Thesis Type:MSc thesis
Photonic analog to digital converters (ADC) have been the focus of much research interest in recent years, because of their potential for very high bandwidth and sampling rates. Using photonic techniques may help to surpass the limitations of traditional electronic analog to digital converters, providing unprecedented performance. A key parameter of any ADC is its conversion resolution. This works explores the technique of spatial oversampling as a means to increase resolution in photonic ADCs. Spatial oversampling is shown to be equivalent to temporal oversampling, a commonly used technique in the field of digital signal processing. The properties, benefits and requirements of spatial oversampling are derived, and the concept is demonstrated theoretically and experimentally. A photonic ADC design based on this technique is described, and an implementation as a photonic integrated circuit is presented. The design is based on electro-optic phase modulation, interferometric detection and spatial oversampling. The abilities and performance of this photonic ADC concept are demonstrated experimentally by digitizing analog signals with frequencies of up to 13GHz.