Oversampled Photonic Analog-to-Digital Conversion

Abstract

Oversampled A/D converters provide a means of trading bandwidth for improved amplitude resolution. In this chapter, we present a photonic implementation of an oversampling A/D converter based on MQW modulators. We begin by reviewing the functionality necessary to implement an error diffusion-type oversampling modulator. In Sect. 6.2 we present both interferometric and noninterferometric approaches to the implementation of the optical oversampled modulator and discuss advantages and disadvantages of each. We then present options for both electronic postprocessing and optical postprocessing in Sect. 6.3 and then summarize the findings for the photonic-based oversampling A/D converter. In Sect. 6.4 nonidealities such as arithmetic errors, non-white quantization noise, and stage-to-stage mismatch errors are evaluated both analytically and using a mixed-signal simulation program. Finally, in Sect. 6.5 the results of an experimental demonstration of a first-order photonic error diffusion modulator are presented.