Abstract: This spatial division multiplexing (SDM) in power-limited optical communication systems. In general, an SDM optical transmission system may be configured to increase data capacity over the data capacity of a non-SDM optical transmission system while maintaining power consumption at or below that of the existing non-SDM optical transmission system. To realize such an improvement in performance without increasing power consumption, an example SDM optical transmission may be constructed by reducing system bandwidth, reducing and/or altering equipment for filtering, reducing optical amplifier spacing, reducing operational amplifier power consumption, etc. In this manner, increased data transmission performance may be realized even where available power may be strictly limited.

Abstract: A system and method consistent with the present disclosure provides for automated line monitoring system (LMS) baselining that enables capturing and updating of operational parameters specific to each repeater and associated undersea elements based on high loss loopback (HLLB) data. The captured operational parameters may then be utilized to satisfy queries targeting specific undersea elements in a Command-Response (CR) fashion. Therefore, command-response functionality may be achieved without the added cost, complexity and lifespan issues related to deploying undersea elements with on-board CR circuitry. As generally referred to herein, operational parameters include any parameter that may be derived directly or indirectly from HLLB data. Some example non-limiting examples of operational parameters include span gain loss, input power, output power, gain, and gain tilt.

Abstract: A separation duct for encompassing an elongate member. The duct includes longitudinal internal spacers extend longitudinally in a direction of a longitudinal axis of the duct. A longitudinal plane for each spacer is substantially parallel to the longitudinal plane of the other spacers. The spacers support the elongate member and resist slippage of the duct relative to the elongate member. The duct may be used to provide separation and protection for elongate members of a range of outside dimensions.

Abstract: In general, a system and method consistent with the present disclosure provides automated line monitoring using a machine learning fault classifier for determining whether a signature associated with the high loss loopback (HLLB) data matches a predetermined fault signature. The fault classifier may be applied to signatures generated in response to line monitoring signals of two different wavelengths. A fault may be reported only if the fault classifier indicates a fault in response to the signature for both wavelengths. A second fault classifier may also be used and a fault may be reported only if both the first and second fault classifiers indicate a fault in response to the signature for both wavelengths. A system consistent with the present disclosure may also, or alternatively, be configured to report the value of a pump degradation, span loss, or repeater failure fault, and may also, or alternatively, report the directionality of a span loss fault or the location of a fiber break fault.

Abstract: A system and method consistent with the present disclosure provides for automated line monitoring system (LMS) baselining that enables capturing and updating of operational parameters specific to each repeater and associated undersea elements based on high loss loopback (HLLB) data. The captured operational parameters may then be utilized to satisfy queries targeting specific undersea elements in a Command-Response (CR) fashion. Therefore, command-response functionality may be achieved without the added cost, complexity and lifespan issues related to deploying undersea elements with on-board CR circuitry. As generally referred to herein, operational parameters include any parameter that may be derived directly or indirectly from HLLB data. Some example non-limiting examples of operational parameters include span gain loss, input power, output power, gain, and gain tilt.

Abstract: A submarine optical communication system using one or more power feed converters for power delivery to repeaters. Power feed equipment located one or more a landmasses is coupled to a power conductor of an optical cable for powering repeaters coupled to cable. One or more power feed converter(s) are coupled to the power conductor for converting current from power feed equipment to a constant output current or voltage for powering other repeaters coupled to the cable. Embodiments are robust to shunts of the power conductor.

Abstract: A system and method for in-service optical signal-to-noise ratio (OSNR) testing in optical communication systems. At least one OSNR test signal is combined onto an optical path with data channels. A receiver detects the received power of the OSNR test signal and provides output data representative of the OSNR of the system.

Abstract: A separation duct for encompassing an elongate member. The duct includes longitudinal internal spacers extend longitudinally in a direction of a longitudinal axis of the duct. A longitudinal plane for each spacer is substantially parallel to the longitudinal plane of the other spacers. The spacers support the elongate member and resist slippage of the duct relative to the elongate member. The duct may be used to provide separation and protection for elongate members of a range of outside dimensions.

Abstract: A system and method for in-service optical signal-to-noise ratio (OSNR) testing in optical communication systems. At least one OSNR test signal is combined onto an optical path with data channels. A receiver detects the received power of the OSNR test signal and provides output data representative of the OSNR of the system.

Abstract: A system and method including polarization modulation of supervisory signals for reducing interference with data signals in a wavelength division multiplexed optical communication system. At least one supervisory signal for monitoring a transmission path and/or elements coupled to the transmission path is fast polarization modulated and launched with data signals onto the path. Polarization modulating of the supervisory signal reduces impact of the supervisory signal on the data signals and improves system performance.

Abstract: In general, a branching configuration used in a wavelength division multiplexed (WDM) optical communication system, consistent with an embodiment of the present disclosure, includes a branch path with two or more optical paths cross-coupled to each other to provide redundant add and/or drop channel wavelengths to a branch terminal on each cross-coupled path. Accordingly, a fault condition affecting some of the cross-coupled optical paths may occur physically downstream from the cross-coupling, e.g., within a subsea umbilical cable or associated termination equipment. However, so long as at least one of the cross-coupled optical paths remains operational, then branch terminal equipment in the branch terminal may continue to receive channel wavelengths associated with a faulted optical path via an operational optical path by virtue of cross-coupling. Thus, the cross-coupled configuration reduces or otherwise eliminates the necessity of allocating spare optical paths within the subsea umbilical cable.