FDTD simulation of amorphous silicon waveguides for microphotonics applications

A. Fantoni, P. Lourenço, P. Pinho, M. Vieira

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

5 Citations (Scopus)


In this work we correlate the dimension of the waveguide with small variations of the refractive index of the material used for the waveguide core. We calculate the effective modal refractive index for different dimensions of the waveguide and with slightly variation of the refractive index of the core material. These results are used as an input for a set of Finite Difference Time Domain simulation, directed to study the characteristics of amorphous silicon waveguides embedded in a SiO2 cladding. The study considers simple linear waveguides with rectangular section for studying the modal attenuation expected at different wavelengths. Transmission efficiency is determined analyzing the decay of the light power along the waveguides. As far as near infrared wavelengths are considered, a-Si:H shows a behavior highly dependent on the light wavelength and its extinction coefficient rapidly increases as operating frequency goes into visible spectrum range. The simulation results show that amorphous silicon can be considered a good candidate for waveguide material core whenever the waveguide length is as short as a few centimeters. The maximum transmission length is highly affected by the a-Si:H defect density, the mid-gap density of states and by the waveguide section area. The simulation results address a minimum requirement of 300nm×400nm waveguide section in order to keep attenuation below 1 dB cm-1.

Original languageEnglish
Title of host publicationIntegrated Optics
Subtitle of host publicationPhysics and Simulations III
PublisherSpie -- the Int Soc for Optical Engineering
ISBN (Electronic)978-1-5106-0985-3, 978-1-5106-0986-0
Publication statusPublished - 1 Jan 2017
EventIntegrated Optics: Physics and Simulations III 2017 - Prague, Czech Republic
Duration: 24 Apr 201725 Apr 2017


ConferenceIntegrated Optics: Physics and Simulations III 2017
Country/TerritoryCzech Republic


  • Amorphous Silicon
  • FDTD Simulation
  • waveguides


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