SPring-8 X-Ray Micro-Tomography Observations of Zirconium Inclusions in CO $_{2}$ Laser Fusion Splice for Single Mode Optical Fibers

Laser fusion splicing has been realized for the simple splicing of optical fibers in a small board area, and for accommodating the increasing number of optical fibers that must be mounted on a board. For the splicing, zirconia ceramics are conventionally used to fabricate V-groove substrates because of their high machining performance. In this study, the existence of zirconium inclusions between the spliced optical fibers could be clarified with SPring-8 micro-computed tomography (SP-μCT) for the first time. The large inclusion size was found to increase the splicing loss. Moreover, the average splicing loss could be reduced from 0.18 dB to 0.15 dB by the adoption of a cleaning process to remove the zirconium inclusions that originate from the V-groove substrate used for the fiber.