<title>Future of nonoxide fiber lasers: searching for the commercial application</title>

Abstract

Fiber lasers offer several advantages over bulk solid-state lasers because they can achieve both high efficiency and fair output power. Still, the use of those silica fiber lasers is limited to very few particular applications like broadband ASE source and pulsed fiber lasers. But, since non-oxide fibers open a broad wavelength range not accessible via rare-earth doped silica fiber nor semiconductor lasers, several niches should be available. In this paper, a comparative study of performances and commercial readiness of both oxide and non- oxide fiber lasers will be done. Effectively, non-oxide fiber laser developers are confronted to several fundamental (photo- induced loss) and technical challenges (splicing, moisture, handling in general). For example, the availability of the right pump laser wavelength lags behind any serious commercial applications. Fortunately, efficient up-conversion process helps access visible to UV wavelength range with commercial IR and near-IR pumps. Also, optimization and prediction of the performance must rely almost solely on experimental validation because the numerical simulation of non-oxide glass is very complex. In particular, for up-conversion lasers, one must consider and more important, know both the emission and absorption cross-sections of 5 to 10 energy levels. Nevertheless, we will review some promising applications coming from sensors system, RGB visible sources, telecommunication applications and some special LIDAR systems that can use double-clad fiber geometry for more efficient pumping and higher power output.