Large Giant and Free-Running Laser Pulse Energy and Power Densities Through Optical Fibers

Abstract

The surface threshold damage levels (STDL) and coupling efficiencies, ε, (ratio of output-to-input energy) have been determined for single and multiple optical fibers of five manufacturers. For giant laser pulses of 30 nsec duration, the largest STDL's were observed in American Optical Company fibers for single and multiple laser shots with values of 48.2 and 31.6 J/cm2, respectively. For free-running laser pulses of 100 µsec duration, the largest STDL was observed in Corning Glass Works fibers for single laser shots with a value of 4.66 kJ/cm2. For multiple laser shots increased energy caused the initial damage sites in the binding or fiber cladding materials to increase in size and cause new sites in these materials at lower STDL's than for single laser shots. The giant laser pulses caused the most severe surface damage. There is no evidence to suggest that the observed decrease in e was caused by other than the increase in damage to the input surface of the fibers.