a wide steering range requires a waveguide pitch less than half of the wavelength, which is easily subjected to cross talk. Besides, high resolution requires a large aperture, and it is normally achieved by a high count number of waveguides, which complicates the control system. To solve the mentioned issues, we design two high-performance 128-channel OPAs fabricated on a multilayered SiN-on-SOI platform. Attributed to the nonuniform antenna pitch, only 128 waveguides are used to achieve a 4 mm wide aperture. Besides, by virtue of innovative dual-level silicon nitride (${\mathrm{Si}}_3{\mathrm{N}}_4$) waveguide grating antennas, the fishbone antenna OPA achieves a $100°\times 19.4°$ field of view (FOV) with divergence of $0.021°\times 0.029°$, and the chain antenna OPA realizes a $140°\times 19.23°$ FOV with divergence of $0.021°\times 0.1°$. To our best knowledge, 140° is the widest lateral steering range in two-dimensional OPA, and 0.029° is the smallest longitudinal divergence. Finally, we embed the OPA into a frequency-modulated continuous-wave system to achieve 100 m distance measurement. The reflected signal from 100 m distance is well detected with 26 dBm input transmitter power, which proves that OPA serves as a promising candidate for transceiving optical signal in a LIDAR system.

中文翻译：

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宽转向角高分辨率光学相控阵

光学相控阵 (OPA) 技术被认为是取代传统机械光束转向的固态光束转向的有前途的解决方案。作为 LIDAR 系统远程检测的关键组件，具有宽转向角和高分辨率且无波束混叠的 OPA 是非常受欢迎的。然而，较宽的转向范围要求波导间距小于波长的一半，这很容易受到串扰。此外，高分辨率需要大孔径，并且通常通过大量波导来实现，这使控制系统复杂化。为了解决上述问题，我们设计了在多层 SiN-on-SOI 平台上制造的两个高性能 128 通道 OPA。由于天线间距不均匀，因此仅使用 128 个波导来实现 4 毫米宽的孔径。除了，${硅}_3{\mathrm{N}}_4$) 波导光栅天线，鱼骨天线 OPA 实现了 $100°\times 19.4°$ 具有发散度的视野 (FOV) $0.021°\times 0.029°$, 而链式天线 OPA 实现了 $140°\times 19.23°$ 具有发散度的 FOV $0.021°\times 0.1°$. 据我们所知，140° 是二维 OPA 中最宽的横向转向范围，0.029° 是最小的纵向发散。最后，我们将 OPA 嵌入到调频连续波系统中，以实现 100 m 的距离测量。使用 26 dBm 输入发射机功率可以很好地检测到来自 100 m 距离的反射信号，这证明 OPA 是 LIDAR 系统中收发光信号的有希望的候选者。