A numerical analysis of a refractive index sensor based on multimode interference (MMI) waveguide has been performed in this paper. The nonlinear refractive index of graphene in the proposed sensor was investigated by applying external electric field on the graphene cladding layer. The designed waveguide was constructed using silicon oxide (SiO₂) as substrate and silicon as a core while graphene is coated on top of the waveguide slab. The response of the sensor in the output power was examined and validated by changing liquid samples with different refractive index. The guided modes of the 1550 nm input plane source at the absence of external electric field were used as the initial reference point. It is found that there was a threshold magnitude of the field which makes graphene sensitive to the relative change in the refractive index of the solution. The output results showed a promising indication that this design is appropriate for environmental monitoring.

Date Published: 26 June 2017
PDF: 6 pages
Proc. SPIE 10329, Optical Measurement Systems for Industrial Inspection X, 103294G (26 June 2017); doi: 10.1117/12.2271400

Published in SPIE Proceedings Vol. 10329:
Optical Measurement Systems for Industrial Inspection X
Peter Lehmann; Wolfgang Osten; Armando Albertazzi Gonçalves Jr., Editor(s)