Extractable energy from erbium-ytterbium co-doped pulsed fiber amplifiers and lasers

Abstract

An analytic model is developed for evaluating the extractable energy from high energy pulsed erbium-ytterbium co-doped fiber amplifiers and lasers. The energy extraction capabilities under the limitation of spurious lasing, due to amplified spontaneous emission (ASE), are mapped for various numerical apertures, single and multi transverse mode evolution and operating wavelengths. The model provides an assessment for the maximum pulse energy that can be extracted from a given erbium-ytterbium co-doped fiber. In addition, the model can be used to determine the repetition rate and optimal length, under which the laser source will be optimally operated in order to achieve a required extracted energy, without spurious lasing. The results show a clear advantage in using 915nm wavelength pump source over 975nm, at high average power operation, due to augmented 1μm ASE at 975nm pump wavelength, as a result of the Yb3+ population inversion.