A photonic analog-to-digital converter is provided that includes a tunable light source, an optical sampling clock source, an optical splitter and a plurality of optical signal processing channels. The tunable light source produces an optical signal at a variable wavelength corresponding to analog levels of an electrical input signal. The optical sampling clock source produces an optical sampling clock signal that defines a sequence of sampling periods. The optical splitter is operably coupled to the tunable light source. The optical splitter splits the optical signal produced by the tunable light source for supply to the plurality of optical signal processing channels. Each one of the optical signal processing channels includes a photonic filter and corresponding optoelectronic thyristor comparator that is operably coupled to the optical sampling clock source. The optoelectronic thyristor comparator operates as a discriminator that generates a digital electrical signal representing whether the optical signal produced by the tunable light source has a wavelength that lies within a predetermined wavelength quantization level during the sampling periods defined by the optical sampling clock source. The photonic analog-to-digital converter further includes circuitry that generates a digital word corresponding to the digital electrical signals generated by the optoelectronic thyristor comparators of the plurality of optical signal processing channels.