Browsing by Subject "Power lasers"
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Item Open Access 915 nm pumped 1018 nm Yb-doped all-fiber high power fiber laser system(Institute of Electrical and Electronics Engineers Inc., 2019) Midilli, Yakup; Efunbajo, O. Benjamin; Şimşek, Bartu; Ortaç, BülendFibers lasers have attracted great attention in the last decades and the power scaling has reached tens of kW levels. Especially with the tandem pump configuration, pumping the active medium with a pump laser light instead of a diode laser, has made a breakthrough and so many research has been conducted about 1018 nm fiber laser systems [1]. Decreasing the quantum defect, the slope efficiency could be increased up to 90 % levels; on the other hand, due to the emission cross section of the Ytterbium (Yb), to operate the laser in the 1018 nm wavelength region is very challenging because of the presence of the ASE about the 1030 nm region. However, in the literature by using 976 nm pump diodes multi-hundred watts level 1018 nm fiber lasers could be demonstrated [2, 3].Item Open Access An all-fiber ultra-low numerical aperture high power fiber MOPA system with an output power above 500 W(Institute of Electrical and Electronics Engineers Inc., 2019) Midilli, Yakup; Ortaç, BülendOptical fiber technology has been developed dramatically in the last two decades. Especially, the invention of the Large Mode Area (LMA) fibers has made a great impact, and consequently the power scale of the fiber lasers started to increase exponentially [1]. However, at a certain point this increase has been saturated due to the non-linear effects such as Stimulated Raman Scattering (SRS) and Thermal Modal Instability (TMI). Therefore, a new approach has been proposed to mitigate these so called problems by decreasing the numerical aperture (NA) of the LMA active fiber so that it behaves like an intrinsically single mode fiber. In the literature, an active fiber having ultra-low (<; 0.04) NA, is proposed [2, 3] in 2009; and finally, the highest power, which is 4.3 kW, was demonstrated in 2017 [4]. However, all of these works based on free space orientation. In this letter, we demonstrate all-fiber and monolithic version of the high power low NA fiber laser system based on an Yb-doped active fiber having 26 μm/410 μm core/cladding diameters respectively with a NA of 0.032 which has also been verified experimentally.