Design considerations for short-wavelength operation of 790-nm-pumped Tm-doped fibers

Tm-doped 790-nm-pumped silica fiber lasers are excellent candidates for producing emission at <1.95 microm, but achieving efficient operation at these wavelengths requires careful attention to fiber design because of the characteristic three-level reabsorption effects. We present a discussion of methods for mitigation of these effects and two high-efficiency systems that are capable of producing up to 70 W at <1.92 microm.