APPARATUS AND METHOD FOR SOFT FOCUSING ENERGY INTO AN OPTICAL FIBER ARRAY

摘要

A method and apparatus for coupling laser energy into an optical fiber employs a laser (12) with a concave reflector (16) and a planar reflector (18), a plano-convex focusing lens (22) and an optical fiber array (28). A divergent laser beam (20) is emitted from the laser and is focused to a beam waist (24) by the plano-convex lens (22). Within the beam waist (24) exists a soft focal plane (26) wherein the laser energy is relatively homogeneous across the beam's cross section. An optical fiber array (28) is placed within the beam waist (24) such that the soft focal plane substantially matches the size and shape of the proximal end of the optical fiber array (28). Thus, laser energy is coupled to the optical fiber array (28) at the soft focal plane (26) within the beam waist (24) at a fluence level below the fluence damage threshold of the optical fiber array (28) and in a relatively homogeneous fashion across the cross section of the optical fiber array (28).