Aspects of the disclosure provide for methods and systems for feedback control of mode MUX and DEMUX. An aspect of the disclosure provides for a method associated with a mode MUX. The method includes modulating each WDM signal of a first set of WDM signals with a pilot tone of different frequency. The method further includes spatially multiplexing the first set of WDM signals to generate a multi-mode signal. The method further includes detecting the pilot tones from the multi-mode signal. The method further includes tuning the mode MUX based on the detecting. Another aspect of the disclosure provides for a method associated with a mode DEMUX. The method includes spatially demultiplexing a multi-mode signal into a set of WDM signals. The method further incudes detecting pilot tones from the set of WDM signals and tuning the mode DEMUX based on the detecting.

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.

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.

In a case where a failure occurs in a part of an optical fiber in an optical cable, when attempting to switch to a redundant configuration, the stable use of an optical transmission system is impaired, so that the wavelength band cannot be used effectively. Accordingly, the optical transmission system of the present invention includes a first optical device configured to change the transmission line of a wavelength band signal propagating through a first optical transmission line to a second optical transmission line that is the same path as the first optical transmission line, in the stage before a faulty part in the first optical transmission line, and a second optical device configured to change the transmission line of the wavelength band signal from the second optical transmission line to the first optical transmission line, in the stage after the faulty part.

An apparatus includes a first communication interface configured to be communicatively coupled, via an optical line, to a network device that is disposed in an optical network using wavelength division multiplexing (WDM). The apparatus also includes a second communication interface configured to be communicatively coupled to a router via an Ethernet connection. The apparatus also includes a signal generator operatively coupled to the first communication interface and the second communication interface. The signal generator is configured to generate an Ethernet signal representing at least one attribute of the optical line between the first communication interface and the network device. The second communication interface is configured to transmit the Ethernet signal to the router.

This disclosure describes C and L band optical communications module link extender, and related systems and methods. An example method may include receiving, by a dense wave division multiplexer (DWDM) at a headend, one or more optical data signals over a C band and an L band. The example method may also include combining the one or more optical data signals. The example method may also include outputting a second signal to a first WDM at the headend. The example method may also include separating, by the first WDM, the second signal into a C band signal and an L band signal. The example method may also include outputting the C band signal to a first amplifier at the headend and the L band signal to a second amplifier at the headend. The example method may also include amplifying, by the first amplifier, the C band signal. The example method may also include outputting an amplified C band signal to a coexistence filter. The example method may also include amplifying, by the second amplifier, the L band signal. The example method may also include outputting an amplified L band signal to the coexistence filter. The example method may also include outputting, by the coexistence filter, a third signal.

Access nodes of a large-scale network are arranged into a number of groups. The groups are arranged into a number of bands. Each distributor of a pool of distributors interconnects each access node of a selected group to at least one channel from each group of a selected band. A discipline of allocating the selected group and the selected band to a distributor ensures that each access node has: a number, approximately equal to half the number of groups, of parallel single-hop paths to each other access node of a same group; a number, approximately equal to half the number of bands, of parallel single-hop paths to each access node of a different group within a same band; and one single-hop path to each other access node of a different access band. To eliminate the need for cross connectors, geographically-spread distributors are arranged into geographically-spread constellations of collocated distributors.

A method may include determining a number of categories associated with optical network units (ONUs) in a system and assigning an allocation identifier to each of the respective categories. The method may also include transmitting the assigned allocation identifiers to the ONUs and transmitting a contention-based allocation to the ONUs, wherein the contention-based allocation includes a first one of the allocation identifiers.

A method for providing a maximum channel capacity per optical channel in an optical wavelength division multiplexing, WDM, transmission system is described. The WDM transmission system includes transceivers using multiple optical channels in a WDM channel grid to transport optical signals modulated with a modulation format with a signal symbol rate, SR, via an optical transmission link, OTL, along an optical path from a transmitting transceiver to a receiving transceiver. A channel capacity of the optical channel is maximized while a calculated channel margin, CM, is maintained above a preset minimal channel margin value.

An optical link channel auto-negotiation method and apparatus, a non-transitory computer-readable storage medium are disclosed. The optical link channel auto-negotiation method may include at least one of the following: configuring a receiving rate, determining whether a receive clock recovered from received data by a physical layer (PHY) module is locked, and in response to determining that the receive clock recovered from the received data by the PHY module is locked, determining that the receiving rate is configured correctly; configuring a first predetermined parameter in response to determining that the receiving rate is configured correctly, determining whether code block data of the PHY module is in a synchronized state, and in response to determining that the code block data of the PHY module is in a synchronized state, determining that the first predetermined parameter is configured correctly.