Time resolved electro-optic measurements in strained silicon racetrack resonators

In this paper, we report on time resolved electro-optic measurements in strained silicon resonators. Strain is induced by applying a mechanical deformation to the device. It is demonstrated that the linear electro-optic effect vanishes when the applied voltage modulation varies much faster than the free carrier lifetime, and that this occurs independently on the level of the applied stress. This demonstrates that, at frequencies which lie below the free carrier recombination rate, the electro-optic modulation is caused by plasma carrier dispersion. After normalizing out free carrier effects, it is found an upper limit of χ
⁽²⁾
= (8 ± 3) pm/V to the value of the strain induced χ
_eff,zzz
⁽²⁾
tensor component. This is an order of magnitude lower than the previously reported values for static electro-optic measurements.