Enhancing Microwave-Optical Bell Pairs Generation for Quantum Transduction Using Kerr Nonlinearity

Microwave-optical quantum transduction can be achieved via quantum teleportation using microwave-optical photon Bell pairs. The standard spontaneous parametric down-conversion (SPDC) has to trade off between generation fidelity and probability due to unwanted higher-excitation pairs in the output. In this work, we propose a pulsed SPDC scheme that employs strong Kerr nonlinearity in the microwave mode. This nonlinearity causes significant detuning of higher excitations due to the anharmonicity of energy levels, and the system can be pulse-driven to produce single-photon pairs in the output. Our pulsed nonlinear approach can generate high-fidelity Bell pairs with high probability, alleviating the trade-off between fidelity and probability inherent in traditional SPDC schemes. We optimize both the pulse width and driving strength, demonstrating that our protocol outperforms the SPDC scheme in a realistic setting of finite nonlinearity and intrinsic photon loss.