Two-dimensionally arrayed optical-fiber splicing with a CO_2 laser

The splicing of a bundle of optical fibers arrayed in a matrix form by using a CO(2) laser has been demonstrated. After end preparation of multimode graded-index fibers with a 60-microm core diameter and a 150-microm outer diameter, the fibers were aligned in an 8 x 3-layer matrix form so that their axes were parallel and their endfaces were in contact. Using a specially designed laser-beam focusing system, fusion splicing was carried out successively from the first to third layer. Each butted fiber pair on the layer was fusion spliced one after another by passing the fibers through the beam focal point of the CO(2) laser. The average splice loss for five trials of splicing (120 splices) was 0.18 dB, and this showed that repeated radiation of the CO(2) laser beam onto the optical fibers during splicing did not increase splice loss as long as the energy density to which spliced joints were exposed was lower than 5 x 10(2) W/cm(2).