$48\times10$ -Gb/s Cost-Effective FPC-Based On-Board Optical Transmitter and Receiver

In this paper, we demonstrate a low-cost, 48-channel, high-speed, flexible printed circuit (FPC)-based interconnect packaging concept for on-board optical modules. Due to the good high-speed performance and low cost, the FPC board is used as the base carrier for both transmitter and receiver modules. The on-board transmitter and receiver are based on a commercial 1-mm-pitch ISI HoLi pin grid array connector. The size of each module is only 31.5 <inline-formula> <tex-math notation="LaTeX">$\text {mm} \times 31.5$ </tex-math></inline-formula> mm and offers a state-of-art bandwidth density of 0.483 Gb/s/mm² by using a compact design. Investigation of RF signal propagation on the FPC is carried out for design validation at 10 Gb/s and, in order to further explore the potential of the suggested platform, differential pairs are simulated up to 30 GHz. The low-cost packaging approach requires only several flip-chip bonding steps using industry-standard solder reflow and ultrasonic bonding processes. An <inline-formula> <tex-math notation="LaTeX">$8 \times 12$ </tex-math></inline-formula>-channel optical straight lens connector is used to couple the light from the optics into two 48-fiber multi-fiber push on connectors with <inline-formula> <tex-math notation="LaTeX">$8 \times 12$ </tex-math></inline-formula>-channel MT ferrules. The fully assembled transmitter and receiver are tested at 10 Gb/s demonstrating error-free operation with sensitivities comparable with those of commercial devices. Bit error rates for all 96 channels as well as representative eye diagrams at 10 Gb/s are reported.