Abstract: A data process system has a plurality of stations or terminals linked to a star coupler over cables comprising separate sending and receiving transmission lines, the cable shield being connected to system ground. To minimize bit error rate when a station is powered down, the transmitting differential amplifier at each terminal station is connected between a bias voltage and a virtual ground created by a pair of diodes connected in parallel, their anodes being connected to a voltage source through a current limiting resistor, the cathode of one diode being connected to system ground, the cathode of the other diode being connected to one side of the transmitting amplifier to define the virtual ground. To further enhance noise rejection, a balanced differential network is connected to the outputs of a transistor pair at the amplifier output to the differential wire transmission line.

Abstract: A data processing system having a plurality of stations and an optical transmission bus linking the stations. The bus includes two transmission lines carrying optical signals in opposite directions so that two stations may communicate simultaneously. A passive optical coupler module couples each station to the two transmission lines. The optical coupler module includes a silicon substrate having suitably formed grooves and recesses for mounting single fiber waveguide segments, tapered waveguides, each for directing the optical signal on either of two waveguide segments to a single optical path, and optical beam splitters, each for splitting a portion of the optical signal on a waveguide segment for each of two other waveguide segments.

Abstract: An optically linked distributed data processing system having a plurality of stations and first and second transmission lines associated with each station. The first transmission line carries optical signals to its associated station and the second transmission line carries optical signals from its associated station. An active optical coupler module couples each first transmission line to every second transmission line. The coupler module includes a tapered waveguide for directing the optical signals from each of the first transmission lines to a single optical path, an optical detector for converting the optical signals to electrical signals, an amplifier for amplifying the electrical signals. In one embodiment a single optical source converts the amplified electrical signals back to optical signals, and in a second embodiment a plurality of optical sources, one for each of the second transmission lines, convert the amplified electrical signals back to optical signals.