Amplification and lasing at 1350 nm in a neodymium doped fluorozirconate fibre

The gain spectrum of a 0.5 m length of neodymium doped fluorozirconate multimode fibre has been measured in the 1350 nm wavelength region. The peak of the gain spectrum occurs at 1354 nm whilst the peak of fluorescence is at 1320 nm, suggesting the presence of excited state absorption of lasing photons at shorter wavelengths. Lasing characteristics at 1050 nm and 1354 nm are also reported.