Efficient light coupling from semiconductor lasers into tapered hemispherical-end fibers

The light from a semiconductor laser is coupled efficiently into a tapered hemispherical-end optical fiber obtained by drawing in an arc discharge. The maximum coupling efficiency of 83 percent is achieved for the graded index fiber having a 60-µm core diameter. Permissible transverse displacement for a 1-dB decrease of coupling is about 19 µm.