Millimeter-Long Silicon Photonic Antenna for Optical Phased Arrays at 2-μm Wavelength Band

Silicon photonic optical phased arrays are promising solutions for solid-state LIDAR. But the nonlinear absorption significantly saturates power in waveguides at 1.5-μm wavelengths. Besides, high refractive index contrast of silicon grating exhibits a strong diffraction strength antenna, which results limited aperture device. These ultimately place limit on detection accuracy and reach. Here, shallow etched two-dimensional subwavelength structure is proposed to improve efficiency waveguide antenna. A reduction achieved via nanohole instead conventional lines. Thus, millimeter-long antenna demonstrated with peak 71%. The far-field diffracted beam width 0.035° vertical field-of-view 17.5° within 100 nm wavelengths range from 1.95 μm 2.05 μm. operation 2-μm waveband also guarantees better eye-safety reduces compared band.