Phasorial differential pulse-width pair technique for long-range Brillouin optical time-domain analysis sensors

Area of Science:

• Optoelectronics and Photonics
• Sensing Technologies
• Optical Fiber Communications

Background:

• Brillouin optical time-domain analysis (BOTDA) is a crucial technology for distributed sensing in optical fibers.
• Traditional BOTDA methods face limitations in spatial resolution and susceptibility to non-local effects, especially in long-range applications.
• Enhancing signal-to-noise ratio and measurement contrast remains a key challenge for extending BOTDA capabilities.

Purpose of the Study:

• To introduce and validate a novel phasorial differential pulse-width pair (PDPP) method for BOTDA.
• To demonstrate the PDPP technique's ability to improve spatial resolution and non-local effect tolerance.
• To showcase the potential of PDPP for enhanced signal-to-noise ratio and measurement contrast in long-range BOTDA systems.

Main Methods:

• Theoretical description and numerical simulation of wave propagation using the PDPP method.
• Implementation of a sensor configuration employing a phase-modulated probe wave and RF demodulation.
• Subtraction of complex time-domain traces to extract Brillouin frequency shift information.

Main Results:

• Successful measurement of Brillouin frequency shift distribution over a 50-km fiber.
• Demonstrated robustness of the PDPP technique against significant pump power variations.
• Achieved 1-m spatial resolution with relatively long pulse durations, indicating increased measurement contrast.

Conclusions:

• The PDPP method offers a significant advancement for BOTDA, enhancing spatial resolution and non-local effect tolerance.
• The technique shows strong potential for improving signal-to-noise ratio in long-range BOTDA applications.
• PDPP enables higher measurement contrast, paving the way for more effective distributed fiber sensing.