Results are presented for high power (> 0.5 W) Yb3+ fibre lasers opera
ting at a wavelength of around 1120 nm pumped either by Nd:YAG (1.064
mum) or Nd:YLF (1.047 mum) lasers. The use of this laser as a single-w
avelength pump for a Tm3+ ZBLAN upconversion fibre laser is also demon
strated.