This limits the wavelength range of the laser. A novel class of lasers, known as upconversion lasers, can violate this rule. In this work, we investigate a particular type of upconversion, avalanche upconversion, which yields output light with a wavelength shorter than that of the pump. In particular, we characterized a thulium doped fluorozirconate laser. This material was studied in a fiber geometry due to its long interaction length and high pump confinement.
Fibers are excellent media for laser beams, showing low losses and efficient heat dissipation.
These and other characteristics make fiber very useful in telecommunications networks. Thulium-doped fluorozirconate fiber lasers offer high efficiency, high gain and also can deliver high power. Our objective consisted in describing the properties of the output beam when pumped with a ytterbium-doped single mode continuous wave laser around 1060 nm. The output signal showed upconversion lasing around 810 nm and was characterized according to its slope efficiency, spatial profile, and spectral profile.