For applications that do not require a polarized signal, Nufern has introduced the SM-ESF-7/125 erbium-doped nonpolarization-maintaining fiber. Operating over the C- and L-bands, the fiber has a mode-field diameter of 8.8 ±1.0 μm at 1550 nm, and 9.1 ±1.0 μm at 1620 nm. Its peak absorption near 1530 nm is 55 ±5 dB/m, and its second-mode cutoff is 1400 ±60 nm. The numerical aperture is 0.15. Coated with a UV-cured dual-acrylate material, the fiber operates over temperatures from –40 to 85 °C. Core-clad concentricity is <0.5 μm, and coating-clad offset is <5 μm.