Last updated on 02/1/2023
Noise figure is a parameter used to measure the amount of noise added to a signal as it is amplified in an optical fiber amplifier.
In an optical fiber amplifier, the signal passes through a gain fiber, where it is amplified by stimulated emission. However, the amplifier also adds its own noise, which is a combination of thermal noise, shot noise, and ASE noise.
The noise figure is defined as the ratio of the output signal-to-noise power ratio (SNR) to the input SNR, and it is expressed in dB. A lower noise figure indicates that less noise is added to the signal by the amplifier, resulting in a higher signal quality.
In optical communication systems, it is important to keep the noise figure as low as possible to ensure that the signal quality is maintained over long distances.