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Master Oscillator Power Amplifier

Acronym: MOPA

Definition: a laser system consisting of a seed laser and a laser amplifier for boosting the output power

German: Laser-/Verstärker-Kombination

Categories: lasers, optical amplifiers

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The term master oscillator power amplifier (MOPA) refers to a configuration consisting of a master laser (or seed laser) and an optical amplifier to boost the output power. A special case is the master oscillator fiber amplifier (MOFA), where the power amplifier is a fiber device. In other cases, a MOPA may consist of a solid-state bulk laser and a bulk amplifier, or of a tunable external-cavity diode laser and semiconductor optical amplifier.

Although a MOPA configuration is in principle more complex than a laser which directly produces the required output power, the MOPA concept can have certain advantages:

However, the MOPA approach can also have disadvantages:

MOPA architectures are also used for pulsed laser sources. In that case, the amplifier may be used as a reservoir of energy. If a pulse from the seed laser extracts a significant fraction of the stored energy, the effect of gain saturation is relevant: the amplifier gain drops during the pulse. This can lead to a deformation of the temporal pulse shape. In some cases, the pulse shape from the seed source is tailored so as to obtain the desired pulse shape after amplification.

See also: optical amplifiers, master oscillator fiber amplifier, amplifier noise, The Photonics Spotlight 2008-09-24, The Photonics Spotlight 2008-12-16, The Photonics Spotlight 2010-03-22
and other articles in the categories lasers, optical amplifiers


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