Analysis of noise performance in rare-earth-doped fiber optical amplifiers in the 1.3-um and 1.55-um wavelength bands

摘要

Abstract: A comprehensive analysis of noise in rare-earth doped fiber optical amplifiers has been carried out using both the minimum noise figure (NF) and the noise figure with amplified spontaneous emission (ASE) noise spectral density. According to these different analytical methods, we have analyzed the noise performance for different applications. We found that the method calculating the noise figure with ASE spectral density gave more accurate correlation with experimental results. Furthermore, we confirmed that the NF in erbium-doped fiber amplifiers (EDFA), with pumping at 980 nm wavelength, is 2 dB less than that at 1480 nm, and the 3 dB quantum limit can also be obtained. The noise figure in concatenated EDFAs is approximately 8 dB after transmission through 9000 km. the noise figures in cascaded amplifiers, with the signal-spontaneous beat noise dominating, are almost the same for several stages. The noise figure in a distributed amplifier is more sensitive to the doping concentration. The 3 dB quantum-limited noise figure can also be obtained in a praseodymium-doped fluoride fiber optical amplifier operating at a signal wavelength of 1.3 $mu@m. !17