Silicon photonics systems integrate photonic components such as optical waveguides, coupler, resonator, etc. along with electronic components on the same silicon chip to realize high-bandwidth, high-density, and low-power communication. This tutorial provides an overview on common photonic devices such as microring modulator, Mach-Zehnder modulator, electro-absorption modulator, etc, and demonstrates how to model various wavelength-division multiplexing (WDM) systems tightly interacting with analog or digital electronic components and simulate them efficiently in SystemVerilog/XMODEL.