Use of Tapered Optical Fibers to Improve the Power Handling Capacity of Fiber Delivery System

The experiment on high power Nd:YAG laser pulses delivery by tapered fibers is reported. For a 15 ns pulse at 1064 nm wavelength, the maximal transmission energy of the tapered fiber is 2-3 times higher than of a traditional one. Laser-induced damage experiment on ten tapered fibers with different lengths and taper ratios is carried out. The results show all the damaged modes are fragmentation of output surfaces as a result of electric breakdown. It is also found the tapered fibers have the capability of spatial beam smoothing, and the longer tapered fiber has more strength to smooth beam.