Demonstration of 120 Gbit/s 64-QAM Wireless Link Operating in the 300 GHz Band

This paper demonstrates a 120 Gbit/s 64-Quadrature Amplitude Modulation (64-QAM) transmission link using all-electronics sub-harmonic mixers for the transmitter and the receiver operating in the 300 GHz band. The wireless signal is propagated through a non-line-of-sight free space link where reflections from 2 mirrors provide a channel length of 3 m over-the-air transmission between the transmitter and the receiver modules. Here, we demonstrate that an accurate correction of different error sources such as channel impairments of the 300 GHz wireless link as well as the combined effects of hardware amplitude and phase impairments can successfully be achieved for the high spectral-efficiency 64-QAM modulation scheme. The measured bit error ratio of the calibrated testbed is under the soft-decision forward error correction (SD-FEC) threshold of
$2.7\times 10^{-2}$
up to 120 Gbit/s with 20% overhead giving a net data rate of 100 Gbit/s post-FEC. To the best of our knowledge, this is the highest 64-QAM performance achieved using an electronics-based transmitter in the 300 GHz band.