Equalization based inter symbol interference mitigation for time-interleaved photonic analog-to-digital converters.

Area of Science:

• Photonics
• Electrical Engineering
• Signal Processing

Background:

• Time-interleaved photonic analog-to-digital converters (TIPADCs) are crucial for high-speed signal acquisition.
• Inter-symbol interference (ISI) is a major limiting factor in TIPADC performance, causing signal distortion.
• Photodetection modeling as a pulse shaper provides a new perspective for analyzing and mitigating ISI.

Purpose of the Study:

• To develop and demonstrate an effective ISI mitigation method for TIPADCs.
• To improve the bandwidth and signal fidelity of TIPADCs.
• To validate the proposed equalization technique through experimental sampling of wideband signals.

Main Methods:

• Modeling photodetection as a pulse shaper within the TIPADC system.
• Designing and implementing a zero-forcing equalizer.
• Applying the equalizer to a single-channel TIPADC system.
• Evaluating performance using frequency response analysis and two-tone signal sampling.

Main Results:

• Suppression of periodic ripples in equivalent channel frequency responses from up to ~10 dB to ~1 dB.
• Achieved a 15 GHz bandwidth for the TIPADC after equalization.
• Reduced output power difference caused by ISI in a two-tone signal from ~10.9 dB to ~1.3 dB.

Conclusions:

• The proposed equalization method effectively mitigates ISI in TIPADCs.
• The technique enables wider bandwidth operation and improved signal quality.
• This approach offers a viable solution for enhancing the performance of high-speed photonic ADCs.