Channel measurements are an important prerequisite for the investigation of free-space optical communication through the atmosphere and the design as well as optimisation of systems. In addition, newly developed concepts, such as methods for single-mode fibre coupling or diversity methods for suppressing signal interference, must be implemented and demonstrated.
The Oberpfaffenhofen Optical Ground Station is regularly used for this purpose. It is located on the roof of the institute building and has a telescope to which various electro-optical systems can be directly attached. So far, measurements of the turbulent optical transmission channel, tests of various measuring instruments (e.g. wavefront sensors for adaptive optics) as well as the investigation and demonstration of quantum key distribution have been carried out with it.
Currently, a telescope system with an aperture diameter of 80cm is used, which has satellite and aircraft tracking functionality. The processing of the received signal is made possible by means of a so-called Coudé feed-through in the station's control room (Coudé room below the ground station). The signal arriving there is corrected and processed using adaptive optics. It is also possible to use the reverse path to transmit beacon laser signals to mobile platforms and geostationary satellites through the optics and telescope. This enables various applications from classical laser communication to the transmission of quantum communication signals including quantum key distribution. The diversity of experimental applications - especially with regard to the use of adaptive optics and beacon laser systems - enables us to achieve our research goals.
>> On 12.10.2022 the OGSOP was officially inaugurated.
Image: DLR (CC BY-3.0)