Fig. 5: THz FSO communication system performance through BER analysis.
From: Free-space optical communications at 4 Gbit/s data rate with a terahertz laser
BER as a function of received optical power for NRZ-OOK signals transmitted at 1 Gbit/s (black circles), 2 Gbit/s (red squares), 3 Gbit/s (blue diamonds), and 4 Gbit/s (green triangles) using a THz QCL over a 0.5 m free-space link. The BER decreases with increasing received optical power for all data rates, demonstrating improved signal quality. The system achieves BERs below the HD-FEC threshold (black dashed line) of 3.8 × 10−3 at received powers of approximately 30 μW for 1 Gbit/s, 34 μW for 2 Gbit/s and 3 Gbit/s, and 40 μW for 4 Gbit/s. These results highlight the trade-off between data rate and the required optical power to reach the HD-FEC threshold.
