Photonics-assisted mmW integrated sensing and communication system with polarization-insensitive capability

The birefringence in optical transmission leads to the polarization mismatch between modulation light and optical local oscillation, severely degrading the performance of photonics-assisted millimeter-wave (mmW) integrated sensing and communication (ISAC) systems. In this paper, we propose a photonics-assisted mmW ISAC system with polarization-insensitive capability. The proposed system eliminates the polarization sensitivity by jointly using a dual-polarization linear frequency-modulated (DP-LFM) waveform with an X-shaped time-frequency distribution and the Alamouti polarization-time block coding (PTBC). The experimental results confirm that the proposed mmW ISAC system simultaneously achieves a range resolution of 1.5 cm and a transmission capacity of 48 Gbps. In addition, both the mmW sensing and communication exhibit good robustness to the random polarization changes.