Effective suppression of stimulated Raman scattering in half 10  kW tandem pumping fiber lasers using chirped and tilted fiber Bragg gratings

2019 ◽  
Vol 7 (2) ◽  
pp. 167 ◽  
Author(s):  
Meng Wang ◽  
Zefeng Wang ◽  
Le Liu ◽  
Qihao Hu ◽  
Hu Xiao ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Fiber Lasers ◽  
Stimulated Raman Scattering ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Effective Suppression ◽  
Stimulated Raman

scholarly journals Fabrication of kW-level chirped and tilted fiber Bragg gratings and filtering of stimulated Raman scattering in high-power CW oscillators

2019 ◽  
Vol 7 ◽  
Author(s):  
Kerong Jiao ◽  
Jian Shu ◽  
Hua Shen ◽  
Zhiwen Guan ◽  
Feiyan Yang ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Power Systems ◽  
High Power ◽  
Stimulated Raman Scattering ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
The Core ◽  
Hydrogen Molecules ◽  
Hydroxyl Compounds ◽  
Stimulated Raman

Suppression of stimulated Raman scattering (SRS) by means of chirped and tilted fiber Bragg gratings (CTFBGs) has become a key topic. However, research on high-power systems is still lacking due to two problems. Firstly, after the inscription, there are a large number of hydroxyl compounds and hydrogen molecules in CTFBGs that cause significant heating due to their strong infrared absorption. Secondly, CTFBGs can couple Stokes light from the core to the cladding and the coating, which causes serious heating in the coating of the CTFBG. Aimed at overcoming these bottlenecks, a process that combines constant-low-temperature and variable-high-temperature annealing is used to reduce the thermal slope of the CTFBG. Also, a segmented-corrosion cladding power stripping technology is used on the CTFBG to remove the Stokes light which is coupled to the cladding, which solves the problem of overheating in the coating of the CTFBG. Thereby, a CTFBG with both a kilowatt-level power-carrying load and the ability to suppress SRS in a fiber laser has been developed. Further, we establish a kW-level CW oscillator to test the CTFBG. Experimental results demonstrate that the power-carrying load of the CTFBG is close to 1 kW, the thermal slope is lower than $0.015\,^{\circ }\text{C}/\text{W}$, and the SRS suppression ratio is nearly 23 dB.

scholarly journals Fabrication of chirped and tilted fiber Bragg gratings and suppression of stimulated Raman scattering in fiber amplifiers

2017 ◽  
Vol 25 (2) ◽  
pp. 1529 ◽  
Author(s):  
Meng Wang ◽  
Yujing Zhang ◽  
Zefeng Wang ◽  
Junjie Sun ◽  
Jianqiu Cao ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Stimulated Raman Scattering ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Fiber Amplifiers ◽  
Stimulated Raman

scholarly journals Mitigation of stimulated Raman scattering in kilowatt-level diode-pumped fiber amplifiers with chirped and tilted fiber Bragg gratings

2019 ◽  
Vol 7 ◽  
Author(s):  
Meng Wang ◽  
Le Liu ◽  
Zefeng Wang ◽  
Xiaoming Xi ◽  
Xiaojun Xu
Keyword(s):  
Raman Scattering ◽  
Fiber Lasers ◽  
Stimulated Raman Scattering ◽  
Beam Quality ◽  
Average Power ◽  
Fiber Amplifiers ◽  
Maximum Output ◽  
Power Scaling ◽  
Diode Pumped ◽  
Stimulated Raman

The average power of diode-pumped fiber lasers has been developed deeply into the kW regime in the past years. However, stimulated Raman scattering (SRS) is still a major factor limiting the further power scaling. Here, we have demonstrated the mitigation of SRS in kilowatt-level diode-pumped fiber amplifiers using a chirped and tilted fiber Bragg grating (CTFBG) for the first time. The CTFBG is designed and inscribed in large-mode-area (LMA) fibers, matching with the operating wavelength of the fiber amplifier. With the CTFBG inserted between the seed laser and the amplifier stage, an SRS suppression ratio of ${\sim}10~\text{dB}$ is achieved in spectrum at the maximum output laser power of 2.35 kW, and there is no reduction in laser slope efficiency and degradation in beam quality. This work proves the feasibility and practicability of CTFBGs for SRS suppression in high-power fiber lasers, which is very useful for the further power scaling.

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