A Novel Scheme of All-optical Analog-to-Digital Conversion Based on 4-bits Intensity-Phase Quantization

This paper presents a novel all-optical analog-to-digital conversion (ADC) scheme that integrates both intensity and phase quantization mechanisms to achieve high-resolution, high-speed signal digitization. The proposed system employs a hybrid architecture in which sampled optical pulses are modulated in parallel using cascaded intensity modulators and a phase modulation module with fixed phase shifts. By combining two cascaded intensity modulators with a 2-channel phase-shifted quantization setup, the design achieves a theoretical 4-bit resolution with significantly reduced system complexity compared to conventional approaches. System-level simulations, conducted in OptiSystem, demonstrate effective quantization of a 500 MHz analog signal using a 10 Gbit/s mode-locked pulse source. The results show strong agreement between the fitted digital output and the original analog waveform, confirming the feasibility and accuracy of the proposed architecture. The computed Effective Number of Bits (ENOB) reaches 3.91, closely aligning with the theoretical value, thereby validating the system’s performance and potential for scalable integration in photonic ADC applications.