A simple and cost-effective technology to integrate an optical waveguide into circuits in plastic board has been used to develop a 0.6 3 0.6 mm2 polymer waveguide in a plastic substrate. A simple direct coupling method was used to couple the light from a multimode optical fiber to the SU-8 waveguide core. The interconnect achieved 2.45 and 2.54 dB/cm propagation loss at 1550 nm and 1310 nm wavelength, respectively, for a polyvinyl chloride polymer cladding and 1.66 and 1.51 dB/cm at 1550 and 1310 nm wavelength, respectively, for polymethyl methacrylate polymer cladding.