Rika Nomura

7.2-Tb/s compact optical backplane using ribbon fiber sheet and high-density connector

A compact optical backplane was developed, and a ribbon fiber sheet and high-density connector were used to reduce the cost and wiring area. A bandwidth of 7.2-Tb/s was achieved within a 288 × 53 mm2 area inside the network equipment.

Effect of adherend surface morphology on adhesive strength

UV-curing acrylic adhesives characterized by relatively high elastic modulus at room temperature and high Tg are prone to provide inadequate adhesive strength because of the stress concentration at the interface between the adhesive and the adherend. We used two types of metal adherend (Zn), one with a flat surface structure and the other with a sawtooth surface structure, to verify the effect of the surface morphology of the adherend on the initial adhesiveness and reliability [1]. The results showed that, by employing the sawtooth structure for the adherends surface morphology, the initial adhesive strength increased significantly regardless of the adhesive type, and that the fracture mode shifted from the dominant interfacial failure mode to the mixed mode of interfacial failure accompanied with cohesive failure. On the other hand, the adhesive strength after reliability tests had different tendencies depending on the adhesive types. It was found that, for adhesives having a higher crosslink density, coupled with the effect of the sawtooth structure, the rate of deterioration accelerated to cause the adhesive strength to decrease significantly, and that the fracture mode transitioned only to the interfacial fracture mode over storage time under reliability test storage conditions of 60°C/90%RH. Accordingly, to simultaneously achieve higher reliability and increased adhesive strength, it is essential to apply the sawtooth structure for the adherends surface morphology and use adhesives having a lowered crosslink density.

3.3-Tb/s compact optical fiber package using pre-formed optical fiber

We developed a compact optical fiber package for rack-to-rack transmission in information communication technology. Using pre-formed optical fiber instead of optical fiber strands and ribbon fiber, we achieved a reduction in the routing area and protection of the optical fiber. We fabricated a prototype mock-up board with optical modules and achieved a bandwidth of 3.3 Tb/s and an area of 4500 mm2. We confirmed a good transmission performance board-to-board with 5 m of optical cable at 25 Gb/s (PRBS: 231-1).