Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
Lecture 8: Laser amplifiers
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Real coherent <strong>amplifiers</strong><br />
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Real coherent <strong>amplifiers</strong> deliver a gain and phase shift that are frequency<br />
dependent. The gain and phase shift determine the amplifier’s transfer<br />
function.<br />
For a sufficiently large input amplitude, real <strong>amplifiers</strong> generally exhibit<br />
saturation, a form of nonlinear behavior in which the output amplitude<br />
does not increase in proportion to the input amplitude.<br />
Saturation introduces harmonic components into the output, provided that<br />
the amplifier bandwidth is sufficiently broad to pass them.<br />
Real <strong>amplifiers</strong> also introduce noise, s.t. a random fluctuating component<br />
is present at the output, regardless of the input.<br />
An amplifier may therefore be characterized by the following features:<br />
• Gain<br />
• Bandwidth<br />
• Phase shift<br />
• Power source<br />
• Nonlinearity and gain saturation<br />
• Noise<br />
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