| 摘要 |
PURPOSE:To manufacture comparatively easily a titled coupler, and also to reduce an insertion loss by interposing a plate-like lens array between plural input/output fibers and a mixing rod. CONSTITUTION:A lens array 6 and 8 which have arrayed lenses (f2/f1=b/a at the time of focal distances f1, f2) formed by arraying two lenses whose focal distance is different, in a co-focus, in the same period as an array of a fiber are installed between an input/output fiber group 5 and 9, and a cylindrical mixing rod 7. Therefore, an image of an end face 12 of a fiber core 10 is formed on a focal plane 13, and a magnification becomes b/a, therefore, an image forming surface 6b becomes equivalent to that which has arrayed a fiber having no clad 11 in a dense structure, and a light which is made incident to a clad part does not exist. In this way, it is unnecessary to thin a clad layer of the fiber, a fiber bundle can be manufactured comparatively easily, also a loss of a light which is made incident to the clad part is eliminated, and also the loss becomes extremely small by making a light incident efficiently to the fiber. |
