THz Communication System at 1.8 THz by Photonics-Based Transmitter and Electronics-based Receiver

We have demonstrated wireless transmission of quadrature phase shift keying (QPSK) signals at 1.8 THz and investigated usability of the frequency multiplier as a local oscillator (LO) source in the heterodyne receiver system for the wireless communication. For the transmitter, THz signals were converted from optical carriers extracted from a broadband optical comb. The receiver system was composed of a hot electron bolometer mixer and a frequency multiplier for the LO. In the transmission experiment, QPSK signals were successfully demodulated. The EVM of the demodulated signal was about 17%, which was lower than that in the case of a phase-locked QCL for the LO reported previously.