A Zero Added Loss Multiplexing (ZALM) Source Simulation

2025-10-29

AI Summary

This work addresses the performance optimization of zero-additional-loss multiplexing (ZALM) photon sources for quantum networks. Methodologically, we propose a modular and configurable simulation framework built upon NetSquid and the QSI controller, integrating physical models of SPDC sources, DWDM filtering, HOM interference, polarization gating, detectors, and lossy channels; it supports switching between ideal and realistic operational modes and decouples source characteristics, filter parameters, and feed-forward control to enable joint optimization. Key contributions include: (i) the first systematic characterization of the trade-off between SPDC degeneracy bandwidth and DWDM channel spacing on entanglement rate and fidelity; (ii) experimental validation that narrowing the SPDC bandwidth significantly boosts entanglement generation rate while preserving fidelity ≈ 0.8; and (iii) quantitative end-to-end analysis of e-bit rate and fidelity over a 50-km fiber link, providing both theoretical guidance and a simulation toolkit for parameter customization of ZALM sources in practical quantum network deployments.

Technology Category

• Machine Learning: Quantum Machine Learning
• Search and Optimization: Algorithm Configuration
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems
• Security and Privacy: Large-scale security measurements
• Graph Algorithms and Modeling for the Web: Foundation models and LLMs for Web-related graphs

Abstract

Zero Added Loss Multiplexing (ZALM) offers broadband, per channel heralded EPR pairs, with a rich parameter space that allows its performance to be tailored for specific applications. We present a modular ZALM simulator that demonstrates how design choices affect output rate and fidelity. Built in NetSquid with QSI controllers, it exposes 20+ tunable parameters, supports IDEAL and REALISTIC modes, and provides reusable components for Spontaneous Parametric Down Conversion (SPDC) sources, interference, Dense Wavelength Division Multiplexing (DWDM) filtering, fiber delay, active polarization gates, detectors, and lossy fiber. Physics based models capture Hong Ou Mandel (HOM) visibility, insertion loss, detector efficiency, gate errors, and attenuation. Using this tool, we map trade offs among fidelity, link distance, and entangled pairs per use, and show how SPDC bandwidth and DWDM grid spacing steer performance. Using the default configuration settings, average fidelity emains constant at 0.8 but the ebit rate decreases from 0.0175 at the source to 0.0 at 50 km; narrowing the SPDC degeneracy bandwidth increases the ebit rate significantly without affecting fidelity. The simulator enables codesign of source, filtering, and feedforward settings for specific quantum memories and integrates as a building block for end to end quantum network studies.

Problem

• Simulating ZALM source performance trade-offs between fidelity and rate
• Analyzing how SPDC bandwidth and DWDM spacing affect entanglement generation
• Enabling co-design of quantum components for specific network applications

Innovation

• Modular simulator with over 20 tunable parameters
• Physics-based models capturing HOM visibility and losses
• Enables codesign of source and filtering for memories