The erbium-doped fiber amplifier (EDFA) is the most deployed fiber
amplifier as its amplification window coincides with the third
transmission window of silica-based optical fiber.
Two bands have developed in the third transmission window – the
Conventional, or C-band, from approximately ***5 nm – ***5 nm, and
the Long, or L-band, from approximately ***0 nm to ***0 nm. Both of
these bands can be amplified by EDFAs, but it is normal to use two
different amplifiers, each optimized for one of the bands.
