PCIe 4.0 Communication over Optical Fiber and TWINAX Cables

As cloud computing and deep learning accelerators drive faster advances in the PCIe roadmap, existing hardware designs cannot support the higher speed signals over the same distances. The PCIe 1.0 specification allowed signals to travel as much as 20 inches over traces in mainstream FR4 boards, even while passing through two connectors. In contrast, today’s quicker 16 GT/s PCIe 4.0 signals will peter out in under six inches and without going over any connectors.