ULTRA-LONG SUBWAVELENGTH GRATING BASED OPTICAL ANTENNA FOR OPTICAL PHASED ARRAY

摘要

An ultra-long sub-wavelength grating as an optical antenna for optical phased arrays includes a top structure and a bottom structure which are vertically stacked. The bottom structure is made of a material with a refractive index lower than a refractive index of the top structure. The top structure is made of a material with a refractive index higher than that of the bottom structure. A strip waveguide is disposed in the middle of the top structure. subwavelength blocks are disposed periodically on two sides of the straight strip waveguides. The invention has the following beneficial effects. The structure could increase the effective length of the grating; uniform near field distribution can be achieved by controlling the positions of the subwavelength blocks. The structure is simpler with lower fabrication requirements and lower cost.