Elsheikh Omar E, Swillam Mohamed A
Nanophotonics Research Laboratory, Department of Physics, The American University in Cairo, New Cairo Avenue, 11835, Cairo Governorate, Egypt.
Sci Rep. 2024 Feb 15;14(1):3780. doi: 10.1038/s41598-024-54016-w.
In the need for a more compact and efficient optical phased array with a wide steering beam for LIDAR applications, a wide steering array with high resolution is desirable. However, in the published work, a trade-off is often made for one over another. Apodized grating antennas have shown good efficiency with a compact size and wide beam profile, which improve optical phased array beam steering capability and are also compatible with the CMOS silicon photonics process. A promising studies shows enhancement in steering range with good resolution utilizing a non-uniform optical phased array. In this work, we present two highly efficient optical antennas with 94% and 93.5% upward power at the center frequency for the first and second antenna respectively, exceeding state-of-the-artwork to the best of our knowledge, and wide full-width half maximum of 8.88° x 78.05° and 7.53° x 69.85° in elevation and azimuthal planes, respectively. Both antennas provide a broad bandwidth across the 1400-1700 nm wavelength range with more than 80% efficiency in the S, C, and L bands. To overcome the limited scan ranges and small aperture size, a two-dimensional non-uniform array of 10 × 10 elements is utilized to increase the beam steering capability. A genetic algorithm is used to optimize the position of array elements, resulting in an aliasing-free array with a wide steering range of 160° with beam width 0.5° and consistent -11 dB maximum side lobe level across the steering range.
在激光雷达应用中，需要一种更紧凑、高效且具有宽波束转向功能的光学相控阵，因此高分辨率的宽波束转向阵列是理想之选。然而，在已发表的研究中，常常需要在两者之间进行权衡。切趾光栅天线已展现出良好的效率，尺寸紧凑且波束轮廓宽，这提高了光学相控阵的波束转向能力，并且还与CMOS硅光子学工艺兼容。一项有前景的研究表明，利用非均匀光学相控阵可在提高分辨率的同时增加转向范围。在这项工作中，我们展示了两种高效光学天线，第一天线和第二天线在中心频率处的向上功率分别为94%和93.5%，据我们所知，这超过了现有技术水平，并且在仰角和方位平面上的半高全宽分别为8.88°×78.05°和7.53°×69.85°。这两种天线在1400 - 1700 nm波长范围内都具有较宽的带宽，在S、C和L波段的效率均超过80%。为了克服扫描范围有限和孔径尺寸小的问题，采用了一个10×10元素的二维非均匀阵列来提高波束转向能力。使用遗传算法优化阵列元素的位置，得到了一个无混叠阵列，其转向范围宽达160°，波束宽度为0.5°，并且在整个转向范围内最大旁瓣电平一致，为 - 11 dB。
