Naoki Matsushima

A 25-Gb/s × 4-Ch, 8 × 8 mm 2 , 2.8-mm thick compact optical transceiver module for on-board optical interconnect

A 25-Gb/s × 4-ch optical transceiver module was developed. To obtain a compact module, CMOS analog front-end ICs, a lens integrated connector, and small LGA package was applied. The module demonstrated 25-Gb/s error-free transmission.

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.

A compact 25-Gbit/s × 4ch optical interconnect module with straddle-shaped optical and electrical interface

A compact 25-Gbit/s × 4-ch embedded optical module (EOM) composed of a straddle-shaped optical and electrical interface was fabricated and evaluated. The fabricated EOM provides highly efficient optical coupling and large optical-coupling tolerance, and it successfully demonstrated 25-Gbit/s error-free optical transmission. These optical performance results indicate that the fabricated compact EOM can be applied for on-board and rack-to-rack optical interconnections with high transmission density.

A 25 Gb/s × 4-ch, 8 × 8 mm small size optical transceiver module for optical interconnection

A 25 Gb/s × 4-ch, 8 × 8 mm2 optical transceiver module for optical interconnection has been developed. To obtain a compact optical module suitable for chip-to-chip interconnection, a lens integrated connector, a small low temperature co-fired ceramic (LTCC) package, and a precise lens assembling technology were used. Experimental results showed that the proposed module can achieve 25 Gb/s error free transmission.

A high-density 300-Gbit/s parallel optical interconnect module with efficient optical sub-assembly techniques

A high-density 300-Gbit/s (25-Gbit/s × 12-ch) parallel optical-interconnect module (OIM) was fabricated by using an efficient, newly developed optical sub-assembly (OSA) techniques. The OIM module provides high heat dissipation and high optical-coupling efficiency. Furthermore, the fabricated OIM successfully demonstrated 25-Gbit/s error-free multimode transmission.

10 Tb/s scale optical interconnection system using high-density optical wiring

The bandwidth of information and communication technology (ICT) systems is increasing and is predicted to reach 10 Tb/s and over. However, an electrical interconnect cannot achieve such bandwidth because of its density limits. To solve this problem, we propose a high-density optical backplane, which consists of a fiber cassette and eleven optical backplane connectors. The fiber cassette accommodates 768 optical fibers. The backplane connector housing can mount eight 48-fiber mechanically transferable (MT)-ferrules. Optical backplane is 89 mm wide and 13 mm thick; therefore, equipment can secure a sufficient area for cooling while achieving a 9.6-Tb/s aggregate bandwidth. It also eases assembly and testing. The insertion loss of the backplane including the two connectors results in 1 dB or less. We demonstrated an optical interconnection system using the optical backplane, which exhibited error-free transmission between boards up to 25.8 Gb/s. We also propose an optical connector using lensed ferrules instead of MT-ferrules. Due to the introduction of the lensed ferrules, the spring force of the connector can be reduced to 1/5 that with an MT-ferrule. The optical connector can be mounted in the front panel of ICT system equipment. These optical wiring components enable the development of ICT systems with bandwidth exceeding 10 Tb/s.

A high-density 300-Gbit/s parallel optical interconnect module with efficient thermal dissipation characteristics

A high-density 300-Gbit/s (25-Gbit/s × 12-ch) parallel optical interconnect module (OIM) with a high efficiency heat radiation structure was fabricated using a thermal via structure. The prototype OIM successfully demonstrated 25-Gbit/s error-free multimode transmissions, and the optical device temperature was less than 80°C.

High wiring density Cu-polyimide thin film multilayer circuit which is realized by the vertical plated small via

A fabrication process for Cu-polyimide thin film multilayer circuit has been developed for advanced multichip module. The multilayer circuit realizes a high wiring density circuit by applying Cu studs which are deposited by electroplating using the guide patterns made of thick positive photoresist, photosensitive polyimide for insulating layers which has low reactivity against Cu, and a polishing process for planarizing dielectric layers. This paper reports on the structure of the circuit and on the thin film process technology.

Compact pitch-conversion (fan-in/out) polymer optical waveguide with graded-index circular cores for high-bandwidth-density on-board interconnects

We fabricate 12-ch. compact pitch-conversion multimode polymer optical waveguides with graded-index (GI) circular cores using the Mosquito method, and demonstrate that GI cores maintain the low optical loss and crosstalk even if steep curved channel patters are formed in order to realize a compact device.

Optical interconnect technologies for high-bandwidth ICT systems

The bandwidth of information and communication technology (ICT) systems is increasing and is predicted to reach more than 10 Tb/s. However, an electrical interconnect cannot achieve such bandwidth because of its density limits. To solve this problem, we propose two types of high-density optical fiber wiring for backplanes and circuit boards such as interface boards and switch boards. One type uses routed ribbon fiber in a circuit board because it has the ability to be formed into complex shapes to avoid interfering with the LSI and electrical components on the board. The backplane is required to exhibit high density and flexibility, so the second type uses loose fiber. We developed a 9.6-Tb/s optical interconnect demonstration system using embedded optical modules, optical backplane, and optical connector in a network apparatus chassis. We achieved 25-Gb/s transmission between FPGAs via the optical backplane.