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, a transmitter includes a laser operable to supply an optical signal, a digital signal processor operable to supply first electrical signals based on first data input to the digital signal processor and second data input to the digital signal processor, digital-to-analog conversion circuitry operable to output second electrical signals based on the first electrical signals, modulator driver circuitry is operable to output third electrical signals based on the second electrical signals, and an optical modulator operable to supply first and second modulated optical signals based on the third electrical signals. The first modulated optical signal includes a plurality of optical subcarriers carrying user data. The plurality of optical subcarriers also being amplitude modulated to carry control information.

Abstract: Comprises aggregating data received by a first number of server ports of an edge switch. The server ports operate at a first data speed. The aggregated data is distributed into a plurality of virtual lanes with each virtual lane carrying a portion of the aggregated data at a second data speed less than the first data speed.

Abstract: Systems, methods, devices, and other implementations for minimizing latency asymmetries and variations in a bi-directional link between two nodes in a communication system are described. To determine a variable latency for communication between two network nodes, a transmitting node can insert a line marker and a client marker into the data to be transmitted to the receiving node. The line marker and client marker can be inserted into the data at different portions or by different components of a transmitter. The receiving node can receive the transmitted data and extract the line marker and client marker. A delay associated with the line and client markers (Tc-TL) in the transmission device and a delay between the reception of the line and clien markers (Rc-RL) at the receiving node can be used to determine the variable latency.

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 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: Disclosed herein are methods and systems for computing a launch power for an optical node by collecting data for an optical network segment and inputting the collected data and first power spectral density values into a machine learning model which are used to compute a first non-linear interference value. A first generalized-optical signal-to-noise ratio value is computed using the computed first non-linear interference value and amplified spontaneous emission values. At least one second generalized-optical signal-to-noise ratio value is computed using at least one second non-linear interference value, computed using at least one second power spectral density values, and the amplified spontaneous emission values. A highest generalized-optical signal-to-noise ratio value is determined by comparing the first generalized-optical signal-to-noise ratio value and the at least one second generalized-optical signal-to-noise ratio value.

Abstract: Systems and methods for performing impairment compensation in point-to-multi-point communication systems are described. In a data snapshot mode, a hub node can send instructions to each communication node connected to the hub node to send a data snapshot of data being received and processed by the communication nodes at a particular time. In a trench line mode, a hub node sends instructions to each communication node to send trench line data back to the hub node. The hub node uses the data snapshot or trench line data to determine how to tune filter coefficients in the hub node to perform impairment compensation and improve performance of the communication system.

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: A network element is herein disclosed. The network element comprises an embedded device having one or more property affecting a function of the embedded device; a computing system having a processor and a memory, the memory being a non-transitory computer-readable medium storing a performance monitoring domain agent, a performance monitoring collector daemon, and a performance monitoring logger. The performance monitoring collector daemon is processor-executable code that when executed by the processor causes the processor to communicate with the embedded device and collect one or more performance information of the embedded device based on the one or more property.

Abstract: Consistent with the present disclosure, a photonic integrated circuit (PIC) is provided that has 2 N channels (N being an integer). The PIC is optically coupled to N optical fibers, such that each of N polarization multiplexed optical signals are transmitted over a respective one of the N optical fibers. In another example, each of the N optical fibers supply a respective one of N polarization multiplexed optical signals to the PIC for coherent detection and processing. A multiplexer and demultiplexer may be omitted from the PIC, such that the optical signals are not combined on the PIC. As a result, the transmitted and received optical signals incur less loss and amplified spontaneous emission (ASE) noise. In addition, optical taps may be more readily employed on the PIC to measure outputs of the lasers, such as widely tunable lasers (WTLs), without crossing waveguides.

Abstract: An optical transceiver with a built-in heat transfer structure is described. The heat transfer structure can connect one or more circuit regions of the optical transceiver to a heat sink while bypassing circuit regions that may impede the transfer of heat from the one or more circuit regions. The heat transfer structure may directly contact the one or more circuit regions, and the heat sink and may include an opening to avoid contact with the circuit regions to be bypassed.

Abstract: Methods and systems for stitching real-time and historical data are disclosed herein. The data may be gathered from a line card and represent metrics of hardware or software elements of the line card. The historical data may be transferred and stored in an archive of a control card of a network element and the real-time data may be accessed by a proxy host of the control card substantially in real-time. A network administration device may access the historical data on the file collector and/or the real-time data from the proxy host of the control card and convert them to a time series database format and store the converted data in a time series database. A user may access a portion of the converted real-time and/or historical data using a graphical user interface, the accessed portion representing data gathered during a period of time selected by the user.

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: Consistent with the present disclosure, an encoder circuit is provided at a transmit side of an optical fiber link that maps an input sequence of bits of fixed length k a sequence of symbols of a codeword of length n, such that the symbols of the codeword define a predetermined transmission probability distribution. Preferably, each symbol of the codeword is generated during a corresponding clock cycle, such that after n clock cycles, a complete codeword corresponding to the input bit sequence is output. On a receive end of the link, a decoder is provided that outputs the k-bit sequence every n clock cycles. Accordingly, buffers need not be provided at the output of the encoder and the input of the decoder, such that processing of the input sequence, codewords, and output sequence may be achieved efficiently without large buffers and complicated circuitry. Moreover, the input sequence, with any binary alphabet may be matched to a desired output distribution with any arbitrary alphabet.

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, an encoder circuit is provided at a transmit side of an optical fiber link that maps an input sequence of bits of fixed length k to a sequence of symbols of a codeword of length n, such that the symbols of the codeword define a predetermined transmission probability distribution. In one example, each subgroup of bits of the k input bit sequence is provided to a respective look-up table, whereby the sub-group of bits constitutes an address of a particular memory location in the corresponding look-up table. Based on the address, the contents at the particular memory location addressed by each subgroup of bits are output as a corresponding portion of a codeword. Each such codeword portion is provided to a further memory or buffer, such that the entire codeword is assembled in the buffer and output to forward error correction (FEC) circuitry.

Abstract: Systems, methods, and devices for encoding and decoding a packet buffer for data exchange over a communications network, including parsing a data container definition file to determine a packet format; generating a code file based on the data container definition file; inserting the code file into a source tree of an application; compiling the source tree to generate an executable file; and executing the executable on a computing device in communication with the communications network, wherein the executable file encodes and decodes the packet buffer for data exchange over the communications network.

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: Methods, systems, and apparatus for subcarrier modulation with radio frequency inphase-quadrature (IQ) modulators. A system includes a plurality of IQ modulators, each configured to receive an input electrical signal comprising an inphase signal and a quadrature signal, and each configured to modulate the inphase signal and quadrature signal based on one of a plurality of local oscillator signals to output a multiplexed signal. Each of the plurality of local oscillator signals is supplied by a respective one of a plurality of local oscillator circuits. A modulator circuit is configured to modulate a carrier optical signal from a laser having a frequency ?c based on the multiplexed signal to generate a modulated optical signal centered at frequency ?c and comprising a plurality of subcarriers. A center frequency of each of the plurality of subcarriers is offset from ?c by a frequency of said one of the plurality of local oscillator signals.

Abstract: A regen node is described. The regen node includes a coherent receiver, a control module and a coherent transmitter. The coherent receiver has circuitry to convert a first optical signal received from an upstream node in an optical layer of an optical network to a first digital data stream in a digital layer having a first FEC frame and a data traffic. The control module extracts a first fault signal from the first FEC frame; generates a second fault signal based at least in part on the first fault signal; and encodes the second fault signal within a second FEC frame with the data traffic into a second digital data stream on the digital layer. The coherent transmitter has circuitry to convert the second digital data stream into a second optical signal on the optical layer and to transmit the second optical signal to a downstream node.