Mode-discriminating photoconductor and coplanar waveguide circuit for picosecond sampling

We introduce a circuit for ultrafast measurements with coplanar waveguide t ransmission lines. The circuit contains photoconductive switches that allow tunable generation and reception of a coplanar waveguide's two propagating modes. The circuit has fewer discontinuities than other circuits with simi lar capabilities and does not require airbridges. We show how the photocond uctive switch can be biased to compensate for pump laser beam misalignment, and that a circuit composed of two chips making up a hybrid has only 4% br oader temporal resolution than a circuit integrated on a single chip. We me asured a minimum temporal resolution of 2.4 ps. (C) 1999 American Institute of Physics. [S0003-6951(99)02807-7].