In this article photonic implementations of two oversampled analog-to-digital converter architectures are discussed. The first, and simplest design is that of pulse-code-modulation. Simulations and an experiment are developed employing a Multiple-Quantum-Well p -i -n diode comparator. Agreement between simulation and experiment is demonstrated and the design is subsequently extended to a higher performance first order unipolar sigma-delta architecture. Results of the signal-to-noise ratio as a function of input amplitude are presented for an oversampling ratio of 100.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.