Optical interconnection using fiber-embedded boards and connection blocks fabricated by a micro-grooving technique for fiber insertion

We fabricated fiber-embedded boards using a micro-grooving technique for optical interconnects. This approach is quite cost effective and fully compatible with conventional PCB processes. U-shaped grooves were formed on FR-4 plates using a 90° V-shaped diamond blade. Polyimide-coated glass fibers were inserted in the grooves followed by a conventional lamination process. The 12 fibers embedded in the board showed a good uniformity in their position with a fluctuation below ±8 µm. Optical connection blocks were also fabricated using fiber segments embedded in a grooved silicon wafer piece in order to couple the light between a transmitter/receiver module and a fiber-embedded board. 45° mirrors were formed at the end of the connection blocks by mechanical polishing. An optical link of 2.5 Gb s −1 signals with a high coupling efficiency was demonstrated through the fiber-embedded connection blocks and a board.