研究発表

We present on-board fabrications for densely-aligned graded-index (GI) multiple-core polymer optical waveguides utilizing soft-lithography or dispensers, in order to realize the board-level optical interconnections with these waveguides. We experimentally confirm that near parabolic refractive index profiles are formed in the cores of newly developed 20-cm long waveguides (40 um x 40 um size at 75-um pitch). We also use a copolymer for forming the GI profile, and then, confirm the high-temperature stability of the parabolic index profile compared to the one formed with a doped polymer. Finally, we discuss about the crosstalk property of the fabricated waveguides.

We newly develop W-shaped graded-index core polymer optical waveguide which performs high bandwidth and low crosstalk. Although this is capable of being used in high performance computers, we propose to clarify the inter-channel crosstalk results from mode conversion more significantly. In this paper, first we demonstrate the experiment results, and then we apply the ray-trace simulation to show the ray trajectories, length dependent near field patterns, and crosstalk values. Furthermore, we visually and numerically compare the performance between the conventional step-index and our graded-index type counterparts. These investigations prove that W-shaped and graded-index core waveguides have high potential to be used in high-speed optical interconnections.