DTW-based nonlinear spatial position correction in OFDR for ultra-large strain sensing up to 20000 με.

Area of Science:

• Optoelectronics
• Fiber optic sensing
• Materials science

Background:

• Optical Frequency Domain Reflectometry (OFDR) is crucial for distributed sensing.
• Conventional cross-correlation methods fail under ultra-large strain conditions (>1%).
• Accurate strain demodulation under extreme deformation remains a challenge.

Purpose of the Study:

• To propose a dynamic time warping (DTW)-based nonlinear spatial position correction method for OFDR.
• To overcome the limitations of conventional methods in ultra-large strain environments.
• To enhance the precision and range of strain measurement in distributed sensing.

Main Methods:

• Developed a DTW-based nonlinear spatial position correction technique.
• Utilized adaptive, point-by-point nonlinear mapping of Rayleigh backscattering (RBS) spectra.
• Simultaneously compensated for intra-window scale distortion and inter-window positional drift.

Main Results:

• Achieved robust strain measurement up to 20000 με (2%) over a 50m fiber.
• Maintained a high spatial resolution of 2mm.
• Demonstrated a twofold expansion of OFDR's measurable strain range.

Conclusions:

• The DTW-based method successfully addresses OFDR limitations under ultra-large strain.
• This advancement significantly improves high-precision strain demodulation capabilities in extreme deformation scenarios.
• The proposed technique expands the applicability of OFDR in demanding sensing applications.