EFFICIENT AMPLIFICATION IN THE 1ST TELECOMMUNICATIONS WINDOW

Thulium-doped fluorozirconate fibre can be used as an efficient amplif ier over the wavelength range 800-815 nm in the first telecommunicatio ns window. A small-signal gain of 23 dB has been achieved at 805 nm wi th 50 mW of launched pump power at 780 nm. The fibre used for this dem onstration had a core diameter of 3.5 mum, numerical aperture 0.16 and thulium ion concentration approximately 800 ppm by weight. The backgr ound loss of the fibre was measured to be less than 0.1 dB m-1. These results suggest that a high gain 800 nm amplifier employing an AlGaAs diode-pumped thulium-doped fluorozirconate fibre can now be made.