High resolution DAS via sinusoidal frequency scan OFDR (SFS-OFDR)

Area of Science:

• Optoelectronics
• Fiber optic sensing
• Signal processing

Background:

• Direct frequency modulation in Optical Frequency Domain Reflectometry (OFDR) based Distributed Acoustic Sensing (DAS) presents significant advantages.
• However, achieving linear frequency scans is a major challenge, limiting OFDR-based DAS performance.
• Existing methods struggle with scan parameter limitations due to linearity requirements.

Purpose of the Study:

• To introduce a novel method for analyzing sinusoidal frequency modulated light for OFDR-based DAS.
• To demonstrate the effectiveness of this method for both static and dynamic sensing applications.
• To overcome the limitations imposed by linearity requirements in direct frequency modulation for OFDR-based DAS.

Main Methods:

• Development of a Sinusoidal Frequency-modulated OFDR (SFS-OFDR) technique.
• Analysis of sinusoidal frequency modulated light signals.
• Projection of measured signals onto sinusoidal phase terms for spatial information retrieval.

Main Results:

• Successful demonstration of SFS-OFDR for static and dynamic sensing.
• Overcoming the linearity requirement associated with direct frequency modulation.
• Enabling the utilization of advantages offered by direct frequency modulation without its inherent limitations.

Conclusions:

• SFS-OFDR provides a viable solution for enhancing OFDR-based DAS performance.
• The method allows for improved spatial information retrieval in dynamic and static sensing.
• This approach removes the critical linearity constraint, broadening the applicability of direct frequency modulation in DAS.