High-efficiency multi-port beam control device based on periodic nanodisk arrays

Abstract

In this article, a multi-port two-dimensional (2D) reflective grating by a nanodisk array is proposed, which can be used for high-efficiency four-port ((0, ±1) and (±1, 0) orders) and five-port ((0, 0), (0, ±1) and (±1, 0) orders) optical control at a communication wavelength. Finite element method provides fast and effective optimization and analysis of the proposed 2D grating, while the 3D finite-difference time-domain provides strong support for the data in this paper. The four-port grating beam splitter has an efficiency of nearly 24% for all main diffraction orders with uniformity and polarization-dependent losses (PDL) of 0.8% and 0.08 dB, respectively. Meanwhile, the five-port grating beam splitter achieves an efficiency of over 19% for each diffraction order and in excess of 96% overall, with a uniformity and PDL of 0.4% and 0.06 dB, respectively. In addition, the detailed analysis of bandwidth performance and manufacturing tolerances shows the advantages of the proposed 2D nano-grating in practical applications and manufacturing. These findings have positive implications for future research on 2D nano-gratings, and the proposed 2D nano-grating has promising applications in the fields of sensor networks, grating measurements, photonic crystals, etc.