Wireless communication demonstration at 4.1 THz using quantum cascade laser and quantum well photodetector

A wireless terahertz (THz) analogue communication link using a quantum cascade laser (QCL) as the source and a quantum well photodetector as the receiver is demonstrated. The QCL operates in continuous-wave mode. By directly modulating the QCL emitting at 4.1 THz, analogue signals are transmitted over a distance of 2 m. The circuit-limited modulation bandwidth is about 580 kHz.