Optical Amplifier - Laser Amplifiers - Gain Saturation

Gain Saturation

Gain is achieved in a DFA due to population inversion of the dopant ions. The inversion level of a DFA is set, primarily, by the power of the pump wavelength and the power at the amplified wavelengths. As the signal power increases, or the pump power decreases, the inversion level will reduce and thereby the gain of the amplifier will be reduced. This effect is known as gain saturation – as the signal level increases, the amplifier saturates and cannot produce any more output power, and therefore the gain reduces. Saturation is also commonly known as gain compression.

To achieve optimum noise performance DFAs are operated under a significant amount of gain compression (10 dB typically), since that reduces the rate of spontaneous emission, thereby reducing ASE. Another advantage of operating the DFA in the gain saturation region is that small fluctuations in the input signal power are reduced in the output amplified signal: smaller input signal powers experience larger (less saturated) gain, while larger input powers see less gain.

The leading edge of the pulse is amplified, until the saturation energy of the gain medium is reached. In some condition, the width (FWHM) of the pulse is reduced.

Read more about this topic:  Optical Amplifier, Laser Amplifiers

Other articles related to "gain saturation, gain":

Erbium-doped Waveguide Amplifier - Laser Amplifiers - Gain Saturation
... Gain is achieved in a DFA due to population inversion of the dopant ions ... or the pump power decreases, the inversion level will reduce and thereby the gain of the amplifier will be reduced ... This effect is known as gain saturation – as the signal level increases, the amplifier saturates and cannot produce any more output power, and therefore the gain reduces ...

Famous quotes containing the words saturation and/or gain:

    In the twentieth century, death terrifies men less than the absence of real life. All these dead, mechanized, specialized actions, stealing a little bit of life a thousand times a day until the mind and body are exhausted, until that death which is not the end of life but the final saturation with absence.
    Raoul Vaneigem (b. 1934)

    To gain a reputation for virtue, grieve over those you injure.
    Mason Cooley (b. 1927)