A new photodiode model for circuit simulation has been developed for use in feasibility and performance studies on silicon integrated fiber‐optical detector systems. The model includes optical absorption and signal current generation from three regions: surface layer, space charge layer, and substrate. This article describes the diode model and includes simulation results for an integrated silicon fiberoptic detector system with ECL outputs, useful for optical interconnect applications such as on‐board clock distribution. Results are included for both the diode itself, showing its multipole response and the complete circuit. © 1993 John Wiley & sons, Inc.