Performance Benefits of 1860 nm vs. 1940 nm Pumping of Holmium-doped Fibres with Significant Ion Pairing

We report a first investigation of the performance of single clad Ho-doped fibres as a function of both ion pairing and pump wavelength. Our report shows that 1860 nm yields a significant performance advantage over 1940 nm pumping for representative Ho-doped fibres with a wide range of ion pairing. We find that our simulations when compared with experiment yield an accurate value for the degree of ion pairing. Our simulations are confirmed by experimental data.