Industrial COIL systems--part 1: laser beam delivery by fiber

First results of experimental and theoretical investigations related to an industrial application of oxygen-iodine laser (COIL) are reported. A developed calculative model determines a transmission factor of a laser emission at a set wavelength depending on the waveguide parameters, focusing system characteristics, and laser emission intensity angular distribution. Carried out investigations concerned with delivery of a laser emission power up to 1.6 kW via industrial quartz waveguides of 0.8- and 1 -mm- diameters and 3 and 10 meters long. It was shown that at optimal parameters of the delivery system the waveguide transmission is virtually independent of the diameter and bending radius and is equal to 0.90±0.02, which is in a good agreement with calculative results. The spatial distribution of the laser intensity at the waveguide input and output was measured. The far-field divergence at the 90%-level of the power was shown to increase approximately by 4 times when the laser emission is propagated through a quartz waveguide with a 800-mkm-diameter core and 3 m long.