Dual-function beam splitter of high contrast gratings* *Project supported by the Open Fund of the State Key Laboratory of Information Photonics and Optical Communication, Beijing University of Posts and Telecommunications, China (Grant No. IPOC2019A009) and the National Natural Science Foundation of China (Grant Nos. 61501214 and 61501213).

Abstract

We present the design and fabrication of a novel dual-function high contrast gratings that can be used as a polarization-selective beam splitter with transverse magnetic polarization, which performs two independent functions, i.e., reflection focusing and power equalization at a wavelength of 1550 nm. This dual-function grating profile is optimized by the rigorous coupled-wave analysis and the finite-element method. Simple analytical expressions of phase and modal guideline for the beam splitter design are given. The beam splitter based on the grating structure is experimentally studied at a distance of 160 μm from the reflection plane, the results are consistent with the theoretical results basically.