Photonic Analog-To-Digital Conversion by use of Nonlinear Fabry-Perot Resonators.

Spatially parallel analog-to-digital conversion is proposed with a nonlinear Fabry-Perot resonator used as a multifunctional photonic comparator based on the pulse circulation method. The transmissive output of the photonic comparator exhibits a binary signal of either 1 or 0, depending on whether the incident intensity is greater than or less than the switching intensity corresponding to the binary weight, respectively. The photonic comparator complimentarily reflects the incident light, either with or without subtraction of the binary weight, and returns the reflected light to the next-lower digit cycle. Starting at the most significant bit, the recursive circuit successively launches the binary-coded outputs. The analog-to-digital conversion numerically demonstrates up to 6-bit resolution without noticeable errors.