Improved efficiency of Pr-doped sulfide fiber amplifier using a dual pump scheme

Summary form only given.Low phonon energy sulfide glasses show promise as a potential host for an efficient Pr doped fiber amplifier, operating in the second telecommunications window at 1.3 /spl mu/m. The high efficiency arises from a combination of higher radiative rates and reduced nonradiative relaxation rates in these glasses, which reduces the nonradiative quenching of the upper laser level (/sup 1/G/sub 4/). However, it has recently been shown that the low nonradiative relaxation rates in these glasses also have the detrimental effect of increasing the lifetime of the lower laser level (/sup 3/H/sub 5/), which leads to bottle-necking of the population in the /sup 3/H/sub 5/, and a reduction of gain at shorter wavelengths. In this work we show that this bottle-necking can be partially alleviated by adding a second pump on the short wavelength side of the /sup 3/H/sub 5/-/sup 1/G/sub 4/ transition.