Broad-bandwidth pulse amplification to the 10-microJ level in an ytterbium-doped germanosilicate fiber

The saturation characteristics of pulse amplification in an ytterbium-doped fiber are studied. The highest pulse energy obtained is 12 microJ at a repetition rate of 1 kHz. Even with gain narrowing, the fiber is capable of amplifying the bandwidth of 100-fs pulses at 1 microm.