Erasable diffractive grating couplers in silicon on insulator for wafer scale testing

R. Topley, G. Martinez-Jimenez, L. O'Faolain, N. Healy, S. Mailis, D. J. Thomson, F. Y. Gardes, A. C. Peacock, D. N.R. Payne, G. Z. Mashanovich, G. T. Reed

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

1 Citation (Scopus)


Test points are essential in allowing optical circuits on a wafer to be autonomously tested after selected manufacturing steps, hence allowing poor performance or device failures to be detected early and to be either repaired using direct write methods, or a cessation of further processing to reduce fabrication costs. Grating couplers are a commonly used method for efficiently coupling light from an optical fibre to a silicon waveguide. They are relatively easy to fabricate and they allow light to be coupled into/out from any location on the device without the need for polishing, making them good candidates for an optical test point. A fixed test point can be added for this purpose, although traditionally these grating devices are fabricated by etching the silicon waveguide, and hence this permanently adds loss and leads to a poor performing device when placed into use after testing. We demonstrate a similar device utilising a refractive index change induced by lattice disorder. Raman data collected suggests this lattice damage is reversible, allowing a laser to subsequently erase the grating coupler.

Original languageEnglish
Title of host publicationSilicon Photonics IX
ISBN (Print)9780819499035
Publication statusPublished - 2014
Externally publishedYes
EventSilicon Photonics IX - San Francisco, CA, United States
Duration: 3 Feb 20145 Feb 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSilicon Photonics IX
Country/TerritoryUnited States
CitySan Francisco, CA


  • Diffraction gratings
  • Grating couplers
  • Silicon photonics


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