Recent Progress in Distributed Brillouin Sensors Based on Few-Mode Optical Fibers

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Brillouin scattering involves photon-phonon interactions in optical fibers.
• Distributed Brillouin sensors utilize spectral shifts related to temperature and strain.
• Few-mode optical fibers (FMFs) guide multiple spatial modes, enabling new light-matter interactions.

Purpose of the Study:

• To review recent advancements in distributed Brillouin sensors using FMFs.
• To highlight the unique properties of intermodal stimulated Brillouin scattering (SBS) and Brillouin dynamic grating (BDG) in FMFs.
• To explore the application of these phenomena for measuring fiber properties and environmental variables.

Main Methods:

• Investigating intermodal SBS coupling between different spatial modes in FMFs.
• Analyzing Brillouin dynamic grating (BDG) phenomena involving four-photon interactions.
• Characterizing the unique spectral responses arising from FMF spatial mode structures.

Main Results:

• Intermodal SBS and BDG in FMFs exhibit distinct spectral characteristics.
• These intermodal processes allow for direct measurement of polarization and modal birefringence.
• The spectral shifts are sensitive to environmental factors like strain and temperature, enabling distributed sensing.

Conclusions:

• FMF-based distributed Brillouin sensors offer enhanced capabilities beyond traditional single-mode fiber sensors.
• Intermodal scattering processes in FMFs provide novel pathways for high-sensitivity measurements.
• This review underscores the potential of FMFs for advanced sensing applications.