Wavelength dependence of Pockels effect in strained silicon waveguides

We investigate the influence of the wavelength, within the 1.3 mu m-1.63 mu m range, on the second-order optical nonlinearity in silicon waveguides strained by a silicon nitride (Si3N4) overlayer. The effective second-order optical susceptibility <(chi((2))(xxy))over bar> evolutions have been determined for 3 different waveguide widths 385 nm, 435 nm and 465 nm and it showed higher values for longer wavelengths and narrower waveguides. For w(WG) = 385 nm and lambda = 1630 nm, we demonstrated <(chi((2))(xxy))over bar> as high as 336 +/- 30 pm/V. An explanation based on the strain distribution within the waveguide and its overlap with optical mode is then given to justify the obtained results. (C) 2014 Optical Society of America