High power ytterbium fiber lasers at extremely long wavelengths by photonic bandgap fiber technology
Yb-doped fiber laser operating at the long-wavelength edge (11501200nm) of the broad gain spectrum has been investigated for yellow-orange sources. Power scaling in this region has been recently achieved by Yb-doped solid-core photonic bandgap fibers, in which the Yb gain profile is engineered by the sharp-cut, bandpass distributed filtering and therefore amplified spontaneous emission in the high-gain region (10301100nm) is strictly inhibited. We have recently demonstrated amplification with as high as 167W output power and 61% slope efficiency at 1178nm. The novel gain profiling technique by photonic bandgap fibers can be extended to other rare-earth doped fibers.
ytterbium fiber laser photonic bandgap fiber distributed filtering amplified spontaneous emission fiber amplifier