SNR enhancement in high-resolution phase-sensitive OTDR systems using chirped pulse amplification concepts

Area of Science:

• Optics
• Sensor Technology
• Signal Processing

Background:

• Phase-sensitive optical time-domain reflectometry (φOTDR) offers distributed sensing for mechanical/environmental variations.
• Current φOTDR spatial resolution is limited by probe pulse width, balancing signal-to-noise ratio (SNR) and nonlinear effects.
• Achieving higher resolution requires overcoming trade-offs between pulse energy, SNR, and peak power limitations.

Purpose of the Study:

• To present a novel technique for enhancing SNR in φOTDR sensors.
• To achieve centimeter-level spatial resolution in distributed sensing.
• To overcome the limitations of traditional pulse width constraints in φOTDR.

Main Methods:

• Inspired by chirped pulse amplification concepts.
• Implementation of a novel technique to increase SNR in φOTDR systems.
• Utilizing short probe pulses for high spatial resolution.

Main Results:

• Achieved an SNR increase of 20 dB compared to traditional architectures.
• Demonstrated centimeter-level spatial resolution.
• Successfully detected strain events with a spatial resolution of 1.8 cm.

Conclusions:

• The novel technique significantly enhances SNR in φOTDR.
• Centimeter-level spatial resolution is attainable, surpassing previous limitations.
• This advancement enables more precise distributed sensing for mechanical and environmental monitoring.