Abstract
In this article, we demonstrate great potential of lightly-erbium(Er3+)-doped ZrF4 fiber in efficient power scaling at ∼2.8 μm, when excited at ∼1.7 μm. Core-pumped by a random Raman fiber laser at 1.69 μm, the 1.5 mol.% Er3+-doped ZrF4 fiber in a F-P cavity has experimentally yielded an output power of >6 W at 2.783 μm with a slope efficiency of up to 58.4% (with respect to the absorbed pump), close to its Stokes limit of 60.7% (1.69/2.783). To our knowledge, this is the highest efficiency of Er3+-doped ZrF4 fiber lasers in the mid-infrared. Further power scaling is only limited by the current pump power. Based on the validated numerical model, the dominant role of the excited state absorption (ESA) process (i.e.,
$^4{\mathrm{I}}_{13/2}{ \to }^4{\mathrm{I}}_{9/2}$
) in exciting efficient ∼2.8 μm laser has been highlighted, and the resonant ground state absorption process (i.e.,
$^4{\mathrm{I}}_{15/2}{ \to }^4{\mathrm{I}}_{13/2}$
) is also essential. The simulation results indicate that the pump wavelength closer to the ESA peak can yield a higher slope efficiency. In addition, heat load analyses via numerical modeling reveals that the
$^4{\mathrm{I}}_{9/2}{ \to }^4{\mathrm{I}}_{11/2}$
multiphonon relaxation is the main heat source of the system. By taking fiber optical damage limit into account simultaneously, a high-power lightly-Er3+-doped ZrF4 fiber laser arrangement has been proposed, which theoretically enables 100-W-class output under a slope efficiency of >50% and a relatively low heat load.
PDF Article
Cited By
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
Contact your librarian or system administrator
or
Login to access Optica Member Subscription