Akira Ohki

ParaBIT-1: 60-Gb/s-throughput parallel optical interconnect module

We previously proposed ParaBIT (parallel inter-board optical interconnection technology), and developed a prototype front-end module, called ParaBIT-0, with a total throughput of 28 Gb/s (700 Mb/s/spl times/40 ch). Aiming at higher throughput, lower cost, and further miniaturization, we are now developing a version, called ParaBIT-1, which is designed to achieve a total throughput of 60 Gb/s (1.25 Gbit/s/spl times/480-ch). To achieve a compact and high-throughput module, we developed a new compact high-density packaging structure and cost-effective optical coupling system for ParaBIT-1. This packaging structure enabled us to reduce the volume of ParaBIT-1 to 9 cc, which is about one-third that of ParaBIT-0 (25 cc). The optical coupling system consists of a new structure 24-fiber BF (bare fiber) connector whose main parts are made of molded plastic and a 24-channel optical coupling component using new polymeric optical waveguide film. The optical coupling component is composed of a 24-ch waveguide film with 45/spl deg/ mirrors and the 24-fiber BF connector interface, and can be assembled by passive alignment. The film has high thermal stability to allow soldering reflow processes, and is fabricated by direct photo-patterning. ParaBIT-1 met the design target of 1.25 Gb/s per channel.

An optical coupling technique for parallel optical interconnection modules using polymeric optical waveguide films

ParaBIT (parallel inter-board optical interconnection technology) is promising for high-throughput interconnections in advanced switching and computer systems. We have developed a new optical coupling technique for ParaBIT modules using polymeric optical waveguide films. This technique provides good optical coupling in ParaBIT modules, and is also very useful for multi-channel optical coupling. In this paper, we describe the design, structure, and characteristics of this optical coupling technique.

Fabrication of a parallel inter-board optical interconnection module using transferred multichip bonding

ParaBIT (parallel inter-board optical interconnection technology) is a promising candidate for large-capacity board-to-board interconnection. In ParaBIT module assembly, a new multichip diebonding technique is needed, because precise optical device chip mounting is required for efficient optical coupling at the E/O (electric/optic conversion) and O/E (optic/electric conversion) interfaces. In this paper, we have proposed a new technique, called TMB (transferred multichip bonding), for the precise mounting of multiple optical device chips. We have also described the detailed procedures of TMB and demonstrated its use in ParaBIT module assembly.

A 100-Gb/s throughput ATM switch MCM with a 320-channel parallel optical I/O interface

For an ATM switch system, we have developed a 100-Gb/s input/output (I/O) throughput optical I/O interface ATM switch multichip module (MCM) that has 320-ch optical I/O ports. This MCM is fabricated using ceramic (MCM-C) technology and very-small highly-parallel O/E and E/O optical converters. It uses 0.25-/spl mu/m complementary metal oxide semiconductors (CMOS) ATM switch large scale integrations (LSIs) and has a total I/O throughput of up to 160 Gb/s. A prototype module with total I/O throughput of 100 Gb/s has been partially assembled using eight optical I/O interface blocks, each composed of a 40-ch O/E converter and a 40-ch E/O converter; the data rate per channel is from dc to 700 Mb/s. Using this module we developed an optical I/O interface ATM switch system and confirmed the operation of the optical interface.