Blue up-conversion Tm~(3+)-doped fiber laser pumped by a multiline Raman source

摘要

We report laser oscillation at 481 nm when pumping a Tm~(3+)-doped fluorozirconate fiber by two Raman-generated signals at 1117 and 1175 nm. A superior efficiency was achieved when pumping with both lines. For example, the conversion efficiency was 20% when pumping with 83 mW of 1117 nm and reached 33% when copumping with 29 mW of 1175 nm. As higher powers of the copumping signal were applied, a powerful amplified spontaneous emission at ～790 nm started to compete with 481 nm. The slope efficiency evolved from 16% to 48% when pumping with a simpler, noncontrolled Raman source that provided a single- to multi wavelength evolving spectrum.