Fujitsu Lights up PCI Express with Intel Silicon Photonics

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A PCI Express copper cable vs the MXC optical cable used by Intel's Silicon photonics technology. (Photo: Intel)

Intel and Fujitsu have demonstrated a new server using Intel silicon photonics technology in an Optical PCI Express (OPCIe) design, which allows the storage and networking to be disaggregated, or moved away from the CPU motherboard. The benefit is that the components are easier to cool and users can choose which components they want to upgrade and are not forced to upgrade everything at the same time. The companies demonstrated the technology Tuesday in Munich, Germany at the annual Fujitsu Forum.

Intel's disaggregated rack has been building throughout 2013, beginning with the Open Compute Project announcement in January where a collaboration with Facebook defined next-generation rack technologies. After further demonstrating silicon photonics and a live working Rack Scale Architecture solution, Fujitsu has now reinforced a strategy of delivering a complete solution including cables and connectors that are optimized for photonics, with the first Intel Silicon Photonics link carrying PCI Express protocol.

Light vs. Heat

The photonics solution allows components to communicate using fiber optic cabling rather than electrical wiring. The new Fujitsu server relies on a FPGA (field-programmable gate array). Fujitsu took two standard Primergy RX200 servers and added an Intel Silicon Photonics module into each along with an Intel designed FPGA, which handled the necessary signal conditioning to make PCI Express “optical friendly." Using Intel Silicon Photonics they were able to send PCI Express protocol optically through an MXC connector to an expansion box with several solid state disks and Xeon Phi co-processors.

The resulting benefits from this architected solution include the ability to  increase the storage capacity of the server, ability to increase the effective CPU capacity of the Xeon E5's, and cooling density - or how much heat needs to be cooled per cubic centimeter. Photonic signaling has 2 fundamental advantages over copper signaling. One is the noise caused by electromagnetic radiation (EMI) from adjacent wires, and a second is simply lighter cables.

Intel has more than 10 years of experience in working with silicon photonics (SiPh), and is focusing on a full line of solutions around SiPh modules.