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: 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 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 transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive user data and provide electrical signals based on the data; and a modulator operable to modulate the optical signal to provide optical subcarriers based on the electrical signals. A first one of the subcarriers carriers carries first TDMA encoded information and second TDMA encoded information, such that the first TDMA encoded information is indicative of a first portion of the data and is carried by the first one of the subcarriers during a first time slot, and the second TDMA encoded information is indicative of a second portion of the data and is carried by the first one of the subcarriers during a second time slot. The first TDMA encoded information is associated with a first node remote from the transmitter and the second TDMA encoded information is associated with a second node remote from the transmitter.

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: Optical network systems are disclosed, including a transmitter comprising a digital signal processor that receives data; circuitry that generate a plurality of electrical signals based on the data; a plurality of filters, each of which receiving a corresponding one of the plurality of electrical signals, a plurality of roll-off factors being associated with a respective one of the plurality of filters; a plurality of digital-to-analog converter circuits that receive outputs from the digital signal processor, the outputs being indicative of outputs from the plurality of filters; a laser that supplies light; and a modulator that receives the light and outputs from the digital-to-analog converter circuits, the modulator supplying a plurality of optical subcarriers based on the outputs of the digital-to-analog converter circuits, such that one of the plurality of optical subcarriers carrying information for clock recovery.

Abstract: Systems, devices, and techniques relating to optical communications are described. A described hub optical module includes an optical transceiver configured to communicate with edge optical modules of respective edge devices via an optical communication network, the edge optical modules comprising edge interfaces; and a controller coupled with the optical transceiver. The controller can be configured to provide, to a hub device, hub interfaces which are configurable to respectively correspond to different optical subcarriers transmitted from and received by the optical transceiver. The controller can advertise, to the hub device, an application select code to enable the hub device to configure an operational mode and to selectively enable each of the hub interfaces in the operational mode, store one or more associations among the hub interfaces and the edge interfaces, and configure one or more cross-connections among the hub interfaces and the optical subcarriers based on the one or more associations.

Abstract: A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive data and provide a plurality of electrical signals based on the data; and a modulator operable to modulate the optical signal to provide a plurality of optical subcarriers based on the plurality of electrical signals. One of the plurality of subcarriers carries first information indicative of a first portion of the data in a first time slot and second information indicative of a second portion of the data in a second time slot. The first information is associated with a first node remote from the transmitter and the second information is associated with a second node remote from the transmitter. A receiver as well as a system also are described.

Abstract: Optical network systems and components are disclosed including a transmitter comprising a digital signal processor receiving a plurality of independent data streams, the digital signal processor supplying outputs based on the plurality of independent data streams, the digital signal processor comprising a plurality of pulse shape filters corresponding to the plurality of independent data streams, the plurality of pulse shape filters configured to filter the independent data streams to produce a first subcarrier having a first frequency bandwidth and a second subcarrier having a second frequency bandwidth different than the first frequency bandwidth for the outputs.

Abstract: Consistent with the present disclosure, a local oscillator is provided in a receiver. The local oscillator laser a first and second mirrors and phase section and heaters are provided adjacent each portion of the laser, such that the temperature and thus the frequency of light output from the local oscillator laser may be tuned. Applying electrical power, such as a current or voltage to the phase section may result in rapid frequency tuning of light output from the local oscillator laser but over a limited frequency range. Temperature changes to the mirror sections, however, may afford frequency tuning over a wider range, but frequency tuning the mirror sections requires more time than that required to tune the phase section. Consistent with the present disclosure, a tuning method and apparatus is provided that optimizes laser tuning by selectively tuning the phase and mirror sections.

Abstract: An example apparatus includes an optical transmitter, an optical splitter, lenses, and mirrors. The optical splitter has an input and several outputs. The input of the optical splitter is optically coupled to the transmitter, such that each of the outputs of the optical splitter is operable to supply a corresponding one of a plurality of modulated optical signals, each of which includes a plurality of optical subcarriers. Each of the lenses is optically coupled to a respective one of the outputs of the optical splitter. Each of the lenses is operable to receive a corresponding one of the modulated optical signals. Each of the mirrors is optically coupled to a corresponding one of the lenses, such that each of the mirrors is operable to direct a respective one of the modulated optical signals for transmission through free space.

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 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: An example method is performed by a terrestrial control system communicatively coupled to a constellation of satellites. According to the method, instructions are transmitted to a first satellite of the constellation to transmit a plurality of first groups of optical subcarriers to a plurality of second satellites of the constellation 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 communications module of the second satellites. Further, instructions are transmitted to the second satellites to transmit a plurality of second optical subcarriers to the first satellite 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 communications module of the second satellites.

Abstract: The present invention provides a method of producing a polymer hydrogel comprising the steps of: (1) preparing an aqueous solution of a water soluble polysaccharide derivative and a polycarboxylic acid; (2) optionally agitating the solution, for example, by stirring; (3) isolating a polysaccharide derivative/polycarboxylic acid composite from the solution; and (4) heating the polysaccharide derivative/polycarboxylic acid composite at a temperature of at least about 80° C., thereby cross-linking the polysaccharide with the polycarboxylic acid. The invention also provides polymer hydrogels produced by the methods of the invention.

Abstract: Optical network systems are disclosed, including a system comprising a transmitter including a digital signal processor operable to receive a plurality of independent data streams and output a plurality of digital signals based on the plurality of independent data streams, digital-to-analog circuitry operable to supply a plurality of analog signals based on the plurality of digital signals, a laser operable to supply an optical signal, a modulator operable to receive the optical signal and supply a modulated optical signal based on the plurality of analog signals, including a plurality of optical subcarriers, each of which being associated with a corresponding one of the plurality of independent data streams, a first one of the plurality of optical subcarriers having a first spectral width and a second one of the plurality of optical subcarriers having a second spectral width different than the first spectral width; and a first and a second receiver.

Abstract: Optical network systems and components are disclosed, including a transmitter comprising a digital signal processor receiving a plurality of independent data streams, and supplying a plurality of digital subcarrier outputs, based on the plurality of independent data streams, and configurable to vary the frequency spacing between two or more of the plurality of digital subcarrier outputs; the transmitter configured to output a modulated optical signal including a plurality of optical subcarriers based on the digital subcarrier outputs wherein based on first ones of the plurality of digital outputs, the first one of the plurality of subcarriers is spectrally spaced from the second one of the plurality subcarriers by a first gap, and based on second ones of the plurality of digital outputs, the first one of the plurality of subcarriers is spectrally spaced from the second one of the plurality of subcarriers by a second gap different than the first.