M. Heck, J.-C. Gauthier, A. Tünnermann, R. Vallée, S. Nolte and M. Bernier, “Long period fiber gratings for the mitigation of parasitic laser effects in mid-infrared fiber amplifiers,” Opt. Express 27, 21347-21357 (2019).
A concept to mitigate parasitic lasing in mid-IR fiber amplifiers using a single long period fiber grating is shown. Using tightly confined ultrashort laser pulses at 800 nm, a grating was directly inscribed into the core of an erbium doped fluoride glass fiber showing a strong attenuation down to −27 dB at desired wavelength. The concept reveals great potential to improve the average output power and attainable spectral range of low repetition rate in-amplifier supercontinuum generation.