Full-photonics up- and downconversions for W-band 16-QAM signal wireless delivery over 30.4 km with advanced equalizations

We have experimentally demonstrated a communication system with an ultra-long sea surface wireless distance of 30.4 km and high-speed 16-quadrature amplitude modulation (16-QAM) data transmission at the W-band based on full-photonics up- and downconversion technology. Utilizing a frequency- and phase-locked optical two-tone generator, the transceiver ensures a stable millimeter-wave (mmW) signal at 76.4 GHz for transmission. Furthermore, we proposed a Volterra nonlinear equalization (VNLE) algorithm to compensate for nonlinear damage in signal transmission. Thanks to full-photonics conversion technology and advanced post-equalization digital signal processing algorithms, we have achieved a data transmission rate of 16 Gb/s 16-quadrature amplitude modulation (16-QAM) signal over a sea surface distance of 30.4 km. It is worth noting that as a special type of channel, water vapor density and atmospheric conditions will greatly affect the signal transmission. To the best of our knowledge, this is the first demonstration of a full-photonics 16-QAM signal exceeding 30 km at the W-band on a single channel, achieving a rate-distance product of 16 Gb/s × 30.4 km = 486.4 Gbps·km.