• Most optical amplifiers amplify incident light through stimulated emission. An optical amplifier is nothing but a laser without feedback. Optical gain is achieved when the amplifier is pumped optically or electrically to achieve population inversion. Optical amplification depends on-
    • Frequency (or wavelength) of incident
    • Local beam
  • 8.1.1 shows basic operation of optical amplifier.
  • The external pump source energy is absorbed by the electrons in the active

medium. The electrons shifts to the higher energy level producing population inversion. Photons of incoming signal triggers these excited electrons to lower level through a stimulated emission process, producing amplified optical signal.

Amplifier Types

  • The optical amplifiers can be classified into two main
  1. Semiconductor optical amplifier (SOA).
  2. Doped fiber amplifier (DFA).
    • Both the types stimulated emission