Abstract: The disclosure is directed to an optical telecommunications system which includes a central node and a plurality of user nodes. The central node provides the light necessary to enable communication between the user nodes. Within the central node is a multi-wavelength source, providing lights at different wavelengths, along with a wavelength selector. The wavelength selector selects one of the lights at different wavelengths from the multi-wavelength source for delivery to the user nodes such that the user nodes then modulate this light for transmission between nodes.

Abstract: In wavelength division multiplexing (WDM) systems, one optical multiplexing section (OMS) can support several channels. During a network reconfiguration, the number or channel index of the channels in the OMS may change, which may result in a change in gain for other channels in the OMS due to the channel loading dependant gain properties of many optical amplifiers. Equalization is therefore required in order to reduce power excursion for the channels in the OMS. Using a model for the channel loading dependent gain of optical amplifiers, equalization may be performed more quickly than using measurement-based equalization methods. The model predicts the change in gain for the channels in an OMS following network reconfiguration, and allows for an equalizer to quickly or pre-emptively adjust for the changes. This model may include an artificial neural network, which is trained using some of the possible channel loading conditions for the OMS.

Abstract: The disclosed systems, structures, and methods are directed to monitoring performance of optical networks. Transmitted and received optical channel signal has both low-power gaps and an amplitude modulation pilot tone applied. The low-power gaps are applied at a gap frequency with gap power being lower than a signal power of the optical channel signal. The pilot tone is applied to the optical channel signal at a pilot tone modulation frequency, which is different from the gap frequency. Described methods include determining pilot tone modulation depth based on detected gap power in low-power gaps of the received optical channel signal. Amplifier spontaneous emission and nonlinear noise in optical link are detected separately. This permits determining and monitoring of optical signal-to-noise ratio.

Abstract: Methods and apparatus are provided for wavelength control of multiple independent laser sources to reduce relative wavelength drift between the different laser sources. According to some aspects, multiple laser wavelength control is provided using a multi-line source as a wavelength reference. According to other aspects, multiple laser wavelength control is provided using a single wavelength sensing device. The multiple independent laser sources could generate the constituent optical channels of a super-channel. Benefits could include reduced guard band width and increased spectral efficiency within the super-channel.

Abstract: An embodiment method includes multiplexing light emitted by the plurality of optical transmitters to provide a multiplexed optical signal; propagating the multiplexed optical signal through an optical interleaver from a first port thereof to a combined port thereof and back to a second port thereof; and detecting an optical signal at the second port of the optical interleaver.

Abstract: The present disclosure relates to a method, an apparatus and a system for monitoring performance of optical network equipment. The method comprises receiving an optical channel signal comprising a first pilot tone in a first spectral sub-band of the optical channel signal and a second pilot tone in a second spectral sub-band of the optical channel signal, the first and the second spectral sub-bands being on opposite sides of a reference frequency of the optical channel signal. The performance of the optical network equipment is monitored based on a power mismatch between the first and second pilot tones of the received optical channel signal. An apparatus and a system for monitoring performance of the optical network equipment are also described.

Abstract: In some examples, an apparatus receives a first measurement of a plurality of wavelength channels obtained at a first location of an optical medium, and a second measurement of the plurality of wavelength channels obtained at a second location of the optical medium. The apparatus computes a value relating to dispersion in the optical medium by correlating the first measurement and the second measurement.

Abstract: The present disclosure includes methods and systems in which idle tones are added at an ingress and terminated at an egress of a given fiberoptic communication link between ROADM nodes. An equalization process can be performed across the spectrum of available wavelength channels and then a determination can be made of a number of channels that can be added or dropped at a given time that meet a maximum threshold for change in power of the channels in the available wavelength. As channels without information-carrying signals are filled with idle tones, the stability of the optical system can be improved as there is less variability in power change when all of the channels have a substantially similar nominal power and a signal on one or more of those channels are added or removed.

Abstract: Systems and methods for applying a pilot tone to multiple spectral bands are provided. An initial signal is divided into multiple spectral bands. A pilot tone is applied to each of the spectral bands, and then the signals are again combined for transmission. The pilot tones differ in some way, for example in phase or frequency.

Abstract: A monitoring and calibration apparatus for an optical networking device such as ROADM is provided. Reflectors are integrated into the device, for example at the ends of optical interconnect cables. The reflectors reflect light in specific monitoring wavelengths and pass other wavelengths such as those used for communication. A light source emits monitoring light which is reflected by the reflector and measured by a detector to measure the integrity of optical paths. The optical paths can include optical cables and cable connectors. Path integrity between different modules of the device can therefore be monitored. Multiple reflectors, reflecting light in different wavelengths, can be placed in series along the same optical path and used to monitor multiple segments of the path. A wavelength selective switch (WSS) of the device can be used to route monitoring light to different optical paths. The WSS also operates to route communication signals in the device.

Abstract: In various aspects, an optical connector with a built-in photodetector for detecting light in the optical connector; an adapter for detachably receiving an optical connector, comprising an electrode configured to electrically contact an electrode of the optical connector; a connection apparatus comprising an arrangement of adapters for detachably receiving a plurality of optical connectors, each adapter comprising an electrode configured to electrically contact an electrode of the respective optical connector; a system with an interface configured to make an optical connection with an optical connector and a processing unit configured to receive from the connector an indication and to generate a feedback signal indicative of said indication; and/or an optical connector responsive to light to generate an electrical signal is provided.

Abstract: An optical circuit switching matrix includes a plurality of optical ports, each optical port being optically coupled to a respective one of a plurality of user nodes and an optical coupler having at least one input port optically coupled to the plurality of optical ports, and an output port. The optical circuit switching matrix also includes a wavelength demultiplexer having an input optically coupled to the output port of the optical coupler, and a plurality of output ports, each output port being optically coupled to a respective one of the plurality of optical ports.

Abstract: A system monitors optical performance of an optical link within an optical network. The system includes an optical transmitter having an expanded-spectrum pilot-tone modulator for modulating an expanded-spectrum pilot tone onto a high-speed data signal to generate an expanded-spectrum optical signal and an optical receiver for receiving the expanded-spectrum optical signal and for detecting and decoding the expanded-spectrum pilot tone to enable monitoring of the optical performance of the optical link.

Abstract: The application provides a method for measuring a dispersion coefficient of an optical fiber. A network device sends a first optical supervisory channel (OSC) measurement signal and a second OSC measurement signal, where wavelengths of the first OSC measurement signal and the second OSC measurement signal are different. The network device receives the returned first OSC measurement signal and second OSC measurement signal, where the first OSC measurement signal and the second OSC measurement signal are transmitted through a first optical fiber and a second optical fiber to return to the network device, and the first optical fiber and the second optical fiber are a to-be-tested optical fiber. The network device determines a delay difference between the received first OSC measurement signal and second OSC measurement signal. The network device determines a dispersion coefficient of the to-be-tested optical fiber based on the delay difference.

Abstract: In wavelength division multiplexing (WDM) systems, one optical multiplexing section (OMS) can support several channels. During a network reconfiguration, the number or channel index of the channels in the OMS may change, which may result in a change in gain for other channels in the OMS due to the channel loading dependant gain properties of many optical amplifiers. Equalization is therefore required in order to reduce power excursion for the channels in the OMS. Using a model for the channel loading dependent gain of optical amplifiers, equalization may be performed more quickly than using measurement-based equalization methods. The model predicts the change in gain for the channels in an OMS following network reconfiguration, and allows for an equalizer to quickly or pre-emptively adjust for the changes. This model may include an artificial neural network, which is trained using some of the possible channel loading conditions for the OMS.

Abstract: The disclosure is directed at a method and system for optical telecommunications performance monitoring via a dual frequency pilot tone. By applying a dual frequency pilot tone, with a first pilot tone frequency selected from a low frequency band and a second pilot tone frequency selected from a high frequency band, either simultaneously or alternatively, to a wavelength channel, one of the pilot tone frequencies may be adaptively selected to improve wavelength channel monitoring. More specifically, stimulated Raman scattering (SRS) caused crosstalk and chromatic dispersion (CD) caused pilot fading which adversely affect performance monitoring of the wavelength channel may be reduced.

Abstract: Disclosed is a battery separator, comprising two fiber regions comprising glass fibers, and a middle fiber region disposed between them comprising larger average diameter fibers and specified amounts of silica, or fine fibers, or both; and processes for making the separator. Also disclosed is a battery separator, comprising a fiber region and either one or two silica-containing region(s) adjacent thereto, each of the regions containing a specified amount of silica; and processes for making the separator. Such separators are useful, e.g., in lead-acid batteries.

Abstract: The present disclosure includes methods and systems in which idle tones are added at an ingress and terminated at an egress of a given fiberoptic communication link between ROADM nodes. An equalization process can be performed across the spectrum of available wavelength channels and then a determination can be made of a number of channels that can be added or dropped at a given time that meet a maximum threshold for change in power of the channels in the available wavelength. As channels without information-carrying signals are filled with idle tones, the stability of the optical system can be improved as there is less variability in power change when all of the channels have a substantially similar nominal power and a signal on one or more of those channels are added or removed.

Abstract: Non-woven webs that can be used as battery separators for batteries, such as lead acid batteries, are generally provided. In some embodiments, battery separators comprising a non-woven web including one or more chemical additives are provided. The chemical additives may impart beneficial properties, such as enhanced separator stability and/or battery performance. In some embodiments, the chemical additive(s) may confer resistance to oxidation, heavy metal deposition, and/or formation of short circuits during cycling of a battery including the battery separator. The respective characteristics and/or amounts of the chemical additive(s) may be selected to impart desirable properties while having relatively minimal or no adverse effects on another property of the battery separator and/or the battery.

Abstract: A monitoring and calibration apparatus for an optical networking device such as ROADM is provided. Reflectors are integrated into the device, for example at the ends of optical interconnect cables. The reflectors reflect light in specific monitoring wavelengths and pass other wavelengths such as those used for communication. A light source emits monitoring light which is reflected by the reflector and measured by a detector to measure the integrity of optical paths. The optical paths can include optical cables and cable connectors. Path integrity between different modules of the device can therefore be monitored. Multiple reflectors, reflecting light in different wavelengths, can be placed in series along the same optical path and used to monitor multiple segments of the path. A wavelength selective switch (WSS) of the device can be used to route monitoring light to different optical paths. The WSS also operates to route communication signals in the device.