Experimental demonstration of a dynamic range enhancement method for a phase-shifted PADC by using a modulo operation.

ABSTRACT

We propose what we believe to be a novel approach to enhance the dynamic range of a photonic analog-to-digital converter (PADC) without the need of additional custom-designed circuits or components. The method utilizes the unique characteristic of our previously reported multimode interference (MMI) coupler-based optical quantizer that exploits the periodicity of the optical phase to realize a modulo operation. Experiments were carried out to verify the effectiveness of the proposed method on our phase-shifted optical quantization ADC (PSOQ-ADC) chip. Experimental results show that our proposed method enhance the dynamic range from [-V π, V π] to [-2V π, 2V π] and has the potential to be further extended. Additionally, we successfully reconstructed radio frequency (RF) signals at a sampling rate of 30 Gs/s. Our work provides a promising solution for achieving a high dynamic range in on-chip PSOQ-ADC.