GeSi bandgap shift for tuneable high speed modulators

We report the results of absorption tunability of submicron rib waveguides based on Ge98.5%Si1.5% integrated into the Si platform. The transmission spectrum was characterised between 1520 nm and 1600 nm, before and after RTA annealing. The standard Tauc method was used to characterise the absorption profile of devices before and after thermal annealing. Material characterisation and simulations are also included to investigate the effect of RTA on the devices optical behaviour. A maximum blueshift of 38nm is reported using the proposed annealing technique which provides a cost-effective and efficient tool to tune the operational wavelength of devices such as electro-absorption modulators, realized on the SOI platform.