Accurate and Scalable Simulation of Cavity-Based Networks in Modular Quantum Architectures

Cavity-mediated interconnects are a promising platform for scaling modular quantum computers by enabling highfidelity inter-chip quantum state transmission and entanglement generation. In this work, we first model the dynamics of deterministic inter-chip quantum state transfer using the Stimulated Raman Adiabatic Passage (STIRAP) protocol, analyzing fidelity loss mechanisms under experimentally achievable qubitcavity coupling and decoherence parameters. We then extend the NetSquid simulator, typically used for simulating longrange quantum communication networks, to support cavity-based communication channels for mediating inter-chip state transfer and entanglement generation. We model cavities as amplitude damping channels parameterized by physical system characteristics; cavity decay rate <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\kappa$</tex> and qubit-cavity coupling strength <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$g$</tex>, and analyze the impact of intrinsic qubit decoherence factors dictated by <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$T_{1}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$T_{2}$</tex> times. Our simulations accurately represent the system's dynamics in both strong and weak coupling regimes, and identify critical trade-offs between fidelity, latency, and noise factors. The proposed framework supports faithful modeling and scalable simulation of modular architectures, and provides insights into design optimization for practical quantum network implementations.