High Speed Data Bus Active Coupler

The author discusses the Unisys HSDB (high speed data bus) active coupler which provides a typical 13-dB power margin for HSDB systems installed in military aircraft. This high-power margin ensures reliable HSDB operation through fiber-optic component degradation. The active coupler performs optical amplification and active reshaping functions such that an incoming signal is modified only in amplitude. Signal distortion and jitter are removed by a retiming ASIC (application-specific integrated circuit). The active coupler is modular in design, and plug-in growth for a 38×38 user interface is available. The active coupler achieves better than -27 dBm sensitivity at 5×10^-11 bit error rate and outputs -8 to -12 dBm optical power. The active coupler unit weighs only 6.25 lbs and has a predicted mean time between failure of over 21000 h