Numerical simulation of optical sensing by the far field pattern radiated by periodic grating strips over silica buffer on the silicon wire waveguide

Andrei Tsarev, Vittorio M.N. Passaro

Research output: Contribution to journalLetterpeer-review

Abstract

This paper presents results of numerical modeling of a modified design of an optical sensor based on segmented periodic silicon oxynitride (SiON) grating evanescently coupled with silicon wire. This segmented grating works as a leaky waveguide, which filters input power from a broadband optical source and radiates it as an outcoming optical beam with both a small wavelength band and a small beam divergence. The radiation angle strongly depends on the refractive index of the grating environment and provides sensor interrogation by measuring the far field pattern in the focal plane of the lens, which is placed near the sensor element. The device concept was verified by direct numerical modeling through the finite difference time domain (FDTD) method and provided moderate intrinsic limit of detection (iLOD) ~ 0.004 RIU with a possible iLOD ~ 0.001 RIU for 10 mm‐long structures.

Original languageEnglish
Article number5306
Pages (from-to)1-8
Number of pages8
JournalSensors (Switzerland)
Volume20
Issue number18
DOIs
Publication statusPublished - 2 Sep 2020

Keywords

  • Far field pattern
  • Finite difference time domain (FDTD) method
  • Numerical modeling
  • Optical sensors
  • Segmented grating
  • Silicon oxynitride (SiON)
  • Silicon wire
  • far field pattern
  • DESIGN
  • silicon oxynitride (SiON)
  • silicon wire
  • optical sensors
  • COUPLER
  • MICRORING RESONATOR
  • PHASE
  • EFFECTIVE-INDEX METHOD
  • finite difference time domain (FDTD) method
  • BIOSENSOR
  • segmented grating
  • numerical modeling

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