Numerical Design of $4\,\mu {\rm m}$-Class Dysprosium Fluoride Fiber Lasers
| Autor: | Matthew R. Majewski, Stuart D. Jackson |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Journal of Lightwave Technology. 39:5103-5110 |
| ISSN: | 1558-2213 0733-8724 |
| DOI: | 10.1109/jlt.2021.3080296 |
| Popis: | In this report we show using numerical simulations that, with judicious choice of pump and fiber parameters, that it is possible to achieve lasing at wavelengths longer than ${4}\,{\mu {\rm m}}$ from the $^6H_{11/2}\rightarrow ^6H_{13/2}$ laser transition of Dy ${^{3+}}$ using an indium fluoride (InF $_3$ ) glass host. The key issue for this transition is the short lifetime of the upper laser level of ${1.25}\,{\mu {\rm s}}$ relative to the long lifetime of the lower laser level which is ${640}\,{\mu {\rm s}}$ . Whilst continuous wave (CW) cascade lasing at ${4.4}\,{\mu {\rm m}}$ and ${3.3}\,{\mu {\rm m}}$ could be achieved, the large pump power requirement at threshold of $>$ 30 W is impractical. Pulsed pumping combined with gain switching, however, offers a viable alternative. We calculate that 200 ns, ${160}\,{\mu {\rm J}}$ pump pulses launched into InF $_3$ fiber could deliver ${15}\,{\mu {\rm J}}$ output at ${4.4}\,{\mu {\rm m}}$ . Scaling of average output power is constrained by population buildup in the lower laser level. Boosting the output power by quenching this lower level lifetime using OH $^{-1}$ or Tb ${^{3+}}$ co-dopants are explored as ways to overcome this limitation. |
| Databáze: | OpenAIRE |
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