Implementing PCIe Gen5 on Linear Drive Optical Links

Copper cables have limited the propagation distance of PCIe signal due to data rate increasing. In this paper, we demonstrated a linear drive optical solution for PCIe Gen5 and developed a PCIe AIC (Add in Card) integrating a PCIe switch and QSFP (Quad Small Form-factor Pluggable) linear drive optics. A 30 meters Gen5 optical link was connected between two optical cards. Then signal quality and application performance were tested using SI (Signal Integrity) tool and NVMe-based FIO respectively. Results show that the signal integrity of linear driver optical link is qualified and meet the requirement of PCIe Gen5 practical application. And the optical link has a loss margin approximately 14 dB at the data rate of 32 GT/s. The linear drive technology is feasible to implement PCIe Gen5 signals over optical links.