A hybrid analog-to-digital converter is described that uses photonic waveform sampling coupled with superconducting electronics for quantization and conversion to a binary format. The architecture scheme exploits extremely low clock jitter, amplitude stability, and a picosecond sampling aperture from the photonic system and magnetic flux quantization and high-speed digital logic in the superconducting system. The operational speed of the conversion is primarily limited by the maximum speed of the superconducting logic elements.