| Abstract: | The gain and noise figure can be improved by periodic bending of an erbium-doped fiber. Bending of 5.4 m at the beginning of an erbium-doped fiber results in a reduction of noise figure, a gain increment, and a reduction of forward amplified spontaneous emission of 5.1, 3.6, and 1.5 dB for a 1533-nm small signal; 4.0, 1.9, and 2.1 dB for a 1550-nm small signal; and 2.7, 0.9, and 1.8 dB for a 1560-nm small signal (-40 dBm), respectively. In addition, the periodic bending can operate an erbium-doped fiber amplifier at quantum-limited noise and enables its operation to be more stable. |
