On the Wavelength-Selective Nature of Rayleigh Backscattering in Single-Mode Fibers

Spectral measurements of the Rayleigh backscattered light in a single-mode fiber are performed for a white input source. The measured spectrum of the backscattered light from a 45 cm-long fiber exhibits a jagged intensity profile that is highly wavelength-dependent. Spectra from different fiber types were compared with model predictions based on small fluctuations of the fiber refractive index on a centimeter scale, generating interference fluctuations on the spectrum of the backscattered light. The agreement between the statistics of measured data and model simulations confirms the ergodic nature of the phenomenon and supports that optical interference is behind the wavelength-selective nature of Rayleigh backscattering in single mode fibers. Experimental results clearly demonstrate that white light becomes colored when backscattered in a single mode fiber.