A fiber amplifier for amplifying an optical signal, comprising a pump
energy source capable of emitting energy at a pump wavelength: optical
apparatus for transmitting the optical signal, the optical apparatus
having a plurality of discrete portions, each discrete portion comprising
a length of optical fiber and first and second components disposed at
first and second respective locations and configured to substantially
prevent energy having an intermediate wavelength in the discrete portion
from entering other discrete portions of the optical apparatus; and a
plurality of waveguides, each waveguide coupled to the pump energy source
and to one of the plurality of discrete portions, each waveguide for
providing energy at the pump wavelength from the pump energy source to
its corresponding discrete portion, thereby increasing an intensity of
light at the discrete portion's intermediate wavelength.