scholarly journals In-band pumping avenue based high power superfluorescent fiber source with record power and near-diffraction-limited beam quality

Author(s):  
Jiangming Xu ◽  
Jun Ye ◽  
Hu Xiao ◽  
Jinyong Leng ◽  
Wei Liu ◽  
...  

High power superfluorescent fiber sources (SFSs), which could find wide applications in many fields such as middle infrared laser generation, Raman fiber laser pumping and spectral beam combination, have experienced a flourishing time in recent years for its unique properties, such as short coherence length and high temporal stability. The challenge for performance scalability of powerful SFS mainly lies on the physical issues including parasitic laser oscillation and modal instability (MI). In this contribution, by employing in-band pumping avenue and high-order transverse-mode management, we explore a high power SFS with record power, near-diffraction-limited beam quality and spectral manipulation flexibility. An ultimate output power of 3.14 kW can be obtained with high temporal stability and a beam quality of $M^{2}=1.59$ for the amplified light. Furthermore, the dynamics of spectral evolutions, including red-shifting of central wavelength and unsymmetrical broadening in spectral wings, of the main amplifier with different seed linewidths are investigated contrastively. Benefiting from the unique high pump brightness and high MI threshold of in-band pumping scheme, the demonstrated system also manifests promising performance scaling potential.

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 78
Author(s):  
Anye Wang ◽  
Jian Zhang ◽  
Shuai Ye ◽  
Xiaofei Ma ◽  
Baiyi Wu ◽  
...  

Single-crystal fibers (SCFs) have a great application potential in high-power lasers due to their excellent performance. In this work, high-quality and crack-free Yb3+:Lu3Al5O12 (Yb:LuAG) SCFs were successfully fabricated by the micro-pulling-down (μ-PD) technology. Based on the laser micrometer and the X-ray Laue diffraction results, these Yb:LuAG SCFs have a less than 5% diameter fluctuation and good crystallinity along the axial direction. More importantly, the distribution of Yb ions is proved to be uniform by electron probe microanalysis (EPMA) and the scanning electron microscope (SEM). In the laser experiment, the continuous-wave (CW) output power using a 1 mm diameter Yb:LuAG single-crystal fiber is determined to be 1.96 W, at the central wavelength of 1047 nm, corresponding to a slope efficiency of 13.55%. Meanwhile, by applying a 3 mm diameter Yb:LuAG SCF, we obtain a 4.7 W CW laser output at 1049 nm with the slope efficiency of 22.17%. The beam quality factor M2 is less than 1.1 in both conditions, indicating a good optical quality of the grown fiber. Our results show that the Yb:LuAG SCF is a potential solid-state laser gain medium for 1 μm high-power lasers.


Author(s):  
Jiaxin Song ◽  
Hanshuo Wu ◽  
Jun Ye ◽  
Hanwei Zhang ◽  
Jiangming Xu ◽  
...  

In this paper, we experimentally investigated the extreme frequency shift in high-power Raman fiber laser (RFL). The RFL was developed by using a pair of fiber Bragg gratings with fixed and matched central wavelength (1120 nm) combined with a piece of 31-m-long polarization maintaining (PM) passive fiber adopted as Raman gain medium. The pump source was a homemade high-power, linearly polarized (LP) wavelength-tunable master oscillator power amplifier (MOPA) source with ${\sim}25~\text{nm}$ tunable working range (1055–1080 nm). High-power and high-efficiency RFL with extreme frequency shift between the pump and Stokes light was explored. It is found that frequency shift located within 10.6 THz and 15.2 THz can ensure efficient Raman lasing, where the conversion efficiency is more than 95% of the maximal value, 71.3%. In addition, a maximum output power of 147.1 W was obtained with an optical efficiency of 71.3%, which is the highest power ever reported in LP RFLs to the best of our knowledge.


2015 ◽  
Vol 23 (13) ◽  
pp. 17138 ◽  
Author(s):  
Hanwei Zhang ◽  
Pu Zhou ◽  
Xiong Wang ◽  
Xueyuan Du ◽  
Hu Xiao ◽  
...  

2014 ◽  
Vol 915-916 ◽  
pp. 385-389
Author(s):  
Yuan Yuan Gu ◽  
Guo Xing Wu ◽  
Hui Lu ◽  
Jian Lin

Direct diode lasers have some of the most attractive features of any laser. They are very efficient, compact, wavelength versatile, low cost, and highly reliable. However, the full utilization of direct diode lasers has yet to be realized. This is mainly due their poor output beam quality. Because of this, direct diode lasers are typically used to pump other lasers such as bulk solid-state (rod and thin disk) and fiber lasers. An improvement of the wall-plug efficiency and Power density necessary can be achieved by beam shaping and beam combination such as polarization coupling. In this paper, using the beam shaping technology realize good beam quality and high wall-plug efficiency. Base on bars rated to 60 W and 57% conversion efficiency, vertically stacked arrays (twenty bars) of such configuration are demonstrated with rated to about 1200W. The beam quality of high-power high brightness 880 nm laser diode source is improved with beam shaping. Beam parameter product of 79. 3 mm mrad ×81. 2 mm mrad, electro-optical conversion efficiency of more than 45.8% and continuous output power of 1 kW are demonstrated. This laser can be directly applied to cladding, surface hardening and other fields.


1993 ◽  
Vol 29 (17) ◽  
pp. 1500 ◽  
Author(s):  
H. Po ◽  
J.D. Cao ◽  
B.M. Laliberte ◽  
R.A. Minns ◽  
R.F. Robinson ◽  
...  

1991 ◽  
Vol 27 (8) ◽  
pp. 661 ◽  
Author(s):  
H. Hamada ◽  
M. Shono ◽  
S. Honda ◽  
R. Hiroyama ◽  
K. Matsukawa ◽  
...  

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