Method and apparatus for high power optical fiber injection and alignment

An apparatus for controlling injection of a high power beam into an optical fiber, said apparatus comprising:

• a vision system for generating a signal representative of a focus spot on an optical fiber injection end, said vision system including an infrared viewer axially aligned with an injection end of the optical fiber, and a charge coupled camera coupled to said infrared viewer;
• a high speed vision processor coupled to said vision system;
• an x-y-z stage controller coupled to said high speed vision processor;
• and
• an optical fiber holder coupled to said x-y-z stage controller, said holder including means for engaging the optical fiber and x-y-z axis stages.

A method for controlling injection of a high power beam into an injection end of an optical fiber, the beam forming a focus spot on the optical fiber injection end, the fiber and beam being axially aligned along a z-axis, said method comprising the steps of:

• determining a focal length (f) of a focus lens being used to focus the beam on the fiber end, a laser beam quality (BQ), and a beam diameter (D);
• calculating an optimum spot size (ss);
• comparing a present focus spot size with the optimum spot size;
• and
• adjusting the position of the optical fiber injection end along the z-axis when a difference exists between the present focus spot size and the optimum focus spot size and until the present and optimum focus spot sizes are substantially equal.