Mid-infrared hollow fiber couplers
Fiber couplers based on hollow metallic fibers were designed and fabricated to branch and combine mid-infrared laser light with low loss. The fiber coupler was fabricated by side-polishing and bonding two hollow metallic fibers bent at an arbitrary curvature. The branching ratio is precisely aligned by the position shift amount of the two fibers in the optical axis direction. The fabricated coupler showed a branching ratio of 0 - 50% and an excess loss of less than 1 dB.
Univ. of Toyama (Japan)