Capacity Limits of Spatially Multiplexed Free- Space Communication

Abstract:  Orbital angular momentum, a physical property of electromagnetic waves, has been proposed as a new degree of freedom for multiplexing information in optical fibres and free-space optical links, generating significant interest in the scientific community. However, the capacity of orbital angular momentum multiplexing has not been established or compared to other multiplexing techniques. Here, we show that orbital angular momentum multiplexing is not an optimal technique for realizing the capacity limits of free-space communication channels, and is outperformed by conventional line-of-sight multi-input multi-output transmission and by conventional spatial-mode multiplexing.

Biography:  Joseph M. Kahn is a Professor of Electrical Engineering at Stanford University. His research addresses communication and imaging through optical fibres, including modulation, detection, signal processing and spatial multiplexing. He received A.B. and Ph.D. degrees in Physics from U.C. Berkeley in 1981 and 1986. From 1987-1990, he was at AT&T Bell Laboratories, Crawford Hill Laboratory, in Holmdel, NJ. He was on the Electrical Engineering faculty at U.C. Berkeley from 1990-2003. In 2000, he co-founded StrataLight Communications, which was acquired by Opnext, Inc. in 2009. He received the National Science Foundation Presidential Young Investigator Award in 1991 and is a Fellow of the IEEE.