Improve accuracy and measurement range of sensing in km-level OFDR using spectral splicing method

Area of Science:

• Optoelectronics
• Fiber Optic Sensing
• Metrology

Background:

• Distributed strain sensing is crucial for structural health monitoring.
• Optical Frequency Domain Reflectometry (OFDR) offers high resolution but faces limitations in measurement range and phase noise accumulation over long distances.

Purpose of the Study:

• To propose and demonstrate a novel spectral splicing method (SSM) for OFDR to overcome limitations in measurement length, sensitivity, and range.
• To enable accurate distributed strain sensing over kilometer-long fiber optic cables.

Main Methods:

• Developed a spectral splicing method (SSM) that replaces centralized data processing with segmented processing and spatial position correction.
• Implemented segmented processing to suppress phase noise and expand the processable sweep range.
• Utilized spatial position correction to rectify positional errors, enabling precise spectrum splicing.

Main Results:

• Achieved a strain sensitivity of ±3.2 µɛ (3σ) over a 1 km measurement length with 1 cm spatial resolution.
• Extended the strain measurement range to 10,000 µɛ.
• Reduced spatial position errors from the 10 m to the mm level.

Conclusions:

• The spectral splicing method (SSM) effectively enhances OFDR performance for long-distance distributed strain sensing.
• This technique provides a new solution for high-accuracy, wide-range OFDR sensing at the kilometer level.
• The method addresses phase noise and positional errors, crucial for extending measurement capabilities.