Technology computer aided design (TCAD) of semiconductor devices exhibits the advantages of reduced development costs and development time. In this worka TCAD methodology has been developed for high-speed photodetectors. The calibration procedure for fixing the free parameters in the physical models employed in the simulation has been illustrated for a commercially available InGaAs/InP p-i-n photodetector. This approach has been illustrated using a specific example where the task was to optimize the absorption layer thickness of a novel photodetector structure. (c) 2005 Elsevier Ltd. All rights reserved.