Photonic crystal waveguide intersection design based on Maxwell’s fish-eye lens

• Published in: Photonics and nanostructures 2018-09, Vol.31, p.154-159
• Main Authors: Gilarlue, M.M., Badri, S. Hadi, Rasooli Saghai, H., Nourinia, J., Ghobadi, Ch
• Format: Article
• Language: English
• Subjects: Bends; C band; Cables; Computer simulation; Crosstalk; Crystal lattices; Fisheye views; Footprints; Graded photonic crystal; Gradient index lens; Insertion loss; Integrated circuits; Intersections; Lattice parameters; Lenses; Maxwell’s fish-eye lens; Metamaterials; Nanostructured materials; Optical communication; Photonic crystals; Photonics; Waveguide intersection; Waveguides
• ISSN: 1569-4410; 1569-4429
• DOI: 10.1016/j.photonics.2018.08.001

•Maxwell’s fish-eye lens can be used as a multiband waveguide crossing medium.•Waveguide bends are needed in previous designs of intersection to adjust the crossing angle of waveguides.•Maxwell’s fish-eye lens is relatively insensitive to the angle of intersection so there is no need to design waveguide bends.•Waveguide intersection based on Maxwell’s fish-eye lens is implemented with graded photonic crystal and it is optimized to cover the entire C-band of optical communication. The number of waveguides crossing an intersection increases with the development of complex photonic integrated circuits. Numerical simulations are presented to demonstrate that Maxwell’s fish-eye (MFE) lens can be used as a multiband crossing medium. In previous designs of waveguide intersection, bends are needed before and after the intersection to adjust the crossing angle resulting in a larger footprint. The presented design incorporates the waveguide bends into the intersection which saves footprint. In this paper, 4 × 4 and 6 × 6 intersections based on ideal and graded photonic crystal (GPC) MFE lenses are investigated, where 4 and 6 waveguides intersect, respectively. The intersection based on ideal MFE lens partially covers the O, E, S, C, L, and U bands of optical communication, while the intersection based on GPC-MFE lens is optimized to cover the entire C-band. For 4 × 4 and 6 × 6 intersections based on GPC-MFE lens, crosstalk levels are below -24 dB and -18 dB, and the average insertion losses are 0.60 dB and 0.85 dB in the C-band with lenses’ radii of 7×a and 10×a, respectively, where a is the lattice constant of the photonic crystal.