Photo-elastic Constant of Silica Fibers at Visible Wavelengths

In this paper, we measured the photo-elastic constant of silica-fibers as a basic constant of silica fibers for a wavelength range of λ =0.4 μm ∼ 0.65 μm (visible wavelengths). Previously, we measured stress-induced time of flight variations for λ =0.7 μm ∼ 1.7 μm and we evaluated the photo-elastic constant for these wavelengths. Recently, photonic crystal fibers (PCFs) have been devel- oped and they have an endlessly single mode property. With these fibers, wide wavelength ranges may be used in future. For this purpose, it is very important to evaluate the photo-elastic constant at visible wavelengths. For measurements, the phase method was used to detect phase changes of intensity-modulated wave propagating in a graded-index fiber with and without stress. Combined with the previously measured data for λ =0.7 μm ∼ 1.7 μm, we evaluate the photo-elastic constant of silica- fibers for wavelength ranges of λ =0.4 μm ∼ 1.7 μm.