Intense emission at ∼3.3 µm from Er-doped fluoroindate glass fiber.

Fluoroindate glass fibers with an doping concentration of ∼0.5 were fabricated by using a rod-in-tube method. Pumped by a 976 nm laser diode, intense emission at ∼3.3µ was obtained from a 40 cm long -doped fiber, which could be attributed to the transition → of ions. The calculated emission cross section at ∼3.3µ was ∼3×10, which was ∼1.5 times larger than that of transitions :→ and :→. In addition, broad emissions ranging from 3.1 µm to 3.85 µm were obtained in the -doped fiber under a 976 nm/1973 nm dual-wavelength pumping scheme. Our results indicated that -doped fluoroindate glass fibers had the potential for constructing efficient ∼3.3µ fiber lasers.