Spatial Domain Multiplexing is a technique that increases the capacity of an optical fiber system by transmitting multiple independent data streams or sensing signals simultaneously through spatially distinct channels, such as individual fibers within a multi-fiber cable or separate spatial modes within a multimode or few-mode fiber. In distributed fiber-optic sensing, it enables parallel acquisition across multiple fiber paths, improving coverage, spatial resolution, and bandwidth without requiring additional cable deployment or hardware clocks for synchronization.
We demonstrate distributed fiber-optic acoustic sensing that employs a mechanical synchronizer to achieve sample-level synchronization of signals across independent sensors.This enables phase-noise suppression and bandwidth extension in standard multi-fiber optical cables without hardware modification.