Four-GHz analog data acquisition system using high-frequency guided-wave modulators.

摘要

High-frequency modulators have been used to record very fast analog voltage pulses in the Nuclear Test Program at LLNL. A system consisting of 810 nm laser diode carrier sources, 7 GHz Y-branched, balanced bridge modulators (YBBM), a kilometer of single-mode optical fiber and a streak camera recorder has been successfully fielded. The total system (minus)3db bandwidth is 4 GHz with a slow roll-off allowing the recoverable data capabilities of the system to approach 10 GHz. This system has provided us with a diagnostic tool that allows us to resolve high-frequency structure in our signals which has been calculated but never measured because of limitations in the resolution of previous measuring systems. A description of the system will be given with particular emphasis given to the YBBM modulator characteristics and performance. Fast pulse data recorded by the system will be shown and an indication of the accuracy with which the pulse can be reproduced will be provided. We expect this system to be a valuable tool that will be used regularly to study the physics of materials at extremely high temperatures and densities. Plans for upgrading the system to have a (minus)3db bandwidth of 7--8 GHz will also be discussed.