O-Band GeSi Quantum-Confined Stark Effect Electro-Absorption Modulator Integrated in a 220nm Silicon Photonics Platform

We report on a waveguide-coupled quantum-confined Stark effect (QCSE) electro-absorption modulator integrated in a 220nm Si photonics platform and operating in 1335-1365nm wavelength range. The device is based on a strain-balanced GeSi quantum well/barrier stack grown on an ultra-thin strain-relaxed buffer. The stack is only 450nm thick, facilitating optical coupling to sub-micron Si waveguides. An extinction ratio up to 8dB is achieved in a 40μm long device for a 1 Vpp drive voltage, demonstrating the potential of this modulator for low-power optical interconnect applications.