Katsuki Suematsu

High bandwidth optical interconnection for densely integrated server

We developed optical interconnect technologies, i.e., an optical mid-plane, high-density connector, and a compact transceiver for future servers that enable high-bandwidth and dense integration. Using these technologies, 1500 optical connections and 37.5 Tb/s of bandwidth were built in a blade-server form factor.

Optical interconnect architecture for servers using high bandwidth optical mid-plane

We describe an interconnect architecture that utilizes high bandwidth optical mid-plane. Enabling technologies for high density optical mid-plane are discussed. We developed a prototype to determine the feasibility. The results showed proposed architecture is practical.

Development of MPO type 8-multicore fiber connector

We developed MPO type 8-MCF (56-core) connector. Rotational alignment with alignment member and absorption of protrusion difference using compressive strain were adopted. Fabricated 8-MCF connector demonstrated all core PC and connection loss <; 0.7 dB.

Development of small MT type 2-multicore fiber connector

We developed small MT type 2-MCF connector. PC condition for MT type MCF connector was studied theoretically and experimentally. Fabricated 2-MCF connector demonstrated return loss more than 46dB and connection loss less than 1.16dB.

Confirmation of Core Pitch Accuracy of Fiber Bundle Type Fan-Out for MCF

Core pitch measurement with σ≤0.147μm was achieved by developed precise measurement method for fiber bundle type fan-out (FBF). Accuracy of core pitch better than ±0.4μm was also confirmed for 7 and 19-core FBFs for MCFs.

MPO Type 8-Multicore Fiber Connector With Physical Contact Connection

We developed a MPO type 8-multicore fiber (MCF) connector using single mode 7-core MCF and realized physical contact (PC) with return loss more than 40 dB and low connection loss less than 0.85 dB in all 56 cores. To simplify the rotational alignment process for each MCF, we developed the rotational alignment method using alignment member and realized rotational alignment accuracy within ±1°. To reduce necessary pressing force for PC connection of all cores in all MCFs, we utilized compressive strain of MCF cladding for the absorption of height difference among MCFs and polishing for bare MCF to reduce necessary pressing force for a pair of MCFs. Fabricated 8-MCF connector demonstrated all cores PC with pressing force of 18 N.

No-polish elastic optical multifiber connector for optical interconnection

An elastic optical multifiber connector compatible with a standard mechanically transferrable connector was realized. The elastic connector has N-shape folded frame parts which are elastically deformable of 100 μm. Physical contact connections between no-polish fibers and a film-waveguide were confirmed. The average insertion loss of the cables terminated at one side with an elastic connector shows 0.16 dB which is almost same as those terminated at both ends with mechanical transferrable connectors. The durability for 250 times mating/demating tests in a mid-plane connector housing were also confirmed. Furthermore, the laser-cleaved fiber facets have smooth surfaces and convex shapes like those of polished connectors. Using the connector and the process, physical contact connections between no-polish fibers were achieved.

Development of low-cost polish-less optical multifiber backplane connector

We developed a novel low-cost polish-less elastically deformable optical multifiber backplane connector. The ferrule deformation and fibers buckling were enabled to cancel the variation in the lengths of unpolished cut fibers. We confirmed the physical contact connection between unpolished cut fibers in the ferrule and a polymer waveguide in a connector for polymer-waveguides connected with mechanical transfer connector (PMT) ferrule. The connection loss is almost the same as that between a conventional polished mechanical transfer (MT) ferrule and the PMT ferrule. We prepared a connector housing to mount the ferrules on a backplane/midplane. The insertion loss and return loss results in the housing show no degradations during 200 mating/demating tests, and there were no fiber breakages or damage to the waveguide core.

R=1mm 90°-Bent Multi-Mode Optical Fiber

We investigated the bending losses and the polarization dependent losses of 90° light beam deflection for multi-mode optical fibers (MMF) using small-radius 90°-bent optical fibers with low refractive index UV curable resin.

Bend insensitive small diameter fibers for optical interconnection systems

Bending loss insensitive small diameter fibers for optical interconnection systems using 1100 nm high-speed VCSELs are designed and fabricated. 90°-bending with 1 mm radius is achieved by fabricated 80 μm cladding fibers using stress-free bending technique.