COIL Fiber Transmission for Material Cutting Applications

Abstract

The 10kW-class Chemical Oxygen-Iodine Laser (COIL) device of DLR was used for demonstration of efficient power coupling into a commercial fiber optic system (HIGHYAG, Berlin) modified for 1.315 µm radiation. Transmission investigations were performed with different intra-cavity apertures of the stable COIL resonator to match the outcoupled laser beam to the fiber optic system. The transmitted power through the 20 m long fiber with core diameter of 1000 µm exceeded 6 kW during a typical 8 s test run of the laser. The highest transmitted power amounts to 11 kW, the highest value reported in literature. The transmission ratio was above 90%. Samples of metal and non-metal materials were cut by using nitrogen as processing gas. The materials were selected with regard to their application in the contaminated area of nuclear power plants. The results of the cutting experiments were used in theoretical models for extrapolation of the cutting data. Scaling studies were performed to estimate achievable cutting depth with COIL systems of higher laser power.