Modulation doped SiGe-Si MQW for low-voltage high-speed modulators at 1.3 mu m

We propose a new type of light modulator at 1.3 and 1.55 mu m using a delta -modulation-doped SiGe-Si multiple-quantum-well structure (delta-MDMQW) int egrated in a low-loss silicon-on-insulator (SOI) waveguide, The structure i s embedded in the intrinsic region of a vertical p-i-n diode realized on SO I substrate. We present theoretical calculation of the effective index modu lation determined by the variation of the confined hole concentration with an applied external field, A practical device is proposed and a calculation of optical modulation efficiency is presented, Estimation of on-off switch ing time based on evaluation of characteristic time of emission from locali zed levels in quantum wells and RC characteristics of the device are presen ted. This device presents the advantage of a broad optical bandwidth in comparis on to the modulators based on quantum-confined Stark effect, low insertion loss, high-speed (above 1 GHz), and full compatibility with silicon technol ogy.