The modular and growable photonic ATM switch architecture described in this paper uses both time-division and wavelength-division multiplexing technologies, so the switch capacity can be expanded in both the time and frequency domains. It uses a new implementation of output buffering scheme that overcomes the bottleneck in receiving and storing concurrent ultra fast optical cells. The capacity in one stage of a switch with this architecture can be increased from 32 gigabits per second to several terabits per second in a modular fashion. The proposed switch structure with output channel grouping can greatly reduce the amount of hardware and still guarantee the cell sequence.

This paper describes the use of optical interconnections in switching systems and discusses our recent achievements in this area. Switching system interconnections are classified based on their application layers. The evolution of optical interconnections in switching systems in discussed in terms of such system requirements as cost, size, and throughput. Recent achievements are discussed: an optical inter-module connector, a free-space digital switch, and a large-capacity optically intra-connected ATM switch.

High-speed NRZ-DMI coder and decoder monolithic ICs employing novel circuits suitable for high-speed operation have been developed using Si bipolar technology. They operate up to 1.8 Gb/s with a 3.6 GHz clock frequency. Power dissipations of the coder and decoder are 872 mW and 1333 mW, respectively.

This paper proposes a new, high-speed method of filling in the contours of alpha-numeric characters to produce correct binary image patterns. We call this method the improved edge-fill method because it improves on a previously developed edge-fill method. Ambiguity of the conventional edge-fill method on binary images are eliminated by selecting fill pixels from combinations of Freeman's chain code, which expresses contour lines. Consequently, the areas inside the contour lines are filled in rapidly and correctly. With the new method, the processing time for character image generation is reduced by ten to tewnty percent over the conventional method. The effectiveness of the new method is examined in experiments using both Arabic numerals and letters from the Roman alphabet. Results show that this fill method is able to produce correct image patterns and that it can be applied to alpha-numeric-character contour filling.

This paper reports a high-speed time division switching system using GaAs ICs. It also describes high-speed switching technologies including the fabrication of a 4-channel time division switch, a multi/ demultiplexer and peripheral circuit ICs, each having more than a 2 Gb/s throughput capability. In addition, such key factors as synchronous LSI operation, optimum circuit board designing and LSI packaging are presented. Finally it reports a great success in High Definition TV (HDTV) time division switching operation.