407 W specially-designed fiber laser at 1018 nm using a gain fiber with a low core/cladding ratio of 20/400 μm

Abstract

In this paper, two monolithic 1018 nm Yb-doped fiber laser systems-one as an oscillator (OSC) and another as a specially-designed amplifier (SDA)-are investigated using 20/400 μm Yb-doped fibers (YDF). 394 W of output power and a slope efficiency of 39.4% was obtained from the OSC setup. The SDA setup resulted in 407 W of output power with a slope efficiency of 39.9%, which is the highest reported output power via the 20/400 μm YDF. The beam quality factor M 2 is also measured to be ~1.5 for both setups. Considerations regarding the gain fiber length were taken into account so as to suppress any detrimental effects such as ASE and self-pulsing. The output power behavior of both setups indicate that further power scaling would be possible.

A high power 1030 nm ytterbium doped fiber laser with a near diffraction limited quality using a 20/400 μm active fiber

“…In other words, using YDFs longer than the optimum length leads to emergence of the ASE and the upper level population peaks in some points inside the cavity which causes fiber fracture. This is the phenomenon that has been seen several times before when laser systems with long active fibers operates at high pump powers [14,19]. The active fiber length in this laser was set to be 7.3 m which leads to over 700 W of pure 1030 nm output power with no sign of ASE and the slope efficiency of about 77%.…”

“…Parasitic leasing at the selected wavelength can be destructive when pumping power increases. In this case, the active fiber can easily be damaged and fractured (which was seen in the producing process of the YDFL reported in [19]). In figure 3, output power, alongside the 1030 nm output signal power and the ASES are illustrated versus the YDF length.…”

Towards Ultimate High-Power Scaling: Coherent Beam Combining of Fiber Lasers

“…Tandem pumping refers to a technique in which high-brightness lasers are implemented as pumping sources. Owing to its unique potential for power scaling, it has been achieved great attention in the last decade [19,[86][87][88][89][90][91][92][93][94][95]. In 2010, IPG photonics corporation reported the first 10 kW level single-mode fiber laser via the TP scheme by utilizing fortyseven 270 W YDFLs operating at 1018 nm as pumping sources [96].…”

Towards Ultimate High-power Scaling: Coherent Beam Combing of Fiber Lasers

“…Tandem pumping refers to a technique in which high brightness lasers are implemented as pumping sources. Owing to its unique potential for power scaling, it has been achieved great attention in the last decade [19,[86][87][88][89][90][91][92][93][94][95]. In 2010, IPG photonics corp. reported the first 10 kW level single-mode fiber laser via TP scheme by utilizing forty-seven 270 W YDFLs operating at 1018 nm as pumping sources [96].…”

“…To suppress these deleterious effects, shortening the fiber length and using the high core/clad diameter ratio fibers are utilized. There has been ongoing research on producing high power 1018 nm fiber laser with diffraction-limited beam quality, to date, the highest output power of the YDFLs operating at 1018 nm fiber laser has been reported by Yan et al, as 1150 W [89,[91][92][93][94][95]. Although the highest record for achievable output power via TP scheme is predicted to be 52 kW [18], to date it has reached 20 kW [13].…”