We have experimentally and theoretically demonstrated plasmonic couplers based on metal nanoparticles film (metal islands) deposited upon the optical dielectric waveguide. These nanoparticles forward scatter radiation into the optical waveguide that would otherwise be reflected and transmitted. Design, fabrication and optimisation of the plasmonic silver islands and tantalum pentoxide waveguide are reported. Broadband characteristics of light transmission showing plasmons excitation have been measured and in good agreement with simulated results from 400 nm to 800 nm. Coupling spectrum up to 15% is measured for the plasmonic coupler and in good agreement with the simulated results.