TY - JOUR N2 - The paper deals with spectral and lasing characteristics of thulium-doped optical fibers fabricated by means of two doping techniques, i.e. via a conventional solution-doping method and via a nanoparticle-doping method. The difference in fabrication was the application of a suspension of aluminum oxide nanoparticles of defined size instead of a conventional chloride-containing solution. Samples of thulium-doped silica fibers having nearly identical chemical composition and waveguiding properties were fabricated. The sample fabricated by means of the nanoparticle-doping method exhibited longer lifetime, reflecting other observations and the trend already observed with the fibers doped with erbium and aluminum nanoparticles. The fiber fabricated by means of the nanoparticle-doping method exhibited a lower lasing threshold (by ~20%) and higher slope efficiency (by ~5% rel.). All these observed differences are not extensive and deserve more in-depth research; they may imply a positive influence of the nanoparticle approach on properties of rare-earth-doped fibers for fiber lasers. L1 - http://www.czasopisma.pan.pl/Content/114308/PDF/14_981-986_01280_Bpast.No.67-5_03.02.20.pdf L2 - http://www.czasopisma.pan.pl/Content/114308 PY - 2019 EP - 986 DO - 10.24425/bpasts.2019.130883 KW - optical fiber KW - fiber laser KW - thulium KW - aluminum oxide KW - nanoparticles KW - solution doping KW - nanoparticle doping A1 - Kasik, I. A1 - Kamradek, M. A1 - Aubrecht, J. A1 - Peterka, P. A1 - Podrazky, O. A1 - Cajzl, J. A1 - Mrazek, J. A1 - Honzatko, P. VL - No. 5 DA - 31.10.2019 T1 - Thulium-doped optical fibers for fiber lasers operating at around 2 µm SP - 981 UR - http://www.czasopisma.pan.pl/dlibra/publication/edition/114308 T2 - Bulletin of the Polish Academy of Sciences Technical Sciences ER -