Terahertz Heterodyne Communication Using GaAs Field-Effect Transistor Receiver

We report the first successful terahertz heterodyne communication using a field-effect transistor for detection. The communication is a real-time transmission of an uncompressed high-definition TV signal at a data rate of 1.5 Gbps with a 307-GHz carrier frequency. The emitter is a frequency-multiplied amplifier chain whose last stage is a second harmonic mixer that multiplies the carrier signal by the data. The receiver only consists of a GaAs high-electron-mobility transistor that acts as a quadratic receiver, and two 20-dB-gain amplifiers, no limiting amplifier or forward error correction were used. A direct communication would be impossible with such a combination of modulation scheme at emission and quadratic detection at reception, while it is possible in a heterodyne configuration. In addition, for the same source power, the heterodyne scheme allows to increase the communication bandwidth from 80 MHz to more than 2 GHz for a local oscillator power of -8 dBm.