Impurity Absorption Losses in the Infrared Region due to 3d Transition Elements in Fluoride Glass

Optical absorption spectra of 3d transition elements (Ti, V, Cr, Mn, Fe, Co, Ni and Cu) in zirconium tetrafluoride based glasses are measured. Absorption bands of Fe, Co, Ni and Cu, having their peaks in the near infrared region, extend their tails beyond a wavelength of 2 µm. Absorption losses due to these elements are less than several dB/km/ppm at a wavelength of 3 µm. The losses are less than one-tenth of those cansed by rare earth elements. Thus contamination with 3d transition elements exerts a less adverse influence upon the transmission loss in fluoride glass optical fibers than that due to rare earth elements.