Fujitsu Develops Optical Transmission Technology to Double Communications Distance between Servers
Fujitsu today announced the development of technology that doubles the maximum distance of optical communications between servers to 200 meters while using conventional fiber-optic cabling. In a distributed-computing system, adding servers is a way to increase the system’s overall processing capacity. However, as the floor space of datacenters gets bigger to accommodate more servers, a point of concern has been lengthening the optical communications paths that connect the servers. The fiber-optic cables that are commonly used for inter-server optical communications suffer from a phenomenon called modal dispersion, by which the high-speed characteristics of the optical waveform deteriorate, and this limits the maximum distance the optical signal can reach. Fujitsu has developed a new optical transmitter structure to reduce modal dispersion.
Based on the modal dispersion analysis, Fujitsu devised an optical transmitter with an intermediary optical waveguide having a core width of 25 μm. As a result of fabricating the prototype optical transmitter, Fujitsu was able to confirm that, even when used with conventional multimode fiber, at transmission rates of 25 Gbps, it doubled the maximum transmission distance to 200 meters. From a floor space estimation, this has the potential to connect four times as many servers at the maximum, increasing distributed-computing performance in large-scale datacenters. The technology developed by Fujitsu was confirmed to double the maximum distance that optical communications can cover, which would enable the number of servers that could be connected together to increase by up to four times. This increases distributed processing capacity among servers in a large-scale datacenter.