The characterization of waveform measurement systems and the development of reference waveforms is now underway at the National Bureau of Standards (NBS). Efforts to upgrade the state of the art of fast waveform measurements at NBS has resulted in the development of the first photoconductive switch using GaAs in addition to a patent on the sampling of electrical signals with optical signals and vice versa. These photoconductive switches are now being applied to the development of reference waveform generators in the form of a Maxwell-Wagner two-layer capacitor in silicon stripline to complement the liquid-filled coaxial tine fitters developed previously. The silicon filters are more compact, rugged, and less expensive to fabricate. In addition, they lend themselves well to integration with photoconductive switches resulting in a reduction in connector problems and pulse excitation errors.
R. A. Lawton,
"Photoconductive Switches Used For Waveform Generation At The National Bureau Of Standards", Proc. SPIE 0439, Picosecond Optoelectronics, (28 November 1983); doi: 10.1117/12.966078; https://doi.org/10.1117/12.966078