Abstract: Automatic optical link calibration systems and methods include, in an optical section with an Optical Add-Drop Multiplexer (OADM) multiplexer, an OADM demultiplexer, and zero or more in-line optical amplifiers between the OADM multiplexer and the OADM demultiplexer, wherein the optical section includes integrated measurement equipment, and wherein the OADM multiplexer and the OADM demultiplexer have a route and select architecture, obtaining measurement data from the integrated measurement equipment subsequent to turn up; determining an optimal target launch power profile per fiber span in the optical section based on the measurement data; configuring channel holders at the OADM multiplexer to meet the optimal target launch power profile per fiber span; and calibrating each fiber span to determine settings of equipment at the OADM multiplexer, the OADM demultiplexer, and the zero or more in-line optical amplifiers.

Abstract: Systems and methods for preconditioning an optical spectrum through predicting optical spectral profiles in advance of capacity changes in an optical section include obtaining data associated with the optical section to model a current state of spectral loading in the optical section; responsive to a proposed capacity change in the current state of spectral loading, estimating a future state of spectral loading which includes the capacity change; and causing changes to one or more settings in the optical section to achieve an optimized spectral loading for the future state of spectral loading.

Abstract: Systems and methods for preconditioning an optical spectrum through predicting optical spectral profiles in advance of capacity changes in an optical section include obtaining data associated with the optical section to model a current state of spectral loading in the optical section; responsive to a proposed capacity change in the current state of spectral loading, estimating a future state of spectral loading which includes the capacity change; and causing changes to one or more settings in the optical section to achieve an optimized spectral loading for the future state of spectral loading.

Abstract: A method, an optical node, and an optical network include a power controller configured to bring channels in-service in parallel over multiple cascaded optical nodes quickly, efficiently, and in a non-service affecting manner. The method, node, and network utilize multiple states of a control loop that maintains a stable response in downstream optical nodes as channels are added in parallel. Further, the power controller is configured to operate independently alleviating dependencies on other power controllers and removing the need for coordination between power controllers. The method, node, and network provide efficient turn up of dense wave division multiplexing (DWDM) services which is critical to optical layer functionality including optical layer restoration.

Abstract: A frequency offset detection method in an optical spectrum measurement device, implemented by a controller, includes determining a reference optical spectrum based on expected channels and their associated spectral occupancy without extracting any information from actual received optical spectrum; obtaining a measured optical spectrum from the optical spectrum measurement device; and performing a frequency offset control loop using the reference optical spectrum and the measured optical spectrum to correct frequency offset in the optical spectrum measurement device. The optical spectrum measurement device can be an Optical Channel Monitor and the measured optical spectrum can include optical channels partially overlapping one another in Nyquist or in super-Nyquist spacing.

Abstract: A frequency offset detection method in an optical spectrum measurement device, implemented by a controller, includes determining a reference optical spectrum based on expected channels and their associated spectral occupancy without extracting any information from actual received optical spectrum; obtaining a measured optical spectrum from the optical spectrum measurement device; and performing a frequency offset control loop using the reference optical spectrum and the measured optical spectrum to correct frequency offset in the optical spectrum measurement device. The optical spectrum measurement device can be an Optical Channel Monitor and the measured optical spectrum can include optical channels partially overlapping one another in Nyquist or in super-Nyquist spacing.

Abstract: Systems and methods using a polarimetric measurement device to localize a source of one or more State of Polarization (SOP) transients affecting one or more optical fibers are disclosed. The method includes transmitting a signal into a fiber in a first direction; receiving, at the polarimetric measurement device, the signal from one of the fiber and another fiber collocated in a bundle with the fiber in a second direction; and processing data from the polarimetric measurement device to determine a location of the one or more SOP transients. The processing can include detecting a presence of the one or more SOP transients based on a first signature and its echo seen in the data; and converting a time between the echoes into a distance.

Abstract: Spectrum control systems and methods are implemented to minimize power spectral density (PSD) offsets by adjusting gain of optical amplifiers in an optical section. The optical section is a logical boundary from one optical signal access point to a next adjacent optical signal access point. The systems and methods include estimating PSD offset from a given target for a peak channel at each span in the optical section, wherein the estimated PSD offset is divided at each span into two components including a self-introduced offset and an uncompensated offset from upstream; generating, for each span, a separate controller response for the self-introduced offset and the uncompensated offset from upstream; and controlling the gain of the optical amplifiers based on the separate controller response for the self-introduced offset and the uncompensated offset from upstream, for each span.

Abstract: Systems and methods using a polarimetric measurement device to localize a source of one or more State of Polarization (SOP) transients affecting one or more optical fibers are disclosed. The method includes transmitting a signal into a fiber in a first direction; receiving, at the polarimetric measurement device, the signal from one of the fiber and another fiber collocated in a bundle with the fiber in a second direction; and processing data from the polarimetric measurement device to determine a location of the one or more SOP transients. The processing can include detecting a presence of the one or more SOP transients based on a first signature and its echo seen in the data; and converting a time between the echoes into a distance.

Abstract: Spectrum control systems and methods are implemented to minimize power spectral density (PSD) offsets by adjusting gain of optical amplifiers in an optical section. The optical section is a logical boundary from one optical signal access point to a next adjacent optical signal access point.

Abstract: A method of analysing performance of an optical fiber link. As a preliminary step, a reference trace indicative of a distributed optical performance of the optical fiber link is derived. During in-service operation of the optical fiber link, an Optical Time Domain Reflectometry (OTDR) sub-system measures an OTDR trace with Raman amplification ON, and a real-time cumulative Raman Gain profile of the optical fiber link is calculated based on the reference trace and the measured OTDR trace.

Abstract: A method, an optical node, and an optical network include a power controller configured to bring channels in-service in parallel over multiple cascaded optical nodes quickly, efficiently, and in a non-service affecting manner. The method, node, and network utilize multiple states of a control loop that maintains a stable response in downstream optical nodes as channels are added in parallel. Further, the power controller is configured to operate independently alleviating dependencies on other power controllers and removing the need for coordination between power controllers. The method, node, and network provide efficient turn up of dense wave division multiplexing (DWDM) services which is critical to optical layer functionality including optical layer restoration.

Abstract: A method of analysing performance of an optical fiber link. As a preliminary step, a reference trace indicative of a distributed optical performance of the optical fiber link is derived. During in-service operation of the optical fiber link, an Optical Time Domain Reflectometry (OTDR) sub-system measures an OTDR trace with Raman amplification ON, and a real-time cumulative Raman Gain profile of the optical fiber link is calculated based on the reference trace and the measured OTDR trace.

Abstract: A method, an optical node, and an optical network include a power controller configured to bring channels in-service in parallel over multiple cascaded optical nodes quickly, efficiently, and in a non-service affecting manner. The method, node, and network utilize multiple states of a control loop that maintains a stable response in downstream optical nodes as channels are added in parallel. Further, the power controller is configured to operate independently alleviating dependencies on other power controllers and removing the need for coordination between power controllers. The method, node, and network provide efficient turn up of dense wave division multiplexing (DWDM) services which is critical to optical layer functionality including optical layer restoration.

Abstract: A method, an optical node, and an optical network include a power controller configured to bring channels in-service in parallel over multiple cascaded optical nodes quickly, efficiently, and in a non-service affecting manner. The method, node, and network utilize multiple states of a control loop that maintains a stable response in downstream optical nodes as channels are added in parallel. Further, the power controller is configured to operate independently alleviating dependencies on other power controllers and removing the need for coordination between power controllers. The method, node, and network provide efficient turn up of dense wave division multiplexing (DWDM) services which is critical to optical layer functionality including optical layer restoration.

Abstract: A substance sensor comprises a single-mode optical fibre having a core and a cladding having a lower refractive index than that of the core. A sensor material extends within the cladding towards the core. A layer of cladding is left between the sensor material and the core. The thickness (t) of the layer is sufficiently small that the sensor material lies within the evanescent wave which occurs within the cladding when optical radiation is conducted through the core. The refractive index of the sensor material varies in the presence of a substance to be sensed over a range which extends above and below the refractive index of the cladding. When its refractive index is lower than that of the cladding the sensor material operates, as far as the radiation is concerned, similarly to the cladding. However, when the refractive index of the sensor material is higher than that of the cladding the sensor material couples out some of the radiation, thereby reducing the transmissivity of the fibre.