An integrated photonic circuit for color qubit preparation by third-order nonlinear interactions

TL;DR

This paper proposes an integrated photonic circuit that uses third-order nonlinear interactions to generate and manipulate color qubits with high fidelity, advancing quantum photonic technologies.

Contribution

It introduces a novel integrated circuit design utilizing difference frequency generation for high-fidelity color qubit preparation and rotation in the temporal mode basis.

Findings

Achieves near-unity fidelity in color qubit preparation.

Provides a detailed methodology for device design and operation.

Demonstrates control over qubit rotations via DFG process.

Abstract

This work presents a feasible design of an integrated photonic circuit performing as a device for single-qubit preparation and rotations through the third-order nonlinear process of difference frequency generation (DFG) and defined in the temporal mode basis. The first stage of our circuit includes the generation of heralded single photons by spontaneous four-wave mixing in a micro-ring cavity engineered for delivering a single-photon state in a unique temporal mode. The second stage comprises the implementation of DFG in a spiral waveguide with controlled dispersion properties for reaching color qubit preparation fidelity close to unity. We present the generalized rotation operator related to the DFG process, a methodology for the device design, and qubit preparation fidelity results as a function of user-accessible parameters.