Development of super high-density optical circuits using downsized fibers, flame-retardant tape fiber, and multi-fiber optical connectors

Due to increased transmission capacity, light-based transmission formats (optical fibers) are used extensively in metro networks and other systems, not only for networking but also as a component in transmission equipment between boards, on a single board, and between chips. Wiring on boards and other small spaces requires tight bending of the cable, but the SM fiber currently used has a bending radius limit of R30 mm. To meet this demand, we reduced the outer diameter of the optical fiber from 125 μm to 80 μm, and by making the MFD 6.4 μm, we developed a fiber that can be housed at R5 mm. Also, we decreased the diameter of the sheathed optical fiber by half - from a diameter of 250 μm down to the extreme limit of 125 μm. Furthermore, we developed a connector that allows connection with existing flame retardant tape fiber. The final result is a cable with twice the density of conventional products. In this report, we discuss various characteristics of three items that we developed: a small diameter optical fiber, flame retardant tape fiber, and a high-density optical connector that can be injection-molded for easy mass production.