Thermo-electro-optical analysis of an integrated waveguide-vanishing-based optical modulator

Silicon is the most widely used material in the microelectronics industry and it is becoming more widespread in integrated optic and opto-electronic fields. We present the thermo-electro-optical analysis of an integrated waveguide-vanishing-based optical modulator based on the free carrier dispersion effect. This particular structure allows one to obtain a planar device, with an easier CMOS compatible microelectronic integration. The implantation processes have been carefully tuned in order to get higher doping uniformity and a sharp profile. The process-flow is defined using the 2D process simulation software ATHENA ( SILVACO International). The 2D semiconductor device simulation package ATLAS ( SILVACO International) has been employed to analyse the coupled electro-thermal behaviour of our modulator in static and dynamic conditions. The electrical section of the modulation acts as a lateral p-i-n diode. The resulting channel waveguide shows single mode operation and propagation losses of about 10 dB cm(-1). The modulator optical behaviour is based on the vanishing of the lateral confinement in the rib region. Results show that an optical modulation depth close to 100% can be reached with a power expense of about 650 mW and an operation -3 dB bandwidth of about 25 MHz.