Single-mode optical antenna for high-speed and quantum communications

We present optical antenna prototypes that can maintain a link between two standard single-mode fibers with high coupling efficiency. Using standard telecom transmission techniques at 1550 nm, high capacities of 40 Gbit/s or more are achieved. After describing the basic design, we address the necessary design modifications for long distances (e.g. with satellites) or for quantum communication. The extension of the antenna to a telescope array is expected to solve performance limitations caused by eye-safety and atmospheric turbulence.