Compact broadband amplified spontaneous emission in Tm³⁺-doped tungsten tellurite glass double-cladding single-mode fiber

We reported the ~2 μm amplified spontaneous emission (ASE) performance of highly Tm3+-doped (3.76 × 1020ions/cm3) tungsten tellurite single-mode fibers. The double-cladding fiber was pumped by a commercial 792 nm laser diode without any reflectors. Broadband ASE spectra with the bandwidth (FWHM) varying from ~45 nm to ~140 nm were achieved in a fiber length of 34 cm. The maximum output power was ~34 mW, with a slope efficiency of 4.8%. The ASE beam quality factor (M2) was 1.8. The dependence of output power, ASE mean wavelength, and bandwidth on the launched pump power and fiber length were discussed in detail.