Abstract: Systems and methods for generating an entangled pair of bichromatic photons are described. The system includes an atomic vapor cell containing atoms of an atomic species located within beam paths of a first and second laser beam. The first and In second laser beams are tuned to first and second wavelengths that are resonant with first and second atomic transitions of the atomic species such that the first and second laser beams cause a four-wave mixing process within the atomic vapor cell. As a result of the four-wave mixing process, entangled photon pairs having a third and fourth wavelength are generated and output from the atomic vapor cell. The first and second wavelengths may be selected to create electromagnetically-induced transparency (BIT) within the atomic vapor cell, the BIT creating a transparent medium within the atomic vapor cell at the third wavelength, improving spectral brightness and/or photon linewidths.

Abstract: A quantum memory device and methods for storage and retrieval of a qubit from the quantum memory device are described. The quantum memory device includes a first optical component to convert an input qubit encoded in an arbitrary polarization state of a photon into a spatial qubit propagating in a pair of parallel optical rails, an atomic vapor memory to store the spatial qubit in an atomic vapor, and a second optical component to combine the spatial qubit, when retrieved from the atomic vapor memory, into an output qubit encoded in an arbitrary polarization state of a photon.

Abstract: Quantum network devices, systems, and methods are provided to enable long-distance transmission of quantum bits (qubits) for applications such as Quantum Key Distribution (QKD), entanglement distribution, and other quantum communication applications. Such systems and methods provide for separately storing first, second, third, and fourth photons, wherein the first and second photons and the third and fourth photons are respective first and second entangled photon pairs, triggering a synchronized retrieval of the stored first, second, third, and fourth photons such that the first photon is propagated to a first node, the second and third photons are propagated to a second node, and the fourth photon is propagated to a third node, and creating a new entangled pair comprising the first and fourth photons at the first and third nodes to transmit quantum information.

Abstract: Systems and methods for performing polarization compensation in optical fiber-based quantum telecommunications systems are provided. The system includes a polarization modulator optically coupled to a photon source by an optical fiber and at least one controller coupled to the polarization modulator. The at least one controller is configured to determine, using a machine learning model and/or a lookup table, a feedback parameter based on one or more measurements of a polarization of probe photons at a location along the optical fiber, the probe photons being generated by the photon source; and using the feedback parameter, to change a setting of the polarization modulator to change a polarization of quantum data photons propagating in the optical fiber subsequent to the probe photons.

Abstract: Quantum network devices, systems, and methods are provided to enable long-distance transmission of quantum bits (qubits) for applications such as Quantum Key Distribution (QKD), entanglement distribution, and other quantum communication applications. Such systems and methods provide for separately storing first, second, third, and fourth photons, wherein the first and second photons and the third and fourth photons are respective first and second entangled photon pairs, triggering a synchronized retrieval of the stored first, second, third, and fourth photons such that the first photon is propagated to a first node, the second and third photons are propagated to a second node, and the fourth photon is propagated to a third node, and creating a new entangled pair comprising the first and fourth photons at the first and third nodes to transmit quantum information.

Abstract: An optical system including an optical cavity and a method of tuning an optical cavity using a machine learning model is provided. The method includes determining a tuning parameter of the optical cavity by: analyzing, using a convolutional neural network (CNN) model, a measurement signal obtained from the optical cavity to determine a degree of misalignment of the optical cavity; and determining, using a reinforcement learning (RL) model, the tuning parameter based on the degree of misalignment of the optical cavity.

Abstract: Devices, systems, and methods for ambient-temperature quantum information buffering, storage, and communication are provided enabling receiving a quantum communication (for example, photons holding quantum information, e.g., qubits), storing the qubits in a room-temperature scalable quantum memory device, selectively retrieving the qubits, performing filtering, and extracting the quantum communication with a controllable delay.

Abstract: Quantum network devices, systems, and methods are provided to enable long-distance transmission of quantum bits (qubits) for applications such as Quantum Key Distribution (QKD), entanglement distribution, and other quantum communication applications. Such systems and methods provide for separately storing first, second, third, and fourth photons, wherein the first and second photons and the third and fourth photons are respective first and second entangled photon pairs, triggering a synchronized retrieval of the stored first, second, third, and fourth photons such that the first photon is propagated to a first node, the second and third photons are propagated to a second node, and the fourth photon is propagated to a third node, and creating a new entangled pair comprising the first and fourth photons at the first and third nodes to transmit quantum information.

Abstract: Devices, systems, and methods for ambient-temperature quantum information buffering, storage, and communication are provided enabling receiving a quantum communication (for example, photons holding quantum information, e.g., qubits), storing the qubits in a room-temperature scalable quantum memory device, selectively retrieving the qubits, performing filtering, and extracting the quantum communication with a controllable delay.