Abstract: Consistent with the present disclosure, the above-described subcarrier noise, which may be characterized as a linear filtering effect, may be reduced or eliminated by providing a first multiple-input multiple output (MIMO) circuits at the transmit end of an optical link and providing a second MIMO circuit at the receive end of the optical link. The first MIMO may include a first plurality of filters, each of which may include a finite-impulse response (FIR) filter having variable coefficients or tap weights that may be changed or adapted to minimize subcarrier noise associated with the modulator, as well as D/A and analog circuitry, at the transmit end of the optical link. In addition, the second MIMO may include a second plurality of filters, each of which may also include an FIR filter having variable coefficients or tap weights that may be changed or adapted to minimized subcarrier noise associated with the optical hybrids, as well as A/D and analog circuitry, at the receive end of the optical link.

Abstract: Consistent the present disclosure, a network or system is provided in which a hub or primary node may communication with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity that may be greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed that receive data carrying optical signals from and supply data carrying optical signals to the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, and optical add/drop multiplexer, for example. Consistent with an aspect of the present disclosure, optical subcarriers may be transmitted over such connections. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.

Abstract: An example system includes a first network device having first circuitry. The first network device is configured to perform operations including receiving data to be transmitted to a second network device over an optical communications network, and transmitting first information and second information to the second device. The first information is indicative of the data, and is transmitted using a first communications link of the optical communications network and using a first subset of optical subcarriers. The second information is indicative of the data, and is transmitted using a second communications link of the optical communications network and using a second subset of optical subcarriers. The first subset of optical subcarriers is different from the second subset of optical subcarriers.

Abstract: An example system includes a first network device having first circuitry. The first network device is configured to perform operations including receiving data to be transmitted to a second network device over an optical communications network, and transmitting first information and second information to the second device. The first information is indicative of the data, and is transmitted using a first communications link of the optical communications network and using a first subset of optical subcarriers. The second information is indicative of the data, and is transmitted using a second communications link of the optical communications network and using a second subset of optical subcarriers. The first subset of optical subcarriers is different from the second subset of optical subcarriers.

Abstract: A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.

Abstract: This disclosure describes digitally generating sub-carriers (SCs) to provide isolation and dynamic allocation of bandwidth between uplink and downlink traffic between transceivers that are communicatively coupled via a bidirectional link including one or more segments of optical fiber. Separate uplink and downlink communication channels may be created using digitally generated SCs and using the same transmitter laser. In some implementations, one or more of the nodes include a transceiver having at least one laser and one digital signal processing (DSP) operable for digitally generating at least two SCs and detecting at least two SCs. The transceiver can transmit selected SCs, and can receive other SCs. Accordingly, the transceiver can facilitate bidirectional communication, for example, over a single optical fiber link. In some instances, techniques can facilitate dynamic bandwidth assignment by facilitating adding or blocking of optical subcarriers from transmission in an uplink or downlink direction.

Abstract: A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.

Abstract: An example system includes a hub transceiver and a plurality of edge transceivers. The hub transceiver is operable to determine a plurality of optical subcarriers available for assignment by the hub transceiver to the plurality of the edge transceivers for use in communicating over an optical communications network, and assign, to each of the edge transceivers, a respective subset of the optical subcarriers. Each of the subsets of the optical subcarriers includes a respective data optical subcarrier for transmitting data over the optical communications network. At least one of the subsets of the optical subcarriers includes one or more respective idle optical subcarriers. The hub t transceiver is also operable to transmit to each of the edge transceivers, an indication of the respective subset of the optical subcarriers assigned to the edge transceiver.

Abstract: Joint estimation of the framer index and the frequency offset in an optical communication system are described among various other features. A transmitter can transmit data frames using pilot and framer symbols. A receiver can estimate the framer index and frequency offset using the pilot and framer symbols, and identify the beginning of a header portion of a data frame. By identifying the beginning of the header portion of a data frame, the receiver can then process data received from the transmitter in a manner synchronous to the manner in which the data was transmitted by the transmitter.

Abstract: An example apparatus includes a first communications module having a first transceiver. The first communications module is operable to transmit, using the first transceiver, a plurality of first groups of optical subcarriers to a plurality of second communications modules via free-space optical communication. The first groups of optical subcarriers carry first data, and each of the first groups of optical subcarriers is associated, respectively, with a different one of the second communications modules. The first communications module is also operable to receive, using the first transceiver, plurality of second groups of optical subcarriers from the second communications modules via free-space optical communication. The second groups of optical subcarriers carry second data and each of the second groups of optical subcarriers is associated, respectively, with a different one of the second communications modules.

Abstract: Optical network systems are disclosed, including systems having transmitters with a digital signal processor comprising forward error correction circuitry that provides encoded first electrical signals based on input data; and power adjusting circuitry that receives second electrical signals indicative of the first electrical signals, the power adjusting circuitry supplying third electrical signals, wherein each of the third electrical signals is indicative of an optical power level of a corresponding to one of a plurality of optical subcarriers output from an optical transmitter.

Abstract: An example system includes a hub transceiver, a plurality of edge transceivers, and a control module. The control module is operable to receive, from one or more of the edge transceivers or the hub transceiver, telemetry data regarding at least one of a transmission or a receipt of data over the optical communications network, and determine, based on the telemetry data, performance characteristics regarding the optical communications network. Further, the control module is operable to transmit, based on the performance characteristics, a command to one or more of the edge transceivers or the hub transceiver to modify an operation with respect to the optical communications network.

Abstract: An optical network component and method are herein described. The system and method include determining a first power of an optical modulator using a first photodetector and a second power of the transmitter using a second photodetector, determining a contrast ratio based on the first power and the second power, and determining a modulation loss based on the contrast ratio.

Abstract: In an example method, network traffic transmitted between a plurality of network nodes via a communications network is monitored. Subsets of the network traffic are ranked according to one or more ranking criteria. A mesh network is deployed between the plurality of network nodes based on the ranking of the subsets of the network traffic. The mesh network includes a plurality of network links, where each network link communicatively couples a respective network node from among the plurality of network nodes to another respective network node from among the plurality of network nodes.

Abstract: A transmitter block, comprising an optical source, a modulator, a transmission circuit and a control circuit. The optical source has a laser providing an optical signal. The modulator is configured to encode data into the optical signal using an m-quadrature amplitude modulation format. The transmission circuit has circuitry to receive data to be encoded into the optical signal. The transmission circuit has at least one drive circuit supplying driver signals to the modulator to cause the modulator to encode data into the optical signal using the m-quadrature amplitude modulation format. The control circuit supplies control signals to the transmission circuit to cause the transmission circuit to change the m-quadrature amplitude modulation format from a first m-quadrature amplitude modulation format to a second m-quadrature amplitude modulation format based upon predicted degradation of a link to receive modulated data from the modulator.

Abstract: A network or system in which a hub or primary node may communicate with a plurality of leaf or secondary nodes. The hub node may operate or have a capacity greater than that of the leaf nodes. Accordingly, relatively inexpensive leaf nodes may be deployed to receive data carrying optical signals from, and supply data carrying optical signals to, the hub node. One or more connections may couple each leaf node to the hub node, whereby each connection may include one or more spans or segments of optical fibers, optical amplifiers, optical splitters/combiners, and optical add/drop multiplexer, for example. Optical subcarriers may be transmitted over such connections, each carrying a data stream. The subcarriers may be generated by a combination of a laser and a modulator, such that multiple lasers and modulators are not required, and costs may be reduced.

Abstract: An example system includes a transceiver and a microcontroller. The microcontroller is configured to receive, from first and second network interfaces of the transceiver, a plurality of messages from a hub node and the leaf nodes. Each of the messages corresponds to a respective one of the ingress or egress data flows. The microcontroller is also configured generate a resource assignment map based on the messages. The resource assignment map includes pairings between a respective one of the ingress data flows and a respective one of the egress data flows, and, for each of the pairings, an indication of a respective network resource assigned to exchange the egress data flow of that pairing with a respective one of the leaf nodes. The microcontroller is also configured to generate a command to cause the transceiver to transmit the egress data flows in accordance with the resource assignment map.

Abstract: An example system includes an optical gateway, plurality of hub transceivers, and a plurality of edge transceivers. The optical gateway is operable to receive a plurality of signals from an optical communications network at a plurality of ports of the optical gateway, where each port of the optical gateway comprises one or more respective photodiodes. Further, the optical gateway is operable to determine, for each port, a respective link of the optical communications network communicatively coupling the port with at least one hub transceiver of the plurality of hub transceivers or with at least one edge transceiver of the plurality of edge transceivers, and an identity of the at least one hub transceiver or the at least one edge transceiver.

Abstract: An example system includes a network switch and a plurality of server computers communicatively coupled to the first network switch. The network switch includes a first transceiver configured to transmit data according to a first maximum throughput, and each server computer includes a respective second transceiver configured to transmit data according to a second maximum throughput that is less than the first maximum throughput. The network switch is configured to transmit, using the first transceiver according to the first maximum throughput, first data including a plurality of optical subcarriers to each of the server computers. Each of the server computers is configured to receive, using a respective one of the second transceivers, the first data from the network switch, and extract, from the first data, a respective portion of the first data addressed to the server computer.

Abstract: Consistent with the present disclosure, a networking system is provided whereby flexible optical bandwidth or capacity between a primary or hub node and secondary or leaf nodes is realized to reduce overall cost and power consumption. Packets are multi-cast from a high speed transceiver in the hub node (or optical line terminal (OLT) to one or more sets of low speed transceivers in the leaf node (optical network terminal (ONT) or optical network unit (ONU)) allowing sets of low speed transceivers to pool together and share the total bandwidth allocated and received from the high speed transceiver. In one example, the hub node outputs a plurality of optical subcarriers, each of which being designated for one or more leaf nodes. Accordingly, the intended leaf node output data associated with its designated optical subcarrier or subcarriers as the case may be and supplies the data to a transceiver at the client premises.