Forward Brillouin scattering acoustic impedance sensor using thin polyimide-coated fiber

Area of Science:

• Optomechanics
• Fiber optics sensing
• Acoustic impedance measurement

Background:

• Optomechanical sensors utilize fiber optics for liquid analysis.
• Forward-stimulated Brillouin scattering (FSBS) probes material properties via light-sound interaction within fibers.
• Precise measurements require a low-loss interface, often necessitating impractical fiber coating removal.

Purpose of the Study:

• To develop a practical optomechanical sensor for measuring acoustic impedance of surrounding liquids.
• To demonstrate accurate acoustic impedance measurements using a standard optical fiber with intact coating.

Main Methods:

• Utilized forward-stimulated Brillouin scattering (FSBS) for optomechanical sensing.
• Employed a commercially available 80-μm-diameter optical fiber with an 8-μm-thick polyimide coating.
• Measured acoustic impedances of surrounding liquids without removing the fiber coating.

Main Results:

• Achieved accurate measurement of acoustic impedances for surrounding liquids.
• Demonstrated the feasibility of using coated optical fibers for sensing applications.
• Maintained the mechanical strength of the optical fiber throughout the measurement process.

Conclusions:

• The developed method enables accurate acoustic impedance measurements using standard optical fibers with intact coatings.
• This approach offers a practical alternative to existing methods that require fiber coating removal.
• The intact coating preserves fiber mechanical strength, enhancing sensor robustness.