ParaBIT: Parallel optical interconnection for large-capacity ATM switchingsystems

We have been working on a project called ParaBIT (for parallel inter-board optical interconnection technology) to achieve large-capacity switching sys tems. The ParaBIT module being developed as the first step in this project is a front-end module with 40 channels providing throughput of 28 Gb/s, cos t-effectiveness and compactness. To realize the module, this project has de veloped five novel technologies: (1) 850-nm 10-ch Vertical-cavity Surface-e mitting laser (VCSEL) arrays as very cost-effective light sources, (2) new high-density multiport bare fiber connectors that do not need a ferrule and spring, (3) passive optical alignment using polymeric optical waveguide fi lm with a 45-degree mirror for coupling to the optical array chips and the waveguide, (4) transferred multichip bonding to mount optical array chips o n a substrate with a positioning error of only a few micrometers, and (5) s imple electronic circuits with a fixed-decision-level receiver and an APC-l ess transmitter, and low power consumption. Experimental results show that the design targets of throughput of 700 Mb/s per channel and a compact and cost-effectiveness structure were met. Thus, ParaBIT is a promising technol ogy for large-capacity switching systems.