Analysis of high speed and high saturation current TWPDs

The time-domain TLM method was used for rigorous analysis of TWPDs with PiN and UTC type optical waveguides. Reflection of the optical signal from the output facet of the TWPDs are taken into account as well as effects like carrier transit and life times, velocity mismatch, and RF and optical attenuation constants. For short absorption length TWPDs, the optical reflection from the output facet needs to be considered to accurately calculate the optical power generating discrete current sources. The simulated characteristics of the UTC TWPD are in very good agreement with experimental data. Dependency of the UTC TWPD's characteristics on the applied bias was investigated as well.