Methods for, and network elements in, packet or optical transport networks are disclosed, including a network element comprising non-transitory computer readable medium storing computer-executable instructions configured as one or more software agents that when executed with computer hardware: determine a state of the network element, comprising comparing a current state of transient properties of the network element against a predetermined, expected state of the transient properties of the network element; and verify a state of other network elements or paths in the transport network by comparing a current state of one or more network-level constraints of the other network elements or paths against a predetermined, expected state of the one or more network-level constraints on the other network elements or paths. The computer hardware may further positively or negatively acknowledge received instructions to apply a configuration to the network element based on the determination and/or verification.

A method includes determining a first power level by performing a first series of measurements based on a first series of burst transmissions from an optical transmitter of an optical network unit (ONU) in an optical network. Bursts in the first series of burst transmissions include a first modified preamble. A second power level is determined by performing a second series of measurements based on a second series of optical burst transmissions. Bursts in the second series of burst transmissions include a second modified preamble. A first power level (P.sub.0) and a second power level (P.sub.1) are determined based on the first power level and the second power level and one or more additional parameters associated with transmissions from the optical transmitter are determined based on P.sub.0 and P.sub.1. Based on the additional parameters, it is determined whether the optical transmitter complies with specifications of the optical network.

A communication device used in an optical communication system, the communication device includes a mode change over device configured to switch between a learning mode for learning a normal state of an optical transmission path before operation and a monitoring mode for monitoring a state of the optical transmission path during operation, an anomaly detector configured to detect an anomaly of the optical transmission path using a prediction model determined by the learning mode when the monitoring mode is selected, and a data writer configured to extract waveform data including information related to the anomaly to output the extracted waveform data to an outside when the anomaly is detected.

Aspects of the present disclosure are directed to alternative repeater design(s) that advantageously improve signal-to-noise of distributed acoustic sensing (DAS) systems using coherent detection of Rayleigh backscatter in multi-span links including inline amplification that may be employed—for example—in undersea submarine systems. The repeater designs incorporate Rayleigh combine units (RCU) and Rayleigh drop units (RDU) to reduce Rayleigh backscatter loss as Rayleigh signal(s) is/are routed to a link that propagates the backscatter signal in an opposite direction relative to interrogation pulse(s).

Described herein is a calibration system (25) for a wavelength selective switch (1). The switch (1) is adapted for dynamically switching optical beams (5, 7) along respective trajectories between input and output ports disposed in an array (3) using a reconfigurable Liquid crystal on silicon (LCOS) spatial light modulator device (17). The calibration system (25) includes a monitor (27) for projecting an optical monitor beam (29) through at least a portion of the switch (1) onto the LCOS (17) and detecting the monitor beam (29) reflected from the LCOS (17). In response, system (25) provides a calibration signal (33) to an active correction unit (35) for applying a correction to one or more of the trajectories while maintaining a constant switching state in the LCOS (17).

An optical communication apparatus may include a frequency locking module and a signal light generation module. The frequency locking module is configured to: generate a target wavelength control signal based on an optical frequency difference indication signal and send the target wavelength control signal to the signal light generation module. The frequency locking module is further configured to generate a target electrical modulation signal based on a target optical frequency difference, a target electrical frequency difference, and to-be-transmitted bit information that are determined by using the optical frequency difference indication signal. The signal light generation module is configured to: generate third signal light based on the target wavelength control signal and the target electrical modulation signal and send the third signal light to a second optical communication apparatus.

Applications of robotics applied to patch-panels and cross-connects to improve operational processes within data centers and communications networks. Systems and architectures to perform frequent, accurate and low-cost reconfigurations and measurements of the physical network are described, thereby eliminating labor and time delays when completing routine tasks such physical network provisioning and reconfiguration.

A distribution network with point-to-multipoint architecture couples a line termination unit to a plurality of network termination units. A network termination unit includes one or more user network interfaces configured to interface with respective user equipment of respective users, a downstream packet buffer for temporary storage of data packets, a downstream packet buffer monitor configured to monitor the status of the downstream packet buffer and to generate back-pressure signals indicative for the status, wherein the status corresponds to a fill level or fill level variation of the downstream packet buffer, and an upstream transmitter configured to upstream transmit the back-pressure signals to the line termination unit to be used there for shaping and/or scheduling future downstream transmission of data packets to the one or more user network interfaces.

According to a method, when it is detected that service traffic needs to be switched from a first optical layer path to a second optical layer path, a first internet protocol (IP) link associated with the service traffic needs to be determined, and an IP link used to transmit the service traffic is adjusted from the first IP link to a second IP link; an optical layer path of the first IP link is switched from the first optical layer path to the second optical layer path after the adjustment of the IP link is completed; and the IP link used to transmit the service traffic is adjusted from the second IP link to the first IP link after the switching of the optical layer path is completed. In this way, continuity of the service traffic can be ensured.

Disclosed are an apparatus and testing methods for performing testing operations over multiple types of links and through multiple potential points of failure to segment sources of problems, which may relate to reported or actual instances of service disruption in a network communication environment. The apparatus may perform service layer testing directly via an optical link, in addition to via Ethernet service layer testing. The apparatus may further conduct tests on other layers as well, including the physical layer, the network layer, and the link layer. To facilitate efficient testing, the apparatus may integrate programmable workflow profiles that specify tests to be conducted, and may interface with a cloud platform for sharing results of the tests, providing end-to-end testing of various components and types of links (whether optical or electrical, including wired and wireless links). Results of the tests may provide guidance to resolve detected problems.