Investigation Into the Influence of High-Power Optical Transmission on Fiber Withdrawal From Optical Connector

We investigated the influence of a high-power optical transmission on an optical connector by focusing on the fiber withdrawal phenomenon. Along with the curvature radius and the convex vertex eccentricity, fiber withdrawal is one of the key factors in obtaining good connections in single-core optical connectors that use a cylindrical ferrule. When the fiber fixed to the ferrule by adhesive, fiber withdrawal is generated by creep as the adhesive undergoes shear due to the temperature increase of the optical connector. In this paper, we examine the relationship between the optical loss power and fiber withdrawal in order to clarify the conditions leading to fiber withdrawal during high-power optical transmission. We confirm that the shear stress created by the axial compressive force deliberately imposed to achieve reliable physical contact in the optical connector greatly encourages fiber withdrawal. In addition, we clarify that fiber withdrawal under high-power optical transmission depends significantly on the initial fiber position in the connector plug, regardless of the connector temperature increase. We also investigate the long-term reliability of optical connectors for high-power optical transmission. We subject optical connectors to 90C, which corresponds to the glass transition temperature of the adhesive, for 500 hours, and measure the optical and mechanical properties. The measured values of both properties remain excellent, and we clarify that although some slight fiber withdrawal occurs during high-power optical transmission, optical connectors with zirconia ferrules do not allow the transmission performance to degrade.