Local bandgap control of germanium by silicon nitride stressor.

We have proposed a new approach to tune the operation wavelength of Franz-Keldysh Ge electro-absorption modulation in Si photonics by controlling the local strain environment to cover the whole range of C + L bands (1.53 – 1.62 μm). The present paper shows a proof of strain-tuning modulator concept by the shift of the Ge absorption edge using SiNx stressor films and Franz-Keldysh effect in strain-controlled Ge.