Group velocities in coplanar strip transmission lines on Si and Si/SiO2/Si substrates measured using differential electro-optic sampling

The group velocities in coplanar strip transmission lines on Si and Si/SiO2/Si substrates were compared experimentally and theoretically. To ensure the experimental accuracy, a differential electro-optic sampling system with a delay-time resolution of 30 fs and a spatial resolution of 1 mu m has been developed. Compared with the group velocity on a Si substrate, the group velocity on a Si/SiO2/Si substrate with a 2.2 mu m SiO2 layer was found to be 10% faster, which agrees well with the theoretical prediction. (C) 1996 American Institute of Physics.