hi naazira,
EDFA, SOA and OA,
EDFA and SOA have there usual meaning which we all know(ie. erbium doped fiber amplifier and semiconductor optical amplifier,)
there amplifier have both simulation and practical importance.
where OA refers to optical amplifier , and acts as black box which has function of amplifiyiny optical pulse.
these have only simulation importance, however for practiacl application we can design amplifier of same characteristics as that of OA.
with regards