Techniques for maintaining equipment of a PON include determining a current optical profile for each segment of a plurality of segments of a PON, and detecting that the current optical profile of a particular segment is outside of a designated operating range. Based on the detection, drifts over time of the optical profile of the segment and of optical profiles of one or more other segments that share respective common endpoints with the segment are determined and compared, and based on the comparison, a component of the PON (e.g., an endpoint or an optical fiber) is identified as requiring maintenance. Each segment's optical profile corresponds to characteristics of optical signals delivered over the segment (e.g., attenuation, changes in frequencies, changes in power outputs, etc.), and current optical profiles of the PON's segments may be repeatedly updated over time to continuously monitor for components that need maintenance.

Aspects of the present disclosure aim at configuring an optical time domain reflectometry (OTDR) in a central office such that the OTDR is configured to be operatively coupled with and also configured to periodically poll each fiber at defined intervals and compute/store a reflection signature that can be used to compare with future signatures received from subsequent polls of the fiber to determine a fault (e.g., a fiber cut or breakage) between the central office (CO) and one or more optical network unit (ONU) over GIS.

A transmitter can include a laser operable to output an optical signal; a digital signal processor operable to receive user data and provide electrical signals based on the data; and a modulator operable to modulate the optical signal to provide optical subcarriers based on the electrical signals. A first one of the subcarriers carriers carries first TDMA encoded information and second TDMA encoded information, such that the first TDMA encoded information is indicative of a first portion of the data and is carried by the first one of the subcarriers during a first time slot, and the second TDMA encoded information is indicative of a second portion of the data and is carried by the first one of the subcarriers during a second time slot. The first TDMA encoded information is associated with a first node remote from the transmitter and the second TDMA encoded information is associated with a second node remote from the transmitter. A second one of the subcarriers carries third information that is not TDMA encoded, the third information being associated with a third node remote from the transmitter. A receiver and system also are described.

Systems and methods for logical to physical link mapping in a fiber optic network are provided. In one implementation, a method includes receiving geographic data related to one or more fiber links in a fiber optic network; receiving logical links on the one or more fiber links; receiving results from one or more tests performed on the one or more fiber links; utilizing the results to determine a physical representation of the one or more fiber links; and displaying a network map of the fiber optic network with the physical representation.

A method and system is described. A signal indicative of a failure of a first channel within a plurality of channels of a transmission signal traversing a signal working path in a network is received. The signal working path has a headend node, a tail-end node and an intermediate node. The first channel has a frequency band and a power level prior to failing. The signal working path is associated with a protection path. The protection path includes the intermediate node, optical cross-connects, and a transmitter supplying (ASE) light. The transmitter is activated to supply the ASE light within a frequency band and having a power level corresponding to the frequency band and power level associated with the first channel. The ASE light is supplied to a cross-connect, such that the cross-connect provides a transmission signal including the ASE light.

A passive optical communication network includes two optical line terminals configured respectively to receive a communication signal from information systems and at least two optical network units configured to receive the communication signal. At least two optical switches, one part of which is connected at input to a first terminal via a primary nominal operating path and to the second terminal via a secondary path, and the other part of which is connected at input to a second terminal via a primary nominal operating path and to the first terminal via a secondary path. Each switch being connected at output to at least one optical network unit. A command controller connected to the switches and configured to control the switches such that, when a fault is detected on a primary path, the switch associated with the path is toggled.

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.

In an alien wave system, one or more transponders connected to a line system may be owned and operated by a different entity from the entity that owns and operates the line system. In such a situation, diagnosing and correcting faults, and achieving good performance, may be challenging. As such, a system and methods for interoperability in an alien wave system are provided.

Systems and methods include determining which services in a single Optical Transport Unit Cn (OTUCn) that is transmitted in an optical network via a plurality of optical carriers are affected by failed one or more optical carriers of the plurality of optical carriers; continuing to operate the single OTUCn with unaffected one or more optical carriers of the plurality of optical carriers; and adjusting some or all of the services from the failed one or more optical carriers to the unaffected one or more optical carriers.

A communication system transmits relay data through a communication path including a plurality of sections in which different communication schemes are used. A relay communication device is provided between a first section and a second section which are adjacent sections. The relay communication device includes a receiving unit receiving the relay data from the first section through a frame of a first communication scheme, and a relaying unit configuring, in a frame of a second communication scheme used to transmit the relay data to a relay destination, signal quality information representing signal quality calculated for a physical link in each of the sections through which the relay data is transmitted before arriving at the relay communication device, and outputting the frame of the second communication scheme to the second section.