<title>Recent progress in short-range ultraviolet communication</title>

This paper describes recent advances in the technology for, and implementation of, short-range optical communication links. The approach relies on molecular scattering of ultraviolet wavelengths by the atmosphere to achieve non-line-of-sight, omni-directional communication links. The same technology is also shown to be attractive for certain classes of line-of-sight links. A UV communication testbed implementation is described that is unique, employing research-grade semiconductor sources emitting in the solar-blind region of the UV spectrum, around 275nm. This paper extends previously reported field measurements to longer ranges and to a wider variety of application scenarios, including operation under tree canopy and operation in short-range quasi-line-of-sight links. Field measurements of atmospheric extinction at 275nm are reported and incorporated in a single-scatter propagation model to predict performance of line-of-sight links. Application of UV communication to foliage penetration uplinks is described, and performance is quantified through field measurements.