Temperature-dependent characteristics of bismuth-doped fiber amplifier operating in a 1720-nm band

The temperature dependencies of the characteristics of a bismuth-doped fiber amplifier (BDFA) for a 1725-nm band have been studied. The amplifier was backward-pumped with an Er-Yb-codoped fiber laser at 1568 nm. A peak gain of 24 dB, a 3-dB gain bandwidth of 55 nm, a noise figure of 5 dB and slope gain efficiency of 0.17 dB/mW at room temperature have been obtained. It has been shown that peak gain of the BDFA varies by 25 % in the temperature range from −60 to +60 °C while the noise figure remains almost unchanged. Some possible mechanisms responsible for the thermal behavior of the characteristics of the BDFA are considered.