Pockels effect in strained silicon

Pedro Damas (1) , Xavier Le-Roux (1) , Mathias Berciano (1) , Delphine Marris-Morini (1) , Eric Cassan (1) , Laurent Vivien (1)

1 C2N - Centre de Nanosciences et de Nanotechnologies [Orsay]

Silicon photonics is being considered as the future photonic platform, mainly for the reduction of photonic system costs and the increase of the number of functionalities on the same integrated chip by combining photonics and electronics. However, silicon is a centrosymmetric crystal, which inhibits Pockels effect: a second order nonlinear effect which allows for light modulation at speeds that are not limited by carriers and driven at very low power consumption. Nevertheless, this limitation can be overcome by straining the crystal lattice and breaking the crystal symmetry of silicon. This crystal modification is achieved by depositing a SiN high-stress overlayer. Over the last few years, several researches have been performed exploring Pockels effect in strained silicon. In this work, we present recent developments on the subject taking into account parasitic effects including plasma dispersion effect and fixed charge effect under an electric field. We experimentally demonstrate Pockels effect in silicon waveguides strained by a SiN overlayer deposited by PECVD as a function of the wavelength and the waveguide width. Recent results on high-speed measurements have been performed to well dissociate Pockels effect and plasma dispersion effect.

Domaines: Optique / photonique; Matériaux; Micro et nanotechnologies/Microélectronique

Pedro Damas, Xavier Le-Roux, Mathias Berciano, Delphine Marris-Morini, Eric Cassan, et al.. Pockels effect in strained silicon. SPIE Photonics West, 2016, San Francisco, United States. ⟨hal-01527448⟩