@article{wan2016rigorous,
  title={Rigorous coupled-wave analysis equivalent-index-slab method for analyzing 3D angular misalignment in interlayer grating couplers},
  author={Wan, Congshan and Gaylord, Thomas K and Bakir, Muhannad S},
  journal={Applied optics},
  volume={55},
  number={35},
  pages={10006--10015},
  year={2016},
  publisher={Optical Society of America}
}