Silicon micro ring modulators are critical components in optical on-chip communications. The performance of an interleaved p-n junction micro ring modulator using FDTD solutions has been characterized. In this paper, the model and simulation of a modulator utilizing an interleaved junction with a SiO(2)layer with a thickness of 10 mu m have been presented. It is demonstrated that a loss of 34.7 dB/cm occurs during transmission. The modulator operates at 1.55 mu m wavelength with a V pi L of 0.78 V-cm at a voltage of 1 V, which gives figure of merit.