We report theoretical and experimental results for the wavelength and polarization selectivity of a fiber-to-planar waveguide coupler made of a side polished single mode fiber covered with a planer waveguide incorporating a thin metal film. A simple but exact approach to obtain the modal properties of multilayer planar waveguide with a thin metal film is described. The device was modeled into equivalent 1 dimensional structure and its behaviour was analyzed based on coupled mode theory. The effects of metal film thickness and refractive index of superstrate on the device properties were measured and explained.