This paper reports the design and characteristics of an aerial optical drop cable incorporating electric power wires, which was developed for a new π-system. The new system is called the power supply HUB π-system, in which commercial AC electric power is received at a central location of several optical network units (ONUs), and is distributed to each ONU by the aerial optical/electric drop cable. We describe the requirements for the cable, which guarantee a 20-year lifetime. We designed the cross-sectional structure of the cable, based on system requirements and operation requirements, and determined the strength wire type and diameter, based on the optical fiber failure prediction theory and a cable strain requirement. We confirmed that the cables, manufactured as a trial, have stable characteristics, which satisfy the above requirements. The optical/electric drop cables will be introduced in autumn 1999.

A method for constructing a compact non-blocking, large matrix-size, optomechanical switch is proposed. It can be switched arbitrarily by disconnecting and reconnecting ferrules on the matrix board. A 250500, 25-mm-ferrule-pitch, 800W855D945H (mm) switch is fabricated. Although the space above the board is densely packed with many ferrule-terminated-fibers, because of the way in which they are arranged and the control of their length, there is no discernible excess loss due to fiber bending.

This paper describes the induction heating system designs for spliced fiber reinforcement and the reinforcement performances. In the case of the reinforcement method using hot-melt adhesive, it is necessary to give the reinforcing assembly the precise temperature distribution. For this reason, the power transfer efficiency from the power source to the work object of the reinforcing assembly was investigated under practical induction heating conditions. Furthermore, the effect of each coil of the induction coils on the magnetic intensity generated in the part of the work object opposite the induction coils was examined. The transient temperature distribution of the work object could be obtained through simulation by designing the proper numbers of turns of wire, the setting positions of the induction coils and the dimension of electric power at a power source. The simulation results agreed approximately with the measured temperatures of the work objects. Through the proper thermal designs, the sandwich and heat-shrinkable-sleeve reinforcements were completed within 1 min., 30 sec. with good performances by supplying less than 26, 12-W of electric powers, respectively.

A new reinforcement machine using induction heating has been developed for heat-shrinkable-sleeve reinforcement method. Through the proper thermal design of the heating system, the reinforcement of a single-spliced fiber was completed in 30s with good performance by supplying 200 Ws of electric power output.

In mechanical splice technology, loss change during temperature cycling is mainly caused by fiber slippage or shift at the interface between fibers and fiber clamping substrates. The upper limit of the fabrication accuracy of the fibers and substrates restricts the total number of fibers in a splice. To overcome this, we propose a novel fiber clamping method using the elasticity of the substrate surface. We clamp the fibers more strongly at the fiber clamping ends, where the fibers need a greater friction force than around the butt-joint, to hold them in position. Taking the case of an 8-fiber ribbon splice, we compared linear marks on the substrates with the boundary linewidth curves for the onset of slippage. We achieved an insertion loss change of less than 0.1 dB during a temperature cycling test in accordance with Telcordia Technologies test specification. When we clamp fibers using the plasticity of the substrate surface, we can also reduce the required fabrication accuracy. However, insufficient accuracy causes an unexpected loss change due to fiber shift as a result of a plastic flow on the substrate surface in contact with the fibers.

A non-blocking optomechanical matrix switch has been developed that is assembled using cassettes as units. Switching can be accomplished between two ferrule-terminated-fiber groups by automatic disconnection and reconnection. The fabricated 100100, 3.1-mm-ferrule-pitch, 710W490D500H (mm) switch exhibits a mean insertion loss of 0.78dB in the 1.31-µm wavelength.

A fully automatic, high-speed splicing machine for optical fiber ribbons has been developed to construct high-count optical cable lines in subscriber loops. Design procedure and detail performance of this machine is discussed in this paper. The developed machine achieves an average splice loss of less than 0.1 dB and a splicing time of about 2 min. for multi-mode five-fiber ribbons.