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arXiv · 2601.06569

Spontaneous Brillouin Scattering in a Few-Mode Optical Fiber

Hikari Kikuchi·Rekishu Yamazaki
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Abstract

We report a comprehensive experimental study of spontaneous Brillouin scattering in a few-mode optical fiber, resolving both forward and backward scattering processes for intra- and inter-modal interactions. Using heterodyne detection, Stokes and anti-Stokes components without external acoustic excitation are observed and quantitatively extracted Brillouin shifts, linewidths, and gain coefficients. Forward scattering is mediated by guided torsional-radial acoustic modes with frequencies ranging from MHz to GHz, while backward scattering involves longitudinal core-guided modes at frequencies of tens of GHz. These results provide calibrated benchmarks for Brillouin interactions in few-mode fibers, offering insights relevant to phonon-based quantum applications and mode-selective optomechanics.

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Hikari Kikuchi, Rekishu Yamazaki. 2026-01-10. Spontaneous Brillouin Scattering in a Few-Mode Optical Fiber. https://arxiv.org/abs/2601.06569

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