1.2-Gbit/s Data-Rate Free-Space Optical Communications with Terahertz Laser

Terahertz quantum cascade lasers offer promising capabilities for free-space optical communication, bridging the gap between microwave electronics and optical fiber technologies. We report the first experimental demonstration of free-space optical communication at terahertz frequencies, utilizing a quantum cascade laser transmitter and a room temperature Schottky barrier diode receiver at 1.2 Gbit/s data rate. We achieve reliable data transmission over a 0.5m free-space distance, with bit error rates dropping below the hard-decision forward error correction threshold (3.8×10−3) as the received optical power increases. This gigabit-scale communication link highlights the potential of THz photonic devices for high-speed, short-range wireless communications in 6G and beyond.