A preFEC BER of a selected optical link is determined. A FEC Detected Degrade (FDD) threshold, FEC Excessive Degrade (FED) threshold, and FEC limit threshold are obtained for the selected optical link. The FDD threshold is less than the FED threshold and the FED threshold is less than the FEC limit. Based on the FDD threshold, FED threshold, the FEC limit, and a determination that a postFEC BER==0, it is determined whether a link down condition of the selected optical link can be asserted or de-asserted.

If wavelength defragmentation is performed during the operation of an optical network, an instantaneous interruption of a network arises; consequently, data are lost; therefore, an optical network control method according to an exemplary aspect of the present invention includes monitoring a data volume of a client signal to be transmitted using a plurality of optical subcarriers; and performing synchronously, depending on a variation in the data volume, an optical subcarrier changing process of changing an active optical subcarrier, of the plurality of optical subcarriers, to be used for transmitting the client signal, and a remapping process of remapping the client signal onto an active optical subcarrier after having been changed.

Methods, systems, and apparatus for automatically identifying rogue Optical Network Unit (ONU) are disclosed. In one aspect, an Optical Line Terminal (OLT) determines dark power on a fiber optic link over a period of time. For a given ONU, the OLT determines an optical power of high signals and an optical power of low signals received over the fiber optic link during a timeslot assigned to the given ONU, determines a modified optical power of the high signals and a modified optical power of the low signals based on differences between the optical power of the respective signals and the dark power, determines an extinction ratio based on a ratio of the modified optical power of the high signals relative to the modified optical power of the low signals, and identifies the given ONU as a rogue ONU when the extinction ratio is outside of a specified range.

Systems and methods for determining margin in an optical network include changing powers of signals from one or more transmitters; measuring noise at one or more receivers each communicatively coupled to the one or more transmitters; and determining margin between the one or more transmitters and the one or more receivers based on the associated measured noise. The changing, the measuring, and the determining are performed in-service while the one or more transmitters are each transmitting data-bearing signals.

A network control apparatus includes a processor. The processor calculates a first OSNR corresponding to an allowable limit BER from an OSNR yield strength curve of a transmission end in a node of a transmission end. The processor acquires a reception BER of a second node of a reception end, and calculates a second OSNR corresponding to the reception BER from the OSNR yield strength curve of the transmission end. The processor calculates a first noise intensity corresponding to the allowable limit BER from the first OSNR. The processor calculates a second noise intensity corresponding to the reception BER from the second OSNR. The processor calculates a noise intensity margin, based on the first noise intensity and the second noise intensity.

Novel tools and techniques are provided for implementing network timing functionality. In some embodiments, a grand master clock(s) might receive a first timing signal from a global positioning system (“GPS”) source via a GPS antenna(s), and might send a second timing signal (which might be based at least in part on the first timing signal) to a slave clock(s), in some cases, via one or more network elements or the like. A computing system might calculate various transmission times for the second timing signal to be transmitted between the grand master clock(s) and the slave clock(s), and might calculate any time delay differences in the transmission times, might generate a third timing signal based at least in part on the calculated time delay differences (if any), and might send the third timing signal to one or more network elements, thereby providing Accurate Synchronization as a Service (“ASaaS”) functionality.

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.

A device may cause an optical signal to be transmitted via a network path. The device may receive, from a network device, a link layer discover protocol (LLDP) message. The LLDP message may include signal characteristic information regarding the optical signal. The device may adjust transmission of the optical signal based on receiving the LLDP message. The device may cause an adjusted optical signal to be transmitted via the network path based on adjusting transmission of the optical signal.

In an optical communication network that includes a plurality of interconnected network nodes, a method includes storing in each network node, and for each communication channel that traverses the node, one or more impairment margins of respective impairments that affect the communication channel. A potential communication channel that traverses a subset of the nodes in the network is identified. A quality of the potential communication channel is evaluated by processing the impairment margins stored in the nodes in the subset.

Systems and methods are disclosed for data communication by forming a hybrid that includes an electrical switching network with packet granularity of switching and store-and-forward forwarding services to network traffic and an optical switching network providing circuit granularity of switching and optical bypassing services to network traffic; applying local control of optical switching modules in the optical switching network with a network controller coupled to the electrical switching network, the optical switching network, and a loss-of-light detection module; and detecting loss-of-light in a failure point in the optical switching network and rerouting traffic to avoid the optical failure point.