Rare Earth-Doped Fluoride Fiber Amplifiers and Fiber Lasers

Abstract

This paper describes the latest results on fluoride fiber amplifiers and fiber lasers doped with erbium (Er3 +), neodymium (Nd3 +), praseodymium (Pr3 +), and thulium (Tm3 +) ions. In an Er3 +-doped fluoride fiber, the 1.5 μm gain bandwidth of 35 nm is wider than that of an Er-doped silica fiber. Er3 +-doped fluoride fibers also have many kinds of emission lines such as 0.55, 0.85,0.98, and 2.1 μm which have not been seen in an Er-doped silica fiber. Nd3 +-doped and Pr3 +-doped fluoride fibers have the potential for use as a 1.3-μm optical amplifier. It is not possible, however, to use silica fiber as the host glass fiber in either case. These two active ions are compared. Finally, 1.47- and 1.9-μm Tm3 +-doped fluoride fiber amplifiers are described. From a practical point of view, these four rare earth-doped fluoride fibers are especially important because they have transition wavelengths near the 1.3- and 1.55-μm communication windows.