@inproceedings{JohstPerlotHanneetal., author = {Johst, Abraham and Perlot, Nicolas and Hanne, Peter and Rothe, Marcel and Schreier, Andy and N{\"o}lle, Markus and Freund, Ronald}, title = {Bidirectional real-time 10-Gbit/s free-space optical link with a 4-aperture array under strong scintillation}, series = {2023 IEEE International Conference on Space Optical Systems and Applications (ICSOS)}, booktitle = {2023 IEEE International Conference on Space Optical Systems and Applications (ICSOS)}, doi = {10.1109/ICSOS59710.2023.10491221}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-20383}, pages = {6}, abstract = {We report on a demonstration of a bidirectional, multi-aperture free-space optics (FSO) system and discuss general system design aspects. A multi-aperture terminal is used for spatial diversity. On both sides, a real-time signal combining takes place on field-programmable gate arrays. The combined signals are weighted by their corresponding channel powers. Small form-factor C-band pluggable modules provide the optoelectrical interfaces of the 10-Gbit/s on/off-keying signals. A custom-built multi-channel bit error tester is used on both terminals for performance determination. Each aperture has an optical tracking system, is coupled to a bidirectional single-mode fiber and emits an optical power of 4 dBm.}, language = {en} } @inproceedings{JohstMollePerlotetal., author = {Johst, Abraham and Molle, Lutz and Perlot, Nicolas and Rothe, Marcel and Rohde, Michael and N{\"o}lle, Markus}, title = {Data-Aided Multi-Format DSP for Robust Free-Space Coherent Optical Communication}, series = {2024 IEEE International Conference on Wireless for Space and Extreme Environments (WiSEE)}, booktitle = {2024 IEEE International Conference on Wireless for Space and Extreme Environments (WiSEE)}, doi = {10.1109/WiSEE61249.2024.10850117}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:523-20390}, pages = {7}, abstract = {The increasing demand for fast and license-free satellite feeder links has put optical free-space communications on the research agenda. To compensate for atmospheric turbulence utilizing spatial diversity and post-DSP combining, a DSP is needed that works reliably even at very low SNRs. For this purpose, a custom multi-format data-aided equalizer is developed and its performance is analyzed under various conditions in a dual-polarization coherent transmission system. Numerical simulations and a field test over a 3.2-km free-space optical link are used to validate the DSP design, and show stable DSP performance for a 32 GBd coherent transmission at SNR-values down to 0 dB, even for DP-16QAM modulation.}, language = {en} }