Crossed polymer optical waveguide for optical printed circuit board

We propose to apply graded-index (GI) cores into crossed multimode waveguides. We already confirmed the strong optical confinement effect of GI cores, and thus, GI cores enable to decrease the light leakage at the crossed area, compared to the step-index (SI)-core crossed waveguides. In fact, we calculate the light propagation loss in crossed waveguides with SI and GI cores by developing a ray tracing simulation program. It is found that the GI core shows remarkably lower waveguide loss (0.19 dB for 50-perpendicular crosses) than those of SI core (3.7 dB for the same crossings).