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In Applied optics

We report a two-dimensional Si photonic optical phased array (OPA) optimized for a large optical aperture with a minimal number of antennas while maintaining single-lobe far field. The OPA chip has an optical aperture of ∼200µm by 150 µm comprising a 9×9 antenna array. The two-dimensional spacings between these antennas are much larger than the wavelength and are highly non-uniform optimized by the genetic deep learning algorithm. The phase of each antenna is independently tunable by a thermo-optical phase shifter. The experimental results validate the design and exhibit a 0.39×0.41 beamwidth within the 3 dB steering range of 14×11 limited by the numerical aperture of the far-field camera system. The method can be easily extended to a larger aperture for narrower beamwidth and wider steering range.

Xue Yulong, Zhang Qihao, Ren Yangming, Lei Yufang, Sun Xiaochen, Zhang Lingxuan