If you're interested in finding out more, I've included the slides from a recent talk at LEOS '99 in pdf format. Also, feel free to email me , or check out the pages of other people working on optical interconnects in the Miller group. Second, the low jitter output from the laser provides a low jitter signal for clock distribution and, provided the data are also transmitted optically, enables easy synchronization between clock and data. The optical devices are GaAs multiple quantum well diodes, flip-chip bonded by Lucent Technologies. The diodes serve as both modulators and detectors, have a pitch of 62.5 microns, and are placed in lx20 arrays with 125 micron spacing.
Channels are differential, an architecture allowing better system performance with low voltages.
These beams are reflected in free space from the modulators on the transmitter chip to the detectors on the receiver chip. The transmitter chip is driven with electrical signals from an HP 8133A pulse generator, frequency locked to the laser pulse rate. This final modulated beam is analyzed using a Tektronix P6701 optical detector with a signal bandwidth of 700 MHz, and the output is recorded using an HP 54750A digital oscilloscope. In both cases, a cw laser is used to read the channel state at the receiver chip. The receiver optical output circuitry is neither clocked nor latched, so the receiver output can be seen to relax to the off state with a characteristic time constant.