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 system comprising a hub transceiver coupled to a first network node; and a plurality of edge transceivers, each configured to be communicatively coupled to a respective second network node, and to the hub transceiver, wherein the hub transceiver is operable to transmit a first message to each of the edge transceivers, the first message comprising an indication of available optical subcarriers and availability to use multiple non-contiguous optical subcarriers; receive, a service request identifying a selected subset of the available optical subcarriers including a non-contiguous first optical subcarrier and second optical subcarrier, transmit a second message to indicate either a success or a failure, and receive, via the selected subset, data from the second network node, and wherein at least one of the edge transceivers is operable to, transmit, using the selected subset of available optical subcarriers, data from the second network node to the first network node.

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 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 system comprising a hub transceiver coupled to a first network node; and a plurality of edge transceivers, each configured to be communicatively coupled to a respective second network node, and to the hub transceiver, wherein the hub transceiver is operable to transmit a first message to each of the edge transceivers, the first message comprising an indication of available optical subcarriers and availability to use multiple non-contiguous optical subcarriers; receive, a service request identifying a selected subset of the available optical subcarriers including a non-contiguous first optical subcarrier and second optical subcarrier, transmit a second message to indicate either a success or a failure, and receive, via the selected subset, data from the second network node, and wherein at least one of the edge transceivers is operable to, transmit, using the selected subset of available optical subcarriers, data from the second network node to the first network node.

Abstract: Systems and methods are disclosed for modulating, with circuitry of a source node in a communication network, at least one optical carrier to carry data utilizing a format of a soft decision forward error correction (SD-FEC) data field of an overhead portion of a data frame; encoding, with the circuitry of the source node, first data being SD-FEC data and second data being additional data into the SD-FEC data field, the first and second data being accessible without accessing client data traffic; and transmitting, with the circuitry of the source node, the data frame including the soft decision forward error correction data field. In one implementation, the second data comprises automatic protection switching bytes.

Abstract: Systems and methods are disclosed for modulating, with circuitry of a source node in a communication network, at least one optical carrier to carry data utilizing a format of a soft decision forward error correction (SD-FEC) data field of an overhead portion of a data frame; encoding, with the circuitry of the source node, first data being SD-FEC data and second data being additional data into the SD-FEC data field, the first and second data being accessible without accessing client data traffic; and transmitting, with the circuitry of the source node, the data frame including the soft decision forward error correction data field. In one implementation, the second data comprises automatic protection switching bytes.

Abstract: Consistent with the present disclosure, a transmitter is provided that includes first and second stages of wavelength locking circuitry. The first stage includes a tunable optical filter that sweeps through the spectrum of a WDM signal at a predetermined rate. A first photodiode senses a tapped portion of the output of the tunable filter. The remaining light is fed to the second stage, which includes a second optical filter, typically having a fixed transmission characteristic. A second photodiode senses the light that passes through the second filter. By sweeping the WDM spectrum the tunable filter can be used to identify the peaks in the WDM spectrum, with each peak corresponding to an optical signal wavelength and occurring at a particular time interval during the sweep.

Abstract: Consistent with the present disclosure, clock-and-data recovery (CDR) circuitry and driver circuitry are provided on a chip that is separate from the driver circuitry, thereby reducing the amount of power consumed by the driver circuitry and simplifying system design. In one example, timing of the ERZ signals is controlled by a feedback loop that adjusts the phase of a data carrying signal relative to a clock signal, such that the phase has a desired value. Timing of the ERZ signals may thus be adjusted to minimize errors.

Abstract: A transmissive active channel element is provided in each signal channel of a monolithic multi-channel TxPIC where each channel also includes a modulated source. The active channel element functions both as a power control element for both monitoring and regulating the output channel signal level of each signal channel and as a modulator for channel wavelength tagging or labeling to provide for wavelength locking the modulated sources. The power regulating function is also employed to control the channel signal power outputs of each channel to be uniform across the channel signal array. All of these functions are carried out by a feedback loop utilizing digital signal processing.

Abstract: Consistent with the present disclosure, clock-and-data recovery (CDR) circuitry and driver circuitry are provided on a chip that is separate from the driver circuitry, thereby reducing the amount of power consumed by the driver circuitry and simplifying system design. In one example, timing of the ERZ signals is controlled by a feedback loop that adjusts the phase of a data carrying signal relative to a clock signal, such that the phase has a desired value. Timing of the ERZ signals may thus be adjusted to minimize errors.

Abstract: Consistent with the present disclosure, a transmitter is provided that includes first and second stages of wavelength locking circuitry. The first stage includes a tunable optical filter that sweeps through the spectrum of a WDM signal at a predetermined rate. A first photodiode senses a tapped portion of the output of the tunable filter. The remaining light is fed to the second stage, which includes a second optical filter, typically having a fixed transmission characteristic. A second photodiode senses the light that passes through the second filter. By sweeping the WDM spectrum the tunable filter can be used to identify the peaks in the WDM spectrum, with each peak corresponding to an optical signal wavelength and occurring at a particular time interval during the sweep.

Abstract: A transmissive active channel element is provided in each signal channel of a monolithic multi-channel TxPIC where each channel also includes a modulated source. The active channel element functions both as a power control element for both monitoring and regulating the output channel signal level of each signal channel and as a modulator for channel wavelength tagging or labeling to provide for wavelength locking the modulated sources. The power regulating function is also employed to control the channel signal power outputs of each channel to be uniform across the channel signal array. All of these functions are carried out by a feedback loop utilizing digital signal processing.

Abstract: A transmissive active channel element is provided in each signal channel of a monolithic multi-channel TxPIC where each channel also includes a modulated source. The active channel element functions both as a power control element for both monitoring and regulating the output channel signal level of each signal channel and as a modulator for channel wavelength tagging or labeling to provide for wavelength locking the modulated sources. The power regulating function is also employed to control the channel signal power outputs of each channel to be uniform across the channel signal array. All of these functions are carried out by a feedback loop utilizing digital signal processing.

Abstract: A multistage optical fiber amplifier (OFA) system is designed to be upgraded with the addition of pump power when signal capacity of an optical communication link is correspondingly increased. The system includes a gain flattening filter (GFF) that remains valid when the system is upgraded because of the system design. Also disclosed are ways to enhance the GFF as well as control the channel signal gain tilt as well as adjust the external gain uniformity to be the same for an assembly line of OFA systems.

Abstract: A multistage optical fiber amplifier (OFA) system is designed to be upgraded with the addition of pump power when signal capacity of an optical communication link is correspondingly increased. The system includes a gain flattening filter (GFF) that remains valid when the system is upgraded because of the system design. Also disclosed are ways to enhance the GFF as well as control the channel signal gain tilt as well as adjust the external gain uniformity to be the same for an assembly line of OFA systems.