Proportions of the element erbium, the element aluminum, and the element phosphorus are adjusted during optical fiber preparation so that aluminum phosphate is formed around the element erbium in a prepared optical fiber, a probability that the element erbium in the optical fiber transits to a high energy level is reduced, and an excited-state absorption effect of the element erbium in the optical fiber on an optical signal is suppressed.

An optical glass having the following oxides in mass percentage relative to a total mass of the optical glass: 10.0%-30.0% SiO.sub.2, 10.0%-30.0% P.sub.2O.sub.5, 0.1%-5.0% B.sub.2O.sub.3, 0.1%-10.0% Al.sub.2O.sub.3, 0.1%-10.0% Rn oxides, 1.0%-20.0% R oxides, 0.1%-5.0% ZrO.sub.2, 10.0%-30.0% TiO.sub.2, 15.0%-50.0% Nb.sub.2O.sub.5, 0.1%-10.0% Ln oxides, and 0.1%-10.0% WO.sub.3, wherein TiO.sub.2+Nb.sub.2O.sub.5+P.sub.2O.sub.5+the R oxides accounts for 60.01% or above.