In order to connect the MCF, not only a floating mechanism is required, but also a precise alignment of the rotation angle around the fiber axis. The Oldham coupling is a mechanism that satisfies these contradictory conditions and has long been used in the field of mechanical engineering. The function of this coupling is to transmit the rotation angle accurately even if shaft eccentricity occurs, but conversely, shaft eccentricity occurs even if it does not rotate, so it is possible to meet the necessary conditions for MCF connectors.
The first practical optical connector for MCF was the MU-type MCF connector developed in Japan in 2012 (Figure 1). By applying Oldham's coupling mechanism, positioning accuracy, including rotation angle, is maintained. It has the property that the connection loss does not fluctuate even when a tensile load is applied to the cable. The SC-type MCF connector was developed in 2019 to achieve the same principle with a simplified structure (Figure 1). The practical application of optical connectors to optical communication networks using MCF is progressing.
