Dynamic error-quantizer tuning systems and methods prevent misconvergence to local minima by using a dynamic quantizer circuit that controls reference voltages of three or more comparators that are independently adjusted to modify the transfer function of the dynamic quantizer circuit. A weighted sum of the comparator outputs is subtracted from the input to form an error signal in a control loop. The ratio of the reference voltages is chosen to reduce or eliminate local minima during a convergence of the control loop and is set to values that minimize a mean squared error signal with respect to discrete modulation states of the input after the convergence of the control loop is complete.

Systems, methods, and storage media for detecting a security intrusion of a network device are disclosed. Exemplary implementations may include a method involving, in the network device including a processor, monitor a light signal associated with a security enabled port of the network device; and in response to detecting a change in the light signal, initiate a security alert.

Systems, methods, and storage media for detecting a security intrusion of a network device are disclosed. Exemplary implementations may include a method involving, in the network device including a processor, monitor a light signal associated with a security enabled port of the network device; and in response to detecting a change in the light signal, initiate a security alert.

Systems, methods, and storage media for detecting a security intrusion of a network device are disclosed. Exemplary implementations may include a method involving, in the network device including a processor, monitor a light signal associated with a security enabled port of the network device; and in response to detecting a change in the light signal, initiate a security alert.

Systems, methods, and storage media for detecting a security intrusion of a network device are disclosed. Exemplary implementations may include a method involving, in the network device including a processor, monitor a light signal associated with a security enabled port of the network device; and in response to detecting a change in the light signal, initiate a security alert.

A method for phase correction, the method may include generating in parallel and by a set of phase error detectors, a set of phase error detection results (PEDRs) related to a set of blocks of digital samples, the digital samples are frequency corrected and represent optical signals conveyed over a coherent optical communication link; wherein the PEDs introduce PED noise that is indifferent to phase errors of the set of the blocks of digital samples; sending, in a sequential manner, the set of PEDRs, to a loop that comprises a loop filter; generating, by the loop, phase difference results, wherein each phase difference result is indicative of a phase difference between a certain PEDR of the PEDRs and a loop filtered PEDR generated by filtering a PEDR that precedes the certain PEDR; and processing, by a phase correction unit, the digital samples and the phase different results, to provide phase corrected digital samples.

A method for phase correction, the method may include generating in parallel and by a set of phase error detectors, a set of phase error detection results (PEDRs) related to a set of blocks of digital samples, the digital samples are frequency corrected and represent optical signals conveyed over a coherent optical communication link; wherein the PEDs introduce PED noise that is indifferent to phase errors of the set of the blocks of digital samples; sending, in a sequential manner, the set of PEDRs, to a loop that comprises a loop filter; generating, by the loop, phase difference results, wherein each phase difference result is indicative of a phase difference between a certain PEDR of the PEDRs and a loop filtered PEDR generated by filtering a PEDR that precedes the certain PEDR; and processing, by a phase correction unit, the digital samples and the phase different results, to provide phase corrected digital samples.

In an optical network having a terrestrial terminal and an open cable interface (OCI) connecting a submarine cable to a terrestrial cable, the OCI may include a filter positioned on an optical path between the terrestrial cable and the submarine cable and configured to pass first communication signals of a first frequency band, and filter out secondary signals of a second frequency band that does not overlap with the first frequency band. The secondary signals may be looped back to the terrestrial terminal. The terrestrial terminal may detect the looped back secondary signals, and in response, determine the presence of the OCI and that the supervisory signals were rerouted by the OCI.

In an optical network having a terrestrial terminal and an open cable interface (OCI) connecting a submarine cable to a terrestrial cable, the OCI may include a filter positioned on an optical path between the terrestrial cable and the submarine cable and configured to pass first communication signals of a first frequency band, and filter out secondary signals of a second frequency band that does not overlap with the first frequency band. The secondary signals may be looped back to the terrestrial terminal. The terrestrial terminal may detect the looped back secondary signals, and in response, determine the presence of the OCI and that the supervisory signals were rerouted by the OCI.

There is provided an OTDR receive device and an OTDR system comprising an OTDR receive device wherein the OTDR unit and the OTDR receive device are to be connected at opposite ends of an optical fiber link under test. The OTDR receive device comprises means for the OTDR system to detect an established connectivity between the OTDR unit and the OTDR receive device via the optical fiber link under test and a status indicator to notify a user of the receive device of the connectivity status and optionally an OTDR measurement status. Connectivity detection allows to check for continuity between the OTDR unit and the OTDR receive device before launching an OTDR measurement. A user of the OTDR unit does not need to communicate with the user of the OTDR receive device to know when to start the acquisition.