Analysis of Charge Distribution for Si Photonic Rib-type Waveguide

This paper provides the simulation of behaviour of the charge distribution for rib-waveguide in which fabrication is done by using silicon-on-insulator (SOI). An SOI substrate is used in this paper due to its high refractive index contrast in which enables a tight confinement of light in the channel or waveguide. In this paper, we determined and analysed the charge distribution for P-I-N rib waveguide by using free carrier-injection effect via change in electrical voltage. In carrier injection, the PIN waveguide is connected to the voltage supply forward-biased in which the p-doped (hole) region is on the positive terminal and n-doped (electron) region is on the negative terminal. For the examination of electron distribution as a function of applied bias, the drain bias voltage is varied from 0 V to 1.2 V in the interval of 0.2 V. Through our drain bias analysis, it is deduced that the n-doped region will get attracted to the p-doped region until PIN region is completely n-doped region. Therefore, there will be changes in refractive index in the core waveguide due to the diffusion of free charges. This changes in refractive index will eventually make our device tuneable.