The single-mode core of this fiber is co-doped with erbium and ytterbium. It is then surrounded by a silica cladding and covered with a low-index protective coating. The resulting double clad fiber is used for single-mode fiber lasers and amplifiers operating in the 1540 to 1565 nm range.
The fiber enables fiber lasers and amplifiers with good beam profile characteristics, high wall plug efficiencies, compact footprints, superior reliability, and maintenance-free operation. It also accommodates high energies during pulsed operation and at high repetition rates.