Simultaneous distributed sensing and communication enabled by space and wavelength division multiplexing in a field-deployed seven-core fiber

Integrated sensing and communication (ISAC) systems enable communication while concurrently endowing optical fiber with sensing capability, utilizing telecommunication networks to detect signals such as traffic. Multi-core fiber provides abundant exploitable spatial channels for ISAC systems. This work proposes a space division multiplexing distributed acoustic sensing (SDM-DAS) scheme for ISAC. By leveraging multi-component sensing signals transmitted through multiple fiber cores, SDM-DAS achieves a sensing sensitivity of 1.78p ε /Hz at 10 km under a spatial resolution of 20 m. It also demonstrates a 10 dB suppression in fading noise and a detection bandwidth three times greater than that of conventional DAS. The system employs space and wavelength division multiplexing to enable co-propagation of communication and sensing signals within individual cores of a 16.5 km field-deployed seven-core fiber, achieving real-time traffic transmission with a net capacity of 117 Tb/s. Experimental results show that the setup introduces no inter-core crosstalk and does not degrade the bit error rate of the concurrently operating communication system. Furthermore, the proposed ISAC system integrating SDM-DAS successfully detects vibration signals from vehicular traffic and metro operations in real-world field deployment.