Multi-resolution φ-OTDR based on chirped pulse compression using multi-order sideband excitation

This paper proposes a multi-resolution φ-OTDR scheme that combines multi-order sideband excitation with matched filtering. By precisely controlling the modulation function, first-, second-, and third-order sidebands are simultaneously generated. Matched filtering is applied to extract each sideband individually, enabling multiple spatial resolutions within a single measurement. Numerical simulations demonstrate that the method achieves spatial resolutions of 12.0 m, 6.0 m, and 4.0 m simultaneously. The technique features tunable resolution, a simple system structure, and flexible signal processing, offering a concise and effective framework for multi-resolution distributed sensing.