Polarization insensitivity induced for 1 × 9 splitter with T-type SiO2 grating ridge

Abstract

To reduce the polarization sensitivity, a T-type grating with the material SiO 2 is proposed on a reflective layer made of aluminum material. Based on structural parameters derived from rigorous coupled-wave analysis and simulated annealing, the described reflection beam splitter enables a nine-port separation under normal incidence. In addition, it demonstrates exceptional and uniform diffraction efficiency. For transverse electric polarization, the diffraction efficiencies of 0th, ±1st, ±2nd, ±3rd, and ±4th are 10.02%, 11.70%, 10.85%, 11.00%, and 10.03%, respectively. For transverse magnetic polarization, the diffraction efficiencies of 0th, ±1st, ±2nd, ±3rd, and ±4th are 12.54%, 10.13%, 9.51%, 10.46%, and 11.89%, respectively. The finite element technique is used to verify the diffraction efficiency values. In addition, a thorough analysis of the fabrication tolerance, wavelength bandwidth, and electromagnetic field dispersion is conducted. The outcome shows that the suggested grating structure has outstanding uniformity and efficiency, and these studies greatly enhance our knowledge of and progress toward the creation of the nine-port beam splitter. Consequently, there is a lot of room for the implementation of the suggested grating in multi-channel optical communication systems.