Tone-reservation-enabled low-CSPR KK reception in a 126-GHz D-band photonic fiber-wireless link

We experimentally demonstrate tone-reservation (TR)-enabled low-CSPR Kramers-Kronig (KK) reception in a 126-GHz D-band photonic fiber-wireless link. Rather than treating TR only as a conventional peak-to-average-power-ratio (PAPR) reduction method, we use it as a waveform-shaping approach to relax the CSPR requirement for stable KK field reconstruction, thereby enabling KK reception at a lower favorable CSPR. The experiment is performed over 10-km single-mode fiber and 2-m wireless transmission. Across 4-, 6-, and 8-GHz signal bandwidths, the TR-assisted waveform shifts the favorable CSPR operating point toward a lower-CSPR region compared with conventional virtual-carrier OFDM. Net data rates of 13.46, 20.17, and 26.91 Gbps are achieved, respectively. These results indicate that transmitter-side peak suppression can serve as a practical route to low-CSPR KK reception through CSPR operating-point optimization in photonic D-band fiber-wireless links.