Abstract: A method to determine the types of optical fibers forming a link of an optical communication network. By scanning a signal's bit error rate at a receiver end, as a function of a pre-dispersion applied to a signal at a transmitter end, local minimums in the curve indicate the presence of amplifiers, and therefore fiber span extremities. By determining the accumulated dispersion at each fiber extremity, a ratio of dispersion per span length can be obtained and the span's coefficient of chromatic dispersion be inferred, thereby identifying the type of fiber. Alternatively, a signal's signal-to-noise ratio can be scanned, instead of its bit error rate. In a typical network, the required instrumentation is pre-existing.

Abstract: A system for dispersion compensation for a fibered communication path, the system being configured for connection with a node of the fibered communication path. The system includes a controller; a wavelength selective switch (WSS) communicatively coupled to the controller, the WSS being configured for operatively coupling to at least one fiber of the fibered communication path; and dispersion compensation modules (DCM) optically connected to the WSS. Each DCM is configured to provide a particular compensation for dispersion in light received therein, the controller being configured to determine, for each wavelength received from the at least one fiber, an accumulated dispersion, and cause, for each wavelength received from the at least one fiber, the WSS to send each wavelength to a particular one of the plurality of DCMs having the particular compensation corresponding to the accumulated dispersion of each wavelength.

Abstract: Filter media comprising non-woven fiber webs having one or more advantageous physical properties are generally described. In some embodiments, a filter media and/or non-woven fiber web described herein comprises a combination of fibers that results in enhanced physical properties. For example, the non-woven fiber web may comprise a combination of fiber types that is advantageous, such as a combination comprising fibrillated fibers, glass fibers, and/or binder fibers. In some cases, the filter media and/or non-woven fiber web comprising the combination of fibers may be formed into undulations (e.g., by a creping and/or microcreping process) to further enhance the physical properties of the filter media and/or non-woven fiber.

Abstract: An optical fiber configured to improve the pump conversion efficiency of an L-band fiber amplifier which uses the multimode pump source. By directly absorbing multimode light including 915 nm, an active fiber core region co-doped with both erbium and ytterbium can provide gain to the L-band signals via stimulated emission. The unwanted C-band amplified spontaneous emission (ASE) light generate from this active fiber core region can be absorbed by another active fiber core region doped with erbium, then provides additional gain to the L-band signals. Active regions and cladding can be configured to match a given spatial mode of the optical signal. Signal-pump combiners with end-coupling or side coupling can be used.

Abstract: The disclosed systems and methods for optical filter fault localization. The optical filter fault localization is based on: i) determining an accumulated noise density at frequencies where ASE noise is filtered out by a faulty optical filter in an optical signal; ii) comparing the accumulated noise density with predicted accumulated noise densities, the predicted accumulated noise densities representing noises predicted from a plurality of optical filters to a receiver; and iii) determining, based on the comparison of the accumulated noise density and the predicted accumulated noise densities, a location of the faulty optical filter.

Abstract: The disclosed systems and methods for detecting mirror crosstalk between frequency bands equally above and below the center frequency of a Digital Subcarrier Multiplexing system include: a transmitter configured to insert zero-power symbols on half the frequency bands below center frequency, and insert other zero-power symbols, partially overlapping in time with the first zero-power symbols, on the other half of the frequency bands above center frequency. A receiver zeroes out ASE and other noises during the overlapping portion of all the zero-power symbols, then uses the power detected during the remaining portion of each zero-power symbol in each frequency band to accurately evaluate the mirror crosstalk from the corresponding frequency band on the opposite side of center frequency.

Abstract: A system for laser phase noise compensation for a fibered communication path, the system being configured for connection with a node of the fibered communication path, including at least one signal splitter optically coupled to a laser source of the fibered communication path, the at least one signal splitter having two output communication path, the communication paths having a path difference therebetween; an integrated coherent receiver (ICR) optically coupled to the first output communication path and the second output communication path; and a digital signal processor (DSP) communicatively connected to the ICR, the ICR being configured to determine, based signals received from the first and second output communication paths, at least one phase noise indication related to phase noise of the laser source, the DSP being configured to determine an estimated laser phase noise based on at least the at least one phase noise indication.

Abstract: Aspects of the disclosure provide a method of a LiDAR system to determine the distance of an object from the LiDAR system. Embodiments of the LiDAR system can use a coarse estimate of the distance of an object from the LiDAR system which is then used by a fast search to determine an estimate of the distance of an object from the LiDAR system within a precision threshold. In some embodiments the LiDAR system can use adaptive precision when determining the distance of an object from the LiDAR system.

Abstract: Aspects of the disclosure provide for methods and systems for feedback control of mode MUX and DEMUX. An aspect of the disclosure provides for a method associated with a mode MUX. The method includes modulating each WDM signal of a first set of WDM signals with a pilot tone of different frequency. The method further includes spatially multiplexing the first set of WDM signals to generate a multi-mode signal. The method further includes detecting the pilot tones from the multi-mode signal. The method further includes tuning the mode MUX based on the detecting. Another aspect of the disclosure provides for a method associated with a mode DEMUX. The method includes spatially demultiplexing a multi-mode signal into a set of WDM signals. The method further incudes detecting pilot tones from the set of WDM signals and tuning the mode DEMUX based on the detecting.

Abstract: Battery separators, and lead-acid batteries comprising battery separators, are generally provided. In some embodiments, the battery separators described herein have one or more features that enhance their suitability for various applications (e.g., lead-acid battery applications). In one embodiment, a battery separator described herein comprises at least two phases. In some cases, each phase may have a one or more features that result in a battery separator having enhanced physical properties. For example, the dual-phase battery separator may exhibit reduced electrical and ionic resistance, enhanced acid filling capacity, reduced acid stratification, and enhanced thermal and oxidative stability compared to conventional battery separators.

Abstract: A method for inspecting fibered optical communication paths. The method includes causing an acoustic signal generator near a fibered optical path to produce an acoustic signal; causing a laser to emit at least one optical pulse into the at least one fibered optical path at an emission time; detecting a plurality of reflected optical signals, each reflected optical signal having an arrival time; determining a distance traveled by each of the plurality of reflected optical signals, in which the distance traveled by a given reflected signal is determined at least in part on the arrival time of the given reflected signal and the emission time of the at least one optical pulse; and detecting for at least one distance traveled by the given reflected signal, a phase oscillation induced at least in part by the acoustic signal.

Abstract: Systems and methods for longitudinal performance monitoring of an optical communication line communicably connecting a transmitting device to a receiving device for transmitting a signal therebetween. The method comprises receiving the signal at the receiving device, the signal having been affected by propagative impairments accumulated along the optical communication line, generating, at the receiving device, a linear signal based on the received signal, generating, based on the linear signal, a plurality of signal templates, and determining correlation values between the received signal and each signal template of the plurality of signal templates, each correlation value being indicative of a local longitudinal performance of the optical communication line.

Abstract: The disclosed systems, structures, and methods are directed to risk assessment of an optical network. A simulation framework includes a risk map engine including a performance prediction engine that generates a simulation of the optical network based at least in part on an input network topology and/or service map. The prediction performance engine runs the simulation to predict, based at least in part on received network telemetry data, direct and indirect impacts on the optical network of a risk factor represented in a what-if scenario. The risk map engine includes a risk assessment engine that determines a risk associated with the risk factor based at least in part on the predicted direct and indirect impacts and on a likelihood of occurrence of the risk factor. The risk assessment engine generates a risk map showing aggregate risks to the optical network from a plurality of risk factors.

Abstract: Systems and methods are described in an optical network. A system includes a first wavelength selector system having a first input port and a first output port, the first input port configured to receive a first set of multi-wavelength signals and the first output port configured to output a second set of multi-wavelength signals, the second set of multi-wavelength signals being a subset of the first set of multi-wavelength signals; a second wavelength selector system having a second input port and a second output port, the second input port configured to receive the second set of multi-wavelength signals and the second output port configured to output a final optical signal from the second set of multi-wavelength signals; and a controller coupled to the first wavelength selector system and the second wavelength selector system.

Abstract: Systems and methods are described in an optical network. A system includes a first wavelength selector system having a first input port and a first output port, the first input port configured to receive a first set of multi-wavelength signals and the first output port configured to output a second set of multi-wavelength signals, the second set of multi-wavelength signals being a subset of the first set of multi-wavelength signals; a second wavelength selector system having a second input port and a second output port, the second input port configured to receive the second set of multi-wavelength signals and the second output port configured to output a final optical signal from the second set of multi-wavelength signals; and a controller coupled to the first wavelength selector system and the second wavelength selector system.

Abstract: The disclosed systems and methods are directed to monitor optical performance comprising receiving optical channel signals, wherein the optical channel signals are superimposed with pilot tone (PT) signals, operating a local oscillator (LO) including a tunable laser in a coarse scanning mode and a fine scanning mode and generate different LO signals in accordance with the mode in which the LO is being operated, combining the optical channel signals with at least one LO signal generated by the LO and generating a combined optical signal, detecting and converting the combined optical signal into an electrical signal, amplifying the electrical signal, converting the amplified electrical signal into a digital signal, processing the digital signal and extracting channel specific information included in the PT signals, computing channel power based on the channel specific information, and maintaining a management table.

Abstract: The disclosed systems, structures, and methods are directed to an optical transceiver, employing a first optical time domain reflectometer (OTDR) module configured to generate a first OTDR signal, and a second OTDR signal, the second OTDR signal being a delayed version of the first OTDR signal, a first optical supervisory channel (OSC) transmitter configured to generate a first OSC signal, and a second OSC signal, the second OSC signal being a delayed version of the first OSC signal, a first wavelength division multiplexer (WDM) configured to transmit the first OSC signal interleaved with the first OTDR signal on a first optical fiber and a second WDM configured to transmit the second OSC signal interleaved with the second OTDR signal on a second optical fiber.

Abstract: Methods and devices that provide a variable-bandwidth optical filter with frequency tuning are disclosed. A universal variable bandwidth optical filter architecture is disclosed, based on microring resonators that can vary both operation wavelength and bandwidth with no extra complexity relative to conventional wavelength tunable filters. The filter architecture provides a universal filter design for any arbitrary shape of filter response, such as second-order, fourth-order, sixth-order, and so on. The filter characteristics—insertion loss, in-band ripple, and out-of-band rejection level—may be maintained over the bandwidth tuning range. There is no need for extra heaters to tune the filter's operating bandwidth, as the same heaters used to tune the filter frequency can be used to tune filter bandwidth. The device can be used as an add/drop filter.

Abstract: Methods and devices that provide a variable-bandwidth optical filter with frequency tuning are disclosed. A universal variable bandwidth optical filter architecture is disclosed, based on microring resonators that can vary both operation wavelength and bandwidth with no extra complexity relative to conventional wavelength tunable filters. The filter architecture provides a universal filter design for any arbitrary shape of filter response, such as second-order, fourth-order, sixth-order, and so on. The filter characteristics—insertion loss, in-band ripple, and out-of-band rejection level—may be maintained over the bandwidth tuning range. There is no need for extra heaters to tune the filter's operating bandwidth, as the same heaters used to tune the filter frequency can be used to tune filter bandwidth. The device can be used as an add/drop filter.

Abstract: Methods and devices for power imbalance compensation and calibration of a coherent transmitter or transceiver are described. A pilot tone is combined with a digital data signal such that relative amplitudes of the pilot tone in each of four transmitted optical data channels may be detected by a pilot tone detector and used to calculate any power imbalances between I/Q phase channels and/or X/Y polarized channels of the transmitter. The pilot tone detector applies gain to the data signal of the transmitter to compensate for any calculated power imbalances. Because the pilot tone is combined with the digital data signal, its amplitude in each received channel is proportional to the data signal power of that channel.