One of the major challenges in integrated silicon photonics is the light coupling into and out of photonic circuits. Prism coupling, among waveguide coupling methods in the silicon photonics is a rather complex and costly one mostly due to the requirement of a prism with index of refraction higher than that of the effective index of the propagating mode in the waveguide. Surface plasmon polariton (SPP) allows the deployment of a fused silica prism instead of the high index prism, as indicated by our simulation using Lumerical FDTD software and Otto configuration of the SPP excitation scheme. Using the dispersion diagram the surface plasmon angle is determined to be 44◦ for the TM-mode of the incident beam. This is followed by examining the relevant parameters affecting the light coupling efficiency to a silicon waveguide of input dimensions of 220 750 nm. In Lumerical FDTD solver, two-dimensional simulation of plane waves of p-polarization enters the optical system at surface plasmon angle. This model reveals a coupling efficiency of 54% which at the very least is better than that of traditional prism coupling methods. For fabrication purposes, we could impose geometrical constraints on airgap height, making it a function of the waveguide and metal (silver in this case) strip thickness. Furthermore, we will show and discuss the effect of choice of the thickness for the Si waveguide, airgap, and silver layer on coupling efficiency from our mathematical model and Lumerical FDTD simulations.