Distributed acoustic mapping based on interferometry of phase optical time-domain reflectometry

• We demonstrate an φ-OTDR-interferometer system for distributed acoustic sensing.
• Phase, amplitude and location of the event can be directly obtained simultaneously.
• Same acoustic source with different intensities is well demodulated in experiment.
• Different acoustic sources with different intensities are also well demodulated.
• Demodulated amplitudes in different intensities show good linear property.

We demonstrate the design and characterization of a distributed optical fiber sensing system based on Michelson interferometer of the phase sensitive optical time domain reflectometer (φ-OTDR) for acoustic measurement. Phase, amplitude, frequency response and location information can be directly obtained at the same time by using the passive 3×3 coupler demodulation. In order to simulate sound profiles of seismic or hydroacoustic imaging, experiments on detection of multiple piezoelectric transducers (PZT) are carried out. The result shows that our system can well demodulate different acoustic sources with different intensities.