Jain S, Jung Y, May-Smith T C, Alam S U, Sahu J K, Richardson D J
Opt Express. 2014 Nov 17;22(23):29031-6. doi: 10.1364/OE.22.029031.
We experimentally demonstrate a few-moded cladding-pumped multi-element fiber amplifier, comprising 4 Er/Yb co-doped signal fibers and 1 multimode pump-delivery fiber all of which are drawn together in a common polymer coating, providing a total spatial path multiplicity of 12. An average WDM signal gain of 18.3 dB and differential modal gain of 1.1 dB were achieved in the spectral range of 1542-1560 nm.