Polymer-based silver stripe optical waveguides were developed for chip-to-chip optical interconnections, and their optical characteristics were investigated. The lowest propagation loss of 0.8 dB/cm was achieved with a 14-nm-thick 1.5-mu m-wide stripe, at a wavelength of 1.3 m. The 2.5-Gb/s optical signals were successfully transmitted via 10-cm-long silver stripe optical waveguides.