Optical polarization multiplexing-based integrated sensing and communication system on optical fiber

In this paper, we propose a novel, to our knowledge, fiber-based integrated sensing and communication (ISAC) system by utilizing polarization multiplexing. Here, orthogonal polarization states are employed to independently carry the communication and sensing signals, thereby effectively reducing the mutual interference of communication and sensing signals. Additionally, by integrating intensity modulation direct detection (IMDD) with an optical frequency domain reflectometry technique, the system enables integration of high-speed communication and high-resolution fiber sensing over the same wavelength without time-domain resource contention. As for our scheme, only a one-time polarization state calibration at the communication receiver is needed to be employed for achieving the optimal performance, which can retain the identical receiver architecture as the conventional IMDD systems, thereby greatly reducing the implementation complexity and deployment cost of the ISAC on optical fiber (ISAC-OF) system. The simulation experiment results show that, over 20 km of standard single-mode fiber, our method supports a data rate of 25 Gbps while achieving a sensing resolution better than 20 cm with a maximum 3 cm reflection localization error. Additionally, we also give a comprehensive qualitative analysis of the ISAC-OF system with respect to polarization crosstalk, signal power allocation, and overall transmission performance for further verifying our scheme used in the ISAC system.