All-Optical Analog-to-Digital Conversion Based on Polarization-Differential Interference and Phase Modulation

A novel approach of an all-optical analog-to-digital converter is proposed and demonstrated. One single-phase modulator and a continuous-wave laser diode are used to quantize the sinusoidal tone analog signal. Software sampling measurements yielded an effective number of bits of 4.1. Benefits of the proposed setup are its simple design, high bandwidth, and stability. The scheme is primarily limited in the optical domain by the speed of the phase modulator and in electronic domain by electrical comparators and logic devices