Multilayered Maxwell's fisheye lens as waveguide crossing
Abstract
The Maxwell's fisheye (MFE) lens, due to its focusing properties, is an interesting candidate for implementing the crossing of multiple waveguides. The MFE lens is implemented by two different structures: concentric cylindrical multilayer and radially diverging gourd-shaped rods. Realization of the refractive index profile of the lens is achieved by controlling the thickness ratio of the alternating Si and SiO2 layers determined by effective medium theory. Both structures are optimized to cover the entire C-band in the single mode implementation. The transmission efficiency of the ring-based structure is superior to the radial-based implementation, however, the radial-based structure almost covers the entire U-band as well. Other communication bands are partially covered in both cases. Full-wave simulations prove that the performance of multimode waveguide crossing based on the MFE lens with a radius of 2 . 32 μm is promising with the average insertion loss of 0.17 dB and crosstalk levels below -24.2 dB in the C-band for TM0 and TM1 modes. The multimode intersection almost covers the entire C, L, and U bands of optical communication.
- Publication:
-
Optics Communications
- Pub Date:
- March 2019
- DOI:
- 10.1016/j.optcom.2018.11.057
- arXiv:
- arXiv:1812.00184
- Bibcode:
- 2019OptCo.435..385G
- Keywords:
-
- Photonic crystal;
- Multimode waveguide crossing;
- Maxwell's fisheye lens;
- Multilayer metamaterial;
- Gradient index lens;
- Effective medium theory;
- Physics - Optics
- E-Print:
- This is the preprint of the accepted manuscript. https://doi.org/10.1016/j.optcom.2018.11.057