A quantum communications system includes a first quantum repeater and a second quantum repeater each positioned at a repeater node and each having a first quantum memory and a second quantum memory. A first channel switch is optically coupled to the first quantum repeater and a second channel switch is optically coupled to the second quantum repeater. Further, a first sub-channel extends between and optically couples the first channel switch and the first quantum memory of the first quantum repeater, a second sub-channel extends between and optically couples the first channel switch and the first quantum memory of the second quantum repeater, a third sub-channel extends between and optically couples the second channel switch and the second quantum memory of the first quantum repeater, and a fourth sub-channel extends between and optically couples the second channel switch and the second quantum memory of the second quantum repeater.

An active mode image sensor for optical non-uniformity correction (NUC) of an active mode sensor uses a Micro-Electro-Mechanical System (MEMS) Micro-Mirror Array (MMA) having tilt, tip and piston mirror actuation to form and scan a laser spot that simultaneously performs the NUC and illuminates the scene so that the laser illumination is inversely proportional to the response of the imager at the scan position. The MEMS MMA also supports forming and scanning multiple laser spots to simultaneously interrogate the scene at the same or different wavelengths. The piston function can also be used to provide wavefront correction. The MEMS MMA may be configured to generate a plurality of fixed laser spots to perform an instantaneous NUC.

An active mode image sensor for optical non-uniformity correction (NUC) of an active mode sensor uses a Micro-Electro-Mechanical System (MEMS) Micro-Mirror Array (MMA) having tilt, tip and piston mirror actuation to form and scan a laser spot that simultaneously performs the NUC and illuminates the scene so that the laser illumination is inversely proportional to the response of the imager at the scan position. The MEMS MMA also supports forming and scanning multiple laser spots to simultaneously interrogate the scene at the same or different wavelengths. The piston function can also be used to provide wavefront correction. The MEMS MMA may be configured to generate a plurality of fixed laser spots to perform an instantaneous NUC.

Quantum repeaters and network architectures use two concatenated quantum error correction codes to increase the transmission range of quantum information. A block of data qubits collectively encode a second-layer logical qubit according to a second-layer code concatenated with a first-layer code. A first-layer quantum repeater first-layer corrects each data qubit based on a first-layer syndrome extracted therefrom. The first-layer quantum repeater transmits these first-layer-corrected qubits to a second-layer quantum repeater via a quantum communication channel. The first-layer quantum repeater also transmits the first-layer syndromes to the second-layer quantum repeater via a classical communication channel. After extracting a second-layer syndrome from the first-layer-corrected qubits, the second-layer quantum repeater uses the first-layer syndromes and second-layer syndrome to second-layer correct the first-layer-corrected qubits. The first-layer syndromes improve quantum error correction by reducing the number of sec-and-layer stabilizer measurements needed to determine which data qubits have an error.

A coherent passive optical network extender apparatus includes an extender transceiver for communication with an associated optical headend. The extender transceiver includes at least one receiving portion, at least one transmitting portion, and an extension processor. The apparatus further includes a signal adaptation unit configured to convert a downstream electrical transmission lane into a plurality of individual wavelengths. Each of the converted individual wavelengths are for transmission to one of an optical node and an end user. The apparatus further includes a plurality of transceivers, disposed within the signal adaptation unit, and configured to process and transmit the converted individual wavelengths as a bundle for retransmission to the respective end users.

A coherent passive optical network extender apparatus includes an extender transceiver for communication with an associated optical headend. The extender transceiver includes at least one receiving portion, at least one transmitting portion, and an extension processor. The apparatus further includes a signal adaptation unit configured to convert a downstream electrical transmission lane into a plurality of individual wavelengths. Each of the converted individual wavelengths are for transmission to one of an optical node and an end user. The apparatus further includes a plurality of transceivers, disposed within the signal adaptation unit, and configured to process and transmit the converted individual wavelengths as a bundle for retransmission to the respective end users.

Aspects of the disclosure provide for determining a network configuration. For instance, a system may include a controller including one or more processors. The one or more processors may be configured to receive information from each of a plurality of available nodes within a network, the plurality of available nodes including at least one aerial vehicle; determine a plurality of constraints for a future point in time, each one of the plurality of constraints including one or more minimum service requirements for a geographic area; attempt to determine a first network configuration for each of the plurality of available nodes that satisfies all of the constraints; when unable to determine the first network configuration, determine a second network configuration for the plurality of available nodes and at least one additional ground-based node that satisfies all of the constraints; and send instructions in order to affect the second network configuration.

Aspects of the disclosure provide for determining a network configuration. For instance, a system may include a controller including one or more processors. The one or more processors may be configured to receive information from each of a plurality of available nodes within a network, the plurality of available nodes including at least one aerial vehicle; determine a plurality of constraints for a future point in time, each one of the plurality of constraints including one or more minimum service requirements for a geographic area; attempt to determine a first network configuration for each of the plurality of available nodes that satisfies all of the constraints; when unable to determine the first network configuration, determine a second network configuration for the plurality of available nodes and at least one additional ground-based node that satisfies all of the constraints; and send instructions in order to affect the second network configuration.

Messages on controller area network (CAN) buses are communicated over subsea links. Messages are sent as electrical or optical signals. The present invention provides a subsea CAN BUS electronic distribution unit (EDU) for transmitting, receiving, converting, and routing electrical or optical signals sent over a subsea CAN BUS network. The CAN BUS EDU of the present invention is contained within a single housing and combines the functions of transmitting, receiving, converting, and routing electrical or optical signals sent over a subsea CAN BUS network that would typically be handled by multiple devices.

Messages on controller area network (CAN) buses are communicated over subsea links. Messages are sent as electrical or optical signals. The present invention provides a subsea CAN BUS electronic distribution unit (EDU) for transmitting, receiving, converting, and routing electrical or optical signals sent over a subsea CAN BUS network. The CAN BUS EDU of the present invention is contained within a single housing and combines the functions of transmitting, receiving, converting, and routing electrical or optical signals sent over a subsea CAN BUS network that would typically be handled by multiple devices.