Cross relaxation and energy transfer upconversion processes relevant to the functioning of 2 μm Tm3+-doped silica fibre lasers

Stuart D. Jackson*

*Corresponding author for this work

Research output: Contribution to journalArticle

219 Citations (Scopus)

Abstract

We identify the cross relaxation (CR) and energy transfer upconversion (ETU) processes that are important to the operation of Tm3+-doped silica fibre lasers using the slope efficiency measured from a number of diode-pumped Tm3+-doped silica fibre lasers displayed as a function of Tm3+ concentration and Al3+:Tm3+ concentration ratio. These assessments are correlated with minimum energy mismatch between the initial and final states of each energy transfer process determined from the Stark level assignments relevant to a number of Tm 3+-doped crystals. The CR process 3H4, 3H63F4, 3F 4 is highly probable in silica because of the strong spectral overlap between the 3H43F4 fluorescence spectrum and 3H63F 4 absorption spectrum. The endothermic phonon-assisted CR process 3H4, 3H63H 5, 3F4, however, may have a non-negligible contribution to the total cross relaxation. The exothermic phonon-assisted ETU process 3F4, 3F43H5, 3H6 may be the major contributor to quenching of the lifetime of the 3F4 multiplet particularly when the degree of clustering is large even though the 3F43H5 excited absorption band is outside the transparency range for silica glass. The endothermic phonon-assisted ETU process 3F4, 3F 43H4, 3H6 is also shown to have a non-negligible contribution to the quenching of the 3F4 multiplet. These results have been combined to produce a Tm3+-doped silica fibre laser that produces a slope efficiency of ∼74%; the highest yet reported for a ∼2 μm fibre laser.

Original languageEnglish
Pages (from-to)197-203
Number of pages7
JournalOptics Communications
Volume230
Issue number1-3
DOIs
Publication statusPublished - 15 Jan 2004
Externally publishedYes

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