Range-scalable distributed acoustic sensing with EDFA repeaters demonstrated over 2227 km

Area of Science:

• Fiber optic sensing
• Acoustic monitoring
• Telecommunications technology

Background:

• Long-haul fiber optic networks are crucial for telecommunications.
• Distributed Acoustic Sensing (DAS) offers valuable monitoring capabilities.
• Integrating DAS with existing infrastructure presents technical challenges.

Purpose of the Study:

• To demonstrate a range-scalable repeatered distributed acoustic sensing (DAS) solution.
• To leverage existing long-haul subsea telecom networks for DAS.
• To achieve low noise and high spatial/temporal resolution in DAS.

Main Methods:

• Utilizing a single-ended DAS interrogation system.
• Deploying the system over a 2227 km fiber line with 39 repeatered spans.
• Implementing wavelength division multiplexing (WDM) for multiple DAS channels.
• Employing add/drop (A/D) multiplexers for span addressing.

Main Results:

• Achieved 10 m spatial resolution.
• Operated at a 1.78 kHz sampling rate.
• Obtained a strain resolution of 35 pε/√Hz for the outermost span.
• Demonstrated < -60 dB crosstalk between spans using A/D multiplexers.

Conclusions:

• The developed DAS solution is range-scalable and compatible with existing subsea telecom infrastructure.
• The system achieves high performance metrics, including low noise and high resolution.
• Wavelength multiplexing and A/D multiplexers enable efficient and selective span monitoring.