Abstract
We report the performance characteristics of a diode-pumped Tm 3+, Ho3+-doped silica fiber laser as a function of the dopant concentrations. We show, albeit indirectly, that the rates of energy transfer upconversion (ETU) are significantly increased when the Tm3+ concentration and hence rates of cross relaxation (CR) are increased. The net result of ETU is a reduction in the 3F4 population of Tm3+ and heating of the fiber as a result of the large rates of multiphonon emission from the higher lying energy levels of Ho3+. Fibers with low Tm3+ concentrations display the highest slope efficiencies and lowest thresholds, with 95% of the Stokes efficiency limit being achieved. CR, therefore, cannot be completely harnessed as a mechanism to enhance the rate of upper laser level excitation in Tm3+, Ho 3+-doped silica fiber lasers.
Original language | English |
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Pages (from-to) | 1885-1887 |
Number of pages | 3 |
Journal | IEEE Photonics Technology Letters |
Volume | 18 |
Issue number | 17 |
DOIs | |
Publication status | Published - 1 Sept 2006 |
Externally published | Yes |
Keywords
- Energy transfer
- Fiber laser
- Ho
- Midinfrared
- Slope efficiency
- Tm