Kun Peng

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.

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.

2kW (2+1) GT-wave fiber

We fabricated and reported on a (2+1) GT-wave fiber suitable for bidirectional pump method. 2.02 kW laser output with optical-to-optical efficiency of 67.8% was generated in bidirectional pump GT-wave fiber amplifier.

5kW GT-Wave Fiber

We fabricated and reported on a GT-wave fiber suitable for bidirectional pump method. 5.07 kW laser output with optical-to-optical efficiency of 74.5% was generated in bidirectional pump GT-wave fiber amplifier.

Yb-doped LMA fiber fabrication using chelate precursor doping technique

We report on the fabrication of a kW-level Yb-doped fiber by using chelate precursor doping technique. Lasing performance was tested up to 1 kW laser output with slope efficiency of 81.8%.

Halide gas-phase-doping technique to fabricate large-mode-area laser fiber

By using rare-earth-halide gas-phase-doping technique, we fabricated Yb-doped large-mode-area fiber preform. Yb concentration is of ~9500ppmw in core area and 951W@1064nm laser output was obtained with a slope efficiency of 83.3%.

Experimental investigation on laser performance of distributed side-pumping fiber amplifier

1+1 type distributed-side pumping active fibers were fabricated. Pumped with 976nm LD, over 1kW output power was achieved at 1064nm and 581W power was launched into the coupling unit via one port.