Aluminum-related temperature dependence in erbium-doped fibers: optical loss, laser output power and the mechanism

The irradiation damage effects of erbium-doped fibers for space laser communications have been extensively studied, however, there are few reports on how the performance of erbium-doped fibers changes under the conditions of temperature changing and irradiation in the space environment. In this work, the temperature dependence of loss and gain performance in erbium-doped fibers before and after irradiation was investigated. Temperature induced loss variation after irradiation is -19.7 and 21.08 dB/km at 1200 nm in -25 ℃ and 70 ℃, respectively. Notably, the loss in the non-irradiated fiber is almost unchanged in this temperature range. In the gain performance test, the 1550 nm laser output power of the irradiated fiber decreased 43% when temperature rose from -25 ℃ to 70 ℃. In contrast, the variation of pristine fiber is only 10%. This work helps to understand the properties of erbium-doped optical fiber change under irradiation and temperature-varying environments. It is also proposed that the absorption intensity of Al-OHC defects varies with temperature leading to the fiber's temperature dependence.