Bidirectional Spectroscopic Method for Measuring Attenuation and Intrinsic Emission Spectra in Fluorescent Optical Fibers

In this study, we propose a method for evaluating both the attenuation coefficient spectrum and the intrinsic emission spectrum of fluorescent fibers. The method is based on scanning the excitation position along the fiber and measuring fluorescence spectra simultaneously at both ends. The attenuation coefficient is extracted from the square root of the spectral ratio, and the intrinsic emission spectrum is obtained by normalizing spectra at a reference wavelength. Measurements with a plastic scintillation fiber (Kuraray SCSF-78) yielded attenuation spectra consistent with specifications, confirming the validity of the method. The approach is also applicable to luminescent solar concentrators and fluorescent-fiber antennas for visible light communication.