Traveling-wave photodetector design and measurements

A simple and accurate design method for traveling-wave photodetectors is presented and illustrated by example. Fully distributed, hybrid-coplanar, traveling-wave photodetectors are designed. Linear and nonlinear responses are measured, and linear responses are compared with design predictions. Record bandwidths of 190 GHz and record bandwidth-efficiency products of 84 GHz are measured. Behavior under high-power illumination is investigated and contrasted with lumped-element photodetectors. A phenomenological model, implying fundamental bandwidth-power limitations, is used to interpret the results.