Insertion Loss and Misalignment Tolerance in Multimode Tapered Waveguide Bends

Abstract—Experimental measurements of laterally tapered mul-timode waveguide bends fabricated photolithographically on FR4 printed circuit board establish that the product of the mean inser-tion loss (in linear units) and the mean source misalignment toler-ance is a constant which depends only on the taper ratio TR (input width/output width) and not on the radius of curvature . The minimum loss of 0.78 dB occurs in the special case of TR , mm. Together, these form waveguide layout design rules for board-to-board and chip-to-chip optical interconnects. Index Terms—Multimode polymer waveguide, optical printed circuit board, spotsize converter, tapered waveguide bend. I