Nufern has expanded its NuPower line of active fibers. The PS-ESF-3/125, a photosensitive active fiber, is designed for distributed feedback and distributed Bragg reflector lasers in the C- and L-bands. The fiber’s high erbium concentration enables short-length devices, while its photosensitivity allows for more efficient grating writing. The passive version of this fiber, the PS-GSF-3/125, is designed as a bridge fiber for use with its active counterpart. The company also has released a single-mode, erbium-doped fiber, the SM-ESF-7/125, which offers an alternative to making nonpolarized lasers and amplifiers with short device lengths and high pump conversion efficiency.