3D Nanoporous Silica Rods for Extra-Large-Core High-Power Fiber Lasers

Recent advances in high-power fiber lasers have imposed several pairs of higher requirements on fiber materials, such as larger fiber core/higher homogeneity and higher doping level/lower numerical aperture. However, these characteristics conflict with each other in silica fibers and are almost impossible to reconcile by traditional fiber preparation technologies. Here, we developed 3D nanoporous silica rods based on glass phase separation technology to address these conflicting requirements. Benefiting from uniformly distributed nanopores, nanoporous silica glass exhibits remarkable performance in its core diameter, doping level, refractive index controlling, and optical homogeneity. These properties make nanoporous silica glasses very suitable as a fiber core material and greatly distinguish them from other fiber materials. We have prepared a typical Yb3(+)-heavily doped fiber with a core diameter of 80 mu m and an ultralow numerical aperture of 0.029. The fiber exhibits an excellent laser performance with a slope efficiency of 79.5% for 600 W laser emission at 1080 nm in a 0.85 m length fiber. Our study will make 3D nanoporous silica glass emit new energy in fiber materials and boost the advancement of high-power fiber lasers.