GOSPEL: Ultra-Broadband Waveform Generation Using Actively Stabilized Hybrid Photonic-Electronic Circuits

GOSPEL aims at exploring, implementing, and demonstrating novel concepts for ultra-broadband photonic-electronic waveform generation that can overcome the limitations of current digital-to-analogue converters (DAC). The concept exploits spectral interleaving of optical waveforms that are modulated onto phase-locked optical carriers, thereby allowing to complement the massive spatial parallelization of digital CMOS circuits by a massive spectral parallelization of DAC interfaces. The approach lends itself to large-scale photonic-electronic integration and is scalable to waveform generation at analogue bandwidths of hundreds of GHz.

As one of the most crucial aspects, this GOSPEL scheme relies on novel stabilization concepts that allow to coherently superimpose optical tributary waveforms that have been generated in independent functional units of a large-scale photonic-electronic system and that are hence subject to phase and frequency uncertainties and to temporal phase drifts. The stabilization concept is based on digital control loops, which compensate for circuit and device-related non-idealities and allow for phase and frequency stabilization of the optical carriers using integrated optical frequency shifters.

The research at IHE consists of work on the overall system concept and modeling of photonic-DAC including calibration concepts, development of the control concept for phase drifts and frequency offsets in PICs, design of the RF-boards with high-speed interconnects and execution of system experiments for proofing the overall concept.