Using pump-probe measurements on multi-span optical links may result in the determination of one or more of the following: 1) wavelength-dependent power profile and gain evolution along the optical link; 2) wavelength-dependent dispersion map; and 3) location of regions of high polarization-dependent loss (PDL) and polarization-mode dispersion (PMD). Such measurements may be a useful diagnostic for maintenance and upgrade activities on deployed cables as well as for commissioning new cables.

An oxygen sensing system comprises a substrate structured to communicate optical signals. An oxygen sensing layer is disposed on the substrate and comprises an oxygen sensing molecule in a matrix in a first unexcited state and formulated to: (a) be excited by a first optical signal to move to a second state; (b) be quenched in the second state by oxygen; and (c) emit a second optical signal corresponding to an amount of oxygen. A protective layer, disposed on the oxygen sensing layer, includes at least one of i) an oleophobic layer and ii) an anti-fouling layer. A controller is optically coupled to the substrate and structured to generate the first optical signal, receive the second optical signal and determine oxygen concentration from the second optical signal.

An oxygen sensing system comprises a substrate structured to communicate optical signals. An oxygen sensing layer is disposed on the substrate and comprises an oxygen sensing molecule in a matrix in a first unexcited state and formulated to: (a) be excited by a first optical signal to move to a second state; (b) be quenched in the second state by oxygen; and (c) emit a second optical signal corresponding to an amount of oxygen. A protective layer, disposed on the oxygen sensing layer, includes at least one of i) an oleophobic layer and ii) an anti-fouling layer. A controller is optically coupled to the substrate and structured to generate the first optical signal, receive the second optical signal and determine oxygen concentration from the second optical signal.

In embodiments, methods and systems for implementing fiber optic cable network testing using a fiber optic cable network testing platform are provided. A fiber optic cable network testing adapter assembly comprises an attachment and a port. The attachment attaches the adapter assembly to a mobile device and the port receives a fiber optic cable. A fiber optic cable network testing application receives, via a camera of the mobile device, light data from the cable. The fiber optic cable is coupled to the port to transmit the light data to the application. The application is part of the fiber optic cable network testing platform, the platform provides integrated fiber optic cable network testing. The application analyzes the light data based on a fiber optic cable network testing option to generate testing results data. The application communicates the testing results data using an interface to facilitate presenting the testing results data.

A method for measuring intermodulation produced in a measurement segment of a signal transmission path, by: producing a first. HF signal (u.sub.1(t)) and a second HF signal (u.sub.2(t)), both having a predetermined frequency progression; feeding the first HF signal (u.sub.1(t)) and the second HF signal (u.sub.2(t)) to the signal transmission path, wherein an intermodulation signal is produced, which intermodulation signal has a first intermodulation signal component (u.sub.rPIM(t)) produced in an input segment of the signal transmission path and a second intermodulation signal component (u.sub.PIM(t)) produced in the measurement segment of the signal transmission path; producing a compensation signal (u.sub.c(t)) in accordance with the first intermodulation signal component (u.sub.rPIM(t)) produced in the input segment; introducing the compensation signal (u.sub.c(t)) into the signal transmission path in order to reduce or cancel out the first intermodulation signal component (u.sub.rPIM(t)). The invention further relates to a measuring device for performing said method.

A method for measuring intermodulation produced in a measurement segment of a signal transmission path, by: producing a first. HF signal (u.sub.1(t)) and a second HF signal (u.sub.2(t)), both having a predetermined frequency progression; feeding the first HF signal (u.sub.1(t)) and the second HF signal (u.sub.2(t)) to the signal transmission path, wherein an intermodulation signal is produced, which intermodulation signal has a first intermodulation signal component (u.sub.rPIM(t)) produced in an input segment of the signal transmission path and a second intermodulation signal component (u.sub.PIM(t)) produced in the measurement segment of the signal transmission path; producing a compensation signal (u.sub.c(t)) in accordance with the first intermodulation signal component (u.sub.rPIM(t)) produced in the input segment; introducing the compensation signal (u.sub.c(t)) into the signal transmission path in order to reduce or cancel out the first intermodulation signal component (u.sub.rPIM(t)). The invention further relates to a measuring device for performing said method.

An optical network including an input to receive from an optical network light comprising plural wavelength components. An optical wavelength selective filter, optically connected to the input, extracts a first wavelength component of the plural wavelength components from the light, thereby providing a first optical signal including the first wavelength component and a second optical signal including a remainder of the plural wavelength components a light emitter to provide a modulated broadband optical signal. A first output, optically connected to the optical wavelength selective filter, receives a first portion of the second optical signal for transmission to a light detector and a second output, optically connected to optical wavelength selective filter, receives a second portion of the second optical signal for transmission to the optical network.

In one embodiment, a method includes receiving at a remote network device, power and data from a central network device, wherein the power is used to power the remote network device, performing auto-negotiation with the central network device, wherein the auto-negotiation includes operating the remote network device in a low voltage mode during fault sensing of a power circuit at the remote network device, and selecting a power operating mode, wherein selecting the power operating mode includes selecting a high voltage mode if no fault is detected during the fault sensing, the high voltage mode comprising DC (direct current) pulse power. An apparatus is also disclosed herein.

In one embodiment, a method includes receiving at a remote network device, power and data from a central network device, wherein the power is used to power the remote network device, performing auto-negotiation with the central network device, wherein the auto-negotiation includes operating the remote network device in a low voltage mode during fault sensing of a power circuit at the remote network device, and selecting a power operating mode, wherein selecting the power operating mode includes selecting a high voltage mode if no fault is detected during the fault sensing, the high voltage mode comprising DC (direct current) pulse power. An apparatus is also disclosed herein.

A method for determining network topology of a provider network includes selecting a first network element, selecting a first port on the first network element, and iteratively performing connectivity validation tests using the first port, wherein each connectivity validation test is associated with a type of network element and yields a result that indicates whether a second port on a second network element of the associated type is connected to the first port. A system for discovering topology of a network, the system comprising a topology discovery engine in operable communication with a near network element and operable to identify a first port of a far network element that is connected to a second port of the near network element by remotely altering operation of the near network element to cause the second network element to respond in a manner that identifies the first port.