Toshifumi Hosoya

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 /spl mu/m to 80 /spl mu/m, and by making the MFD 6.4 /spl mu/m, 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 /spl mu/m down to the extreme limit of 125 /spl mu/m. 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.