Photonic Analog-to-Digital Conversion

The analog-to-digital converter (ADC) performs the crucial transformation of physical electromagnetic signals into ones and zeros that can be processed by computers. As such, it is of great importance to a vast number of electronic systems and is often a limiting component for the performance of such systems. Photonic technology is capable of overcoming many of the limitations in traditional electronic ADCs and is therefore the subject of much experimental investigation. In this article we provide a brief overview of ADCs within the context of receiver systems and of the advantages that photonic technology has to offer, as well as a discussion of recent developments in research performed at APL that promise to extend the functionality of photonic ADCs. Finally, we present the results of experiments implementing nonuniform photonic sampling techniques to unambiguously identify signals separated by many traditional Nyquist zones.