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

Area of Science:

• Photonics
• Electrical Engineering
• Signal Processing

Background:

• Photonic analog-to-digital converters (PADCs) are crucial for high-speed signal processing.
• Enhancing the dynamic range of PADCs is essential for improved signal fidelity.
• Existing methods often require complex custom circuitry.

Purpose of the Study:

• To propose a novel, component-efficient method for enhancing PADC dynamic range.
• To leverage the properties of multimode interference (MMI) couplers for improved quantization.
• To demonstrate the effectiveness of the proposed technique on a phase-shifted optical quantization ADC (PSOQ-ADC) chip.

Main Methods:

• Utilized a previously reported MMI coupler-based optical quantizer.
• Exploited the phase periodicity for modulo operations.
• Implemented and tested the method on a PSOQ-ADC chip.

Main Results:

• Successfully enhanced the dynamic range of the PSOQ-ADC from [-Vπ, Vπ] to [-2Vπ, 2Vπ].
• Demonstrated potential for further dynamic range extension.
• Reconstructed radio frequency (RF) signals at a 30 Gs/s sampling rate.

Conclusions:

• The proposed method offers a novel approach to significantly boost PADC dynamic range.
• This technique avoids the need for additional custom-designed circuits or components.
• Provides a promising solution for high dynamic range on-chip PSOQ-ADCs.