Yuwei Li

5kW GTWave fiber amplifier directly pumped by commercial 976nm laser diodes.

With home-made fiber perform and special fiber drawing & coating technique, a new-type of (3 + 1) GTWave fiber theoretically designed for bi-directional pump method, was successfully fabricated and justified of integrating multi-kW pump energy from commercial 976nm laser diodes. This (3 + 1) GTWave fiber amplifier demonstrated uniform absorption of pump light and easy thermal management characteristics along the whole fiber length. This amplifier is capable of simultaneously aggregating 5.19kW pump power at 976nm and finally generating 5.07kW laser output at 1066.5nm with an optical-to-optical efficiency of 74.5%, the first publically-reported multi-kW GTWave fiber directly pumped with commercial 976nm laser diodes to the best of our knowledge. No power roll-over was found at 5kW level and further power scaling can be expected with more pump power. The results indicate that GTWave fiber is a competitive integrated fiber device to collect enough pump energy from low-cost commercial laser diodes for multi-kW fiber laser development.

Yb-Doped Aluminophosphosilicate Laser Fiber

By using modified chemical vapor deposition system combined with chelate precursor doping technique, we report on the fabrication and characterization of Yb-doped aluminophosphosilicate (Al2O3-P2O5-SiO2) laser fiber. Based on a master oscillator power amplifier laser setup and pumped directly by 976 nm laser diodes, 3.1 kW laser at ~1064 nm was achieved with a slope efficiency of 78.4%. Benefiting from codoped Al and P, the laser output power showed no evidence of roll-over. The linear fitting of the output power versus the pump power shows the potentiality for further power scaling. The results indicate that chelate precursor doping technique is a competitive method for rare-earth-ion-doped fiber preform fabrication, and aluminophosphosilicate host material has potentiality to develop multi-kW level laser fibers.

KW-level commercial Ce/Yb Co-doped aluminosilicate fiber

To investigate the laser performance of Ce/ Yb-codoped aluminosilicate (Al2O3-SiO2) binary glass fiber, we took commercial Nufern-20/400-9M fiber as a research object. 0.95 kW laser output power at 1066 nm with an optical-to-optical efficiency of 83.3% was achieved at fiber laser amplifier stage. Beam quality of Mx2 and My2 is 1.56 and 1.68 at 0.95 kW, respectively. The results indicate Nufern-20/400-9M fiber may be suitable

kW-level commercial Yb-doped aluminophosphosilicate ternary laser fiber

Based on a master oscillator power amplifier configuration, laser performance of commercial Nufern-20/400-8M Ybdoped aluminophosphosilicate ternary laser fiber was investigated. Pumped by 976 nm laser diodes, 982 W laser output power was obtained with a slope efficiency of 84.9%. Spectrum of output was centered at 1066.56nm with 3dB bandwidth less than 0.32 nm, and the nonlinearity suppression ratio was more than 39dB. Beam quality of Mx2 and M2y were 1.55 and 1.75 at 982 W, respectively. The laser performance indicated that Nufern-20/400-8M Yb-doped aluminophosphosilicate ternary laser fiber is highly competitive for industry fiber laser use.

Fluorescence Distorted Absorption Phenomenon of Yb-doped Double-clad Laser Fiber

The influence of fluorescence on the absorption measurement of Yb-doped double-clad fiber was studied. The results show that the 976 nm fluorescence leads to a linear but slight decrease of absorption coefficient at 976 nm.

6kW GTWave Fiber Amplifier

We fabricated and reported a GTWave fiber amplifier that allowed for 8.43 kW aggregated pump power. GTWave fiber presented 6 kW laser output with optical-to-optical efficiency of 69.8% without any evidence of roll-over.