Abstract: Consistent with the present disclosure, a DDR photodiode is provided on a substrate adjacent to a passive waveguide. In order to efficiently capture light output from the waveguide, the photodiode is coupled to the waveguide with a butt-joint. As a result, the photodiode and the waveguide abut one another such that the dominant mode of light propagating in the waveguide parallel to the substrate is supplied directly to a side of the absorber layer of the photodiode without, in one example, evanescent coupling, nor is a resonant coupler required to supply light to the photodiode. Thus, light is absorbed more efficiently in the photodiode such that the photodiode may have a shorter length. In addition, since substantially all light is input to the photodiode, nearly complete absorption and nearly ideal quantum efficiency can be achieved in a relatively short length. Further, the improved linearity associated with DDR photodiodes is preserved with the exemplary butt joint configurations disclosed herein.

Abstract: An optical network component, system, and method are herein described. The system and method include introducing an AM tone and data to an optical modulator generating a modulated optical signal, measuring an amplitude response of the AM tone within the modulated optical signal, calculating a frequency response based on the amplitude response, and calibrating the optical modulator with the frequency response.

Abstract: Consistent with the present disclosure, a DDR photodiode is provided on a substrate adjacent to a passive waveguide. In order to efficiently capture light output from the waveguide, the photodiode is coupled to the waveguide with a butt-joint. As a result, the photodiode and the waveguide abut one another such that the dominant mode of light propagating in the waveguide parallel to the substrate is supplied directly to a side of the absorber layer of the photodiode without, in one example, evanescent coupling, nor is a resonant coupler required to supply light to the photodiode. Thus, light is absorbed more efficiently in the photodiode such that the photodiode may have a shorter length. In addition, since substantially all light is input to the photodiode, nearly complete absorption and nearly ideal quantum efficiency can be achieved in a relatively short length. Further, the improved linearity associated with DDR photodiodes is preserved with the exemplary butt joint configurations disclosed herein.

Abstract: Consistent with the present disclosure, a DDR photodiode is provided on a substrate adjacent to a passive waveguide. In order to efficiently capture light output from the waveguide, the photodiode is coupled to the waveguide with a butt-joint. As a result, the photodiode and the waveguide abut one another such that the dominant mode of light propagating in the waveguide parallel to the substrate is supplied directly to a side of the absorber layer of the photodiode without, in one example, evanescent coupling, nor is a resonant coupler required to supply light to the photodiode. Thus, light is absorbed more efficiently in the photodiode such that the photodiode may have a shorter length. In addition, since substantially all light is input to the photodiode, nearly complete absorption and nearly ideal quantum efficiency can be achieved in a relatively short length. Further, the improved linearity associated with DDR photodiodes is preserved with the exemplary butt joint configurations disclosed herein.

Abstract: Consistent with a further aspect of the present disclosure, previously encoded data is stored in a memory, and an encoder accesses both input data and previously encoded data to generate new encoded data or a new codeword. Each codeword is stored in a row of the memory, and with each newly generated codeword, each previously stored code word is shifted to an adjacent row of the memory. In one example, the memory is delineated as a plurality of blocks including rows and columns of bits. When generating a new code word, randomly selected columns of bits in the memory are read from randomly selected blocks of the memory and supplied to the encoder. In this manner the number of times the memory is access is reduced and power consumption is reduced.

Abstract: Optical network systems and components 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 DACs 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 DACs, and supplies a plurality of optical subcarriers based on the outputs, such that one of the optical subcarriers has a frequency bandwidth that is wider than remaining ones of the optical subcarriers, said one of the optical subcarriers carrying information for clock recovery.

Abstract: Consistent with the present disclosure, a DDR photodiode is provided on a substrate adjacent to a passive waveguide. In order to efficiently capture light output from the waveguide, the photodiode is coupled to the waveguide with a butt-joint. As a result, the photodiode and the waveguide abut one another such that the dominant mode of light propagating in the waveguide parallel to the substrate is supplied directly to a side of the absorber layer of the photodiode without, in one example, evanescent coupling, nor is a resonant coupler required to supply light to the photodiode. Thus, light is absorbed more efficiently in the photodiode such that the photodiode may have a shorter length. In addition, since substantially all light is input to the photodiode, nearly complete absorption and nearly ideal quantum efficiency can be achieved in a relatively short length. Further, the improved linearity associated with DDR photodiodes is preserved with the exemplary butt joint configurations disclosed herein.

Abstract: Consistent with the present disclosure, a transmitter is provided in a hub node of a point-to-multi-point optical communication system. The transmitter supplies a plurality or group of optical subcarriers, each subgroup of the group of optical subcarriers in, one example, is associated with a respective leaf node. Since the leaf nodes may be located at different distances from the hub node, the modulation of each optical subcarrier subgroup is optimized for the distance and impairments associated with the optical path over which the subcarrier subgroup is transmitted to its designated leaf. Namely, probabilistic shaping is employed, in one example, to adjust the modulation so that a maximum spectral efficiency is supported for a given SNR associated with the hub-leaf link.

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 optical transceiver having a locking assembly that prevents undesirable movement of the optical transceiver when engaged with another device is described. The locking assembly includes a slide with a projection, lift, and weighted stops. In a first configuration, the slide and weighted stops can sustain contact between a thermal interface material of the optical transceiver and the other device while locking the optical transceiver to prevent movement. In a second configuration mode, the locking assembly disengages the thermal interface material from the other device and unlocks the weighted stops to permit disconnection from the other device.

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: 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 synchronize, with less error, the data transmitted by the transmitter and the data it received. To further improve the framer index estimation, a lock indicator signal can be generated to signal to other receiver components that the estimated framer indices are reliable. The receiver can determine frequency offset and additional framer index estimations with increased reliability when performed after the lock indicator signal is generated.

Abstract: Implementations for remotely managing an optical transceiver connected to a network device and optical network is described. A user can use a network device controller and optical transceiver controller in a remote server to communicate with the service agent in the network device and the optical transceiver to configure communications with the optical network through the optical transceiver. The service agent and its controller in the server can perform virtualized transport functions and the network device controller and the network device can, in some instances, implement layer 2/3 demarc.

Abstract: Techniques are described for implementing an out-of-band communication channel used to exchange control channel information in sub-carrier-based optical communication systems. In an example implementation, an optical communication system includes a primary transceiver, a component, and secondary transceivers. The primary transceiver is operable to supply first optical subcarriers to an optical communication path, the first optical subcarriers being amplitude modulated at a first frequency to carry first control information and amplitude modulated at a second frequency to carry second control information. The component is operable to be coupled to the optical communication path and includes circuitry operable to detect the first control information. The secondary transceivers are coupled to a terminal end of the optical communication path. At least one of the secondary transceivers is operable to detect the second control information and block the first control information.

Abstract: An example system includes a hub transceiver and a plurality of edge transceivers. The hub transceiver is operable to transmit, over a first communications channel, a first message to each of the edge transceivers concurrently, including an indication of available network resources on an optical communications network. Each of the edge transceiver is operable to transmit, transmit, over a second communications channel, a respective second message to the hub transceiver including an indication of a respective subset of the available network resources selected by the edge transceiver for use in communicating over the optical communications network. Further, the edge transceiver is operable to receive, from the hub transceiver, a third message acknowledging receipt of a selection and a fourth message confirming an assignment of the selected subset of the available network resources to the edge transceiver.

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: 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: 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 system comprising a hub transceiver and edge transceivers is described. The hub transceiver is coupled to a first network node via an optical communications network. Each of the edge transceivers is coupled to a respective second network node, and to the hub transceiver. The hub transceiver is operable to form one or more logical partition of optical subcarriers in an optical signal based on connection types. Each logical partition has a first partition boundary, a second partition boundary and a plurality of subcarriers logically between the first partition boundary and the second partition boundary. Each partition boundary is assigned a particular connection type. The hub transceiver assigns a subset of available optical subcarriers of the plurality of subcarriers where each assignment includes a number of optical subcarriers based on the connection type in the service request, and a subcarrier location within the one or more logical partition.

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.