Energy transfer

Physics

Kinetics

Laser

Rate equation

Optics

Engineering

Atomic physics

Fiber laser

Materials science

Lasing threshold

Erbium

Quantum mechanics

Clamping

Optoelectronics

Ytterbium

Doping

Mechanical engineering

Optics Express

Conventional models of Er/Yb co-doped fibers assume all ytterbium ions are equally involved in the energy transfer with erbium ions, governed by a singular transfer rate. This would predict output power clamping once ytterbium parasitic lasing starts, contrary to the observations that the output continued to grow albeit at a slower rate. One study explained this using elevated temperature at high powers. Our study, however, shows that elevated temperature and mode-dependent effects only play insignificant roles. A new model is developed based on the existence of isolated ytterbium ions, which can explain all the observed experimental behaviors.

Modeling Er/Yb fiber lasers at high powers