Optical amplifiers overview

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 OPTICAL AMPLIFIERS:

 Below is the general form of an optical amplifier

 

 Types of OAs:

  1. Semiconductor optical amplifiers (SOAs) 
  2. Fiber Raman and Brillouin amplifiers 
  3. Rare earth doped fiber amplifiers (erbium – EDFA 1500 nm, praseodymium –PDFA 1300 nm)   

The most practical optical amplifiers to date include the SOA and EDFA types. New pumping methods and materials are also improving the performance of Raman amplifiers.

 
 Semiconductor Optical Amplifier (SOA) – similar to a laser cavity. Used as a discrete amplifiers. They can be integrated into arrays of amplifying switching and gating devices. Finding application in all optical 3R-regeneration systems
 
 
Rare Earth Doped Fiber Amplifier Characteristics:
Rare earth doped fiber amplifiers are finding increasing importance in optical communications systems. Perhaps the most important version is erbium doped fiber amplifiers (EDFAs) due to their ability to amplify signals at the low loss 1.55m wavelength range.
 
Raman amplification is based upon stimulated Raman scattering in which the photon induces inelastic scattering of the pump photon in the non-linear regime of the medium. This scattering generates another photon with lower frequency (and energy) while the energetic difference (and therefore the frequency difference) is passed to the vibration states of the medium. The main application of this effect is in the field of ultra-fast optics and in optical communications in the generation of all-band wavelength conversion and all-optical direct signal amplification.
 
 

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