Loading...

Minimum length modulator design with a graphene-based plasmonic waveguide

Ghahri, M. R ; Sharif University of Technology

662 Viewed
  1. Type of Document: Article
  2. DOI: 10.1364/AO.56.004926
  3. Abstract:
  4. In this study, we simulated and analyzed a plasmonic waveguide modulator based on a single layer of graphene. It includes a graphene sheet, which sandwiches between two layers of silicon dioxide. Then, some gates are arranged on either side of the waveguide on a periodic structure. When an electric field is applied perpendicular to the waveguide plate, the Fermi level of graphene under the gates changes. Detailed analysis is performed by the method of lines based on Maxwell's equations along the propagation direction of the waveguide. Computation of the multi-gate device starts by examining the effect of the Fermi level. The transmission coefficient of the magnetic-field norms of the modulator is calculated by varying the parameters, such as Fermi level, length, gates number, and distance between the gates to achieve optimized design of the modulator device with very small dimensions. The results show that at higher Fermi levels, where the imaginary part of the effective index of the waveguide is close to zero, the reflection is dominant and absorption is low. Therefore, the modulator length becomes so long that it is more than one hundred nanometers. At lower Fermi levels, where the amount of the imaginary part of the effective index is significant, the absorption is dominant. At this range, a one-gate device is sufficient for modulation. Consequently, the designed minimum device length becomes equal to six nanometers for the ten-micrometer wavelength. Furthermore, the design is carried out in other wavelengths. © 2017 Optical Society of America
  5. Keywords:
  6. Electric fields ; Fermi level ; Graphene ; Light modulators ; Maxwell equations ; Optical waveguides ; Plasmons ; Waveguides ; Effective index ; Imaginary parts ; Method of lines ; Multigate devices ; Optimized designs ; Plasmonic waveguides ; Propagation direction ; Transmission coefficients ; Modulators
  7. Source: Applied Optics ; Volume 56, Issue 17 , 2017 , Pages 4926-4933 ; 1559128X (ISSN)
  8. URL: https://www.osapublishing.org/ao/abstract.cfm?uri=ao-56-17-4926