Low-noise and gain-flattened fluoride-based Er3+-doped fibre amplifier pumped by 0.97 μm laser diode

The authors demonstrate a gain-flattened Er³⁺-doped fluoride fibre amplifier with low noise amplification characteristics which employs 0.97 μm laser diode pumping. Excellent flat amplification is achieved with an average signal gain of 12.5 dB and a gain excursion of <1.0 dB with a noise figure of 4.7±0.2 dB for an 8 channel WDM signal in the 1532-1560 nm wavelength region. The authors confirm that an Er³⁺-doped fluoride fibre can be excited effectively to the ⁴I_11/2 level by shifting the pump wavelength from 0.98 to 0.97 μm