Holistic co-design of fibre-optic distributed acoustic sensing and coherent communication

Integrating sensing into communication is crucial for the fully-connected and intelligent development of modern life. However, existing fiber-optic sensing and communication systems merely coexist without inadequate resource sharing, resulting in limited scalability for large-scale deployment. Here, we propose a holistically co-designed sensing and communication (CSAC) framework that incorporates multi-level optimization: (i) a dual-function pilot signal that shares time and spectrum resources; (ii) a simplified system using a single transmitter to simultaneously generate multi-tone pilot and subcarrier communication signals; (iii) a point-to-multipoint (P2MP) network that distributes pilot signals for multi-user frequency synchronization and enhanced acoustic sensing response. Our approach achieves multi-point frequency synchronization with an accuracy of 1.56 MHz and enhances acoustic sensing response to 12 kHz. By introducing the on-chip modulators to generate multi-frequency optical comb, the response bandwidth is further expanded to 28 kHz. This CSAC framework efficiently supports dense communication and diverse sensing, offering an eco-sustainable solution for the future optical networks.