EFFICIENT AND LOW-NOISE GAIN-FLATTENED DOUBLE-PASS L-BAND ERBIUM-DOPED FIBER AMPLIFIER

摘要

A new double-pass long-wavelength-band erbium-doped fiber amplifier with enhanced noise figure characteristics is demonstrated by adding a short length of forward pumped erbium-doped fiber (EDF) in front of the double-pass amplifier. By adding 7 m of EDF, the amplifier achieves a flat-gain output at about 34.2 dB with a gain variation of less than 1.3 dB at the wavelength region 1568-1598 nm. The corresponding noise figures vary from 5,0 to 5.7 dB, which is improved by 1.7 to 7.5 dB over the flat-gain region, as compared to that of the conventional double-pass amplifier. This new amplifier with high gain and low noise figure can be useful, as an inline amplifier in a wavelength division multiplexing transmission system.