1550-nm fluorescence efficiency and heat generation of erbium-doped fiber pumped by pulsed and quasi-continuous-wave lasers

Radiation hardening commercial off-the-shelf erbium doped fibers by optimal photo-annealing source

“…Among them, the unique photo-annealing (PA) method provides excellent annealing effect of diminishing EDF's RIA for commercial off-the-shelf (COTS) EDFs [4][5]. Recently, photo-annealing of using 980-nm continuous light on Ge-doped [6] and Al-doped [6,10] EDFs, 532-nm continuous light on both Ge-and Al-doped EDFs [6,10], and 800-nm pulsed light on Al-doped EDF [11][12][13] has been performed. The 980-nm photo-annealing light showed only partial RIA recovery, but the 532-nm photo-annealing light showed nearly total RIA recovery in the spectral range between 900 nm and 1750 nm [10].…”

“…To decrease the RIA, several radiation-hardening methods have been proposed, e.g. hydrogen pre-loading [4,5], thermal annealing [6,7], and photo-annealing [8,9,[10][11][12][13][14][15][16][17]. For thermal annealing, it needs to take up to 300°C to decrease RIA.…”