This phosphosilicate fiber is ideal as a gain medium for lower power amplifiers or the pre-amplifier stage and is mainly used in a MOPA configuration of a pulsed fiber laser. On top of all the benefits found in a phosphosilicate fiber (high saturation energy, photodarkening-free performance and high absorption), this fiber shows easy single-mode operation and very low splice loss when matching with standard fibers such as HI 1060.