A method of transferring energy in an optical fiber structure is disclosed. This
method transfers energy from a cladding element of the fiber structure to a core
element of the fiber structure. The core element includes an active gain component
and an energy migration component. The cladding element, which surrounds the core
element, includes the energy migration component. The structure and method can
be utilized to provide either an optical fiber laser or an optical fiber amplifier.
The method includes the steps of providing a pump for producing the energy and
optically coupling the pump with the cladding element. The cladding element, including
the energy migration component, is then pumped with the energy produced by the
pump such that the energy is absorbed and stored in the cladding element by the
energy migration component. The method further includes the step of transferring
the energy stored in the cladding element to the core element by migration of the
energy within the energy migration component to the active gain component such
that the active gain component in the core element lases or provides gain.