Photon-number-resolving segmented detectors based on single-photon avalanche-photodiodes

Area of Science:

• Quantum optics
• Photonics engineering

Background:

• Photon-number-resolved (PNR) detection is crucial for quantum information processing.
• Existing methods often suffer from photon loss due to detector inefficiencies and complex architectures.

Purpose of the Study:

• To investigate the feasibility and performance of PNR photodetection using single-photon avalanche photodiodes (SPADs).
• To propose and analyze a novel SPAD-based segmented waveguide detector design for improved PNR measurements.

Main Methods:

• Developing a segmented waveguide detector with SPADs side-coupled to a waveguide using a vertical directional coupler.
• Characterizing detector performance by evaluating the purities of Positive-Operator-Valued Measures (POVMs).
• Analyzing the impact of key parameters: number of SPADs, photon loss, dark counts, and electrical cross-talk.

Main Results:

• The proposed side-coupling design mitigates photon loss associated with non-ideal SPAD quantum efficiency.
• Performance evaluation through POVM purities demonstrates the effectiveness of the proposed detector architecture.
• The study quantifies the influence of dark counts and cross-talk on PNR measurement fidelity.

Conclusions:

• The side-coupled SPAD waveguide detector offers a feasible and high-performance approach for PNR photodetection.
• This design overcomes limitations of previous methods by reducing photon loss.
• The findings pave the way for more robust quantum optical measurements and applications.