To highlight state-of-the-art research activities for ensuring that fiber optic communication systems can handle rapidly increasing demand, editors of the Optical Society’s (OSA) journal Optics Express have published Focus Issue: Space Multiplexed Optical Transmission. The special issue was organized and edited by Guifang Li of the University of Central Florida, Xiang Liu of Bell Labs, Alcatel-Lucent, and Magnus Karlsson of Chalmers University of Technology in Sweden. Optical fiber communication is the backbone for the telecommunication infrastructure that supports the Internet. The publication describes various approaches to increase the information-carrying capacity of optical fibers. One technique, space-division multiplexing (SDM), uses fibers with seven cores rather than a single one. By using all seven, seven independent signals can be carried, and the fiber capacity can thus, in principle, be increased sevenfold. In other approaches, such as mode-division multiplexing (MDM), a single core carries multiple information channels, each associated with a different physical shape of the light field, also increasing the fiber capacity. “We hope this collection will stimulate future research on this subject to address the remaining fundamental and practical challenges, potentially enabling dramatic capacity growth in future optical communication systems,” Li said. The scientific papers on this research are compiled in Optics Express, Vol. 19, Issue 17. For more information, visit: www.opticsinfobase.org/oe