The electro-optic Pockels effect may be generated in silicon photonics structures by breaking the crystal symmetry by means of a highly stressing cladding layer (typically silicon nitride, SiN) deposited on top of the silicon waveguide. In this work, the influence of the waveguide parameters on the strain distribution and its overlap with the optical mode to enhance the Pockels effect has been analyzed. The optimum waveguide structure have been designed based on the definition and quantification of a figure of merit. The fabrication of highly stressing SiN layers by PECVD has also been optimized to characterize the designed structures. The residual stress has been controlled during the growth process by analyzing the influence of the main deposition parameters. Therefore, two identical samples with low and high stress conditions were fabricated and electro-optically characterized to test the induced Pockels effect and the influence of carrier effects. Electro-optical modulation was only measured in the sample with the high stressing SiN layer that could be attributed to the Pockels effect. Nevertheless, the influence of carriers were also observed thus making necessary additional experiments to decouple both effects.

Date Published: 13 May 2016
PDF: 9 pages
Proc. SPIE 9891, Silicon Photonics and Photonic Integrated Circuits V, 98910E (13 May 2016); doi: 10.1117/12.2227606

Published in SPIE Proceedings Vol. 9891:
Silicon Photonics and Photonic Integrated Circuits V
Laurent Vivien; Lorenzo Pavesi; Stefano Pelli, Editor(s)