Abstract
Mid-infrared fiber laser technology has advanced dramatically over the last 20 years. In this review, we
describe high-power mid-infrared lasers and mid-infrared ultrashort pulse lasers using fluoride-glass fiber
gain media. Diode-pumped Er 3+-doped fiber lasers with a wavelength of around 2.8 μm have
reached continuous-wave output power that exceeds 40 W. Mid-infrared fiber lasers using Ho 3+ and
Dy 3+ ions have also achieved considerably higher output. Ultrashort pulse laser technology with fluoride-
glass fiber gain media has been created within the decade and is developing into various research
based on nonlinear optics. These laser technologies are paving the way for the development of powerful
mid-IR sources for cutting-edge fields in industry, medicine, and science.
