Incoherent combination of fiber lasers using a collimating and focusing optical system in fiber-based laser fusion

The incoherent combination of fiber laser beams using a collimating and focusing optical system in fiber-based laser fusion is theoretically and numerically studied. The propagation of the fiber lasers passing through the optical system is analyzed by the ABCD law. The super-Gaussian fitting is performed to study the synthetic intensity profile near the focal spot quantitatively. The intensity profile of the combination beam is dependant on the defocusing distance, the number of the fibers, the separation of the fibers, and the beam expansion ratio of the collimating system.