Abstract: Disclosed is a joint assembly for an optical cable. In some embodiments, the joint assembly may include a termination assembly adjacent to a joint, enclosed in a boot assembly, wherein the termination assembly electrically connects, or grounds, a first optical cable and a second optical cable. The termination assembly may include a heat shrink layer surrounding a core of the optical cable, wherein the core comprises a plurality of fibers surrounded by a plurality of strength members, and a first tape layer formed around the heat shrink layer. The termination assembly may further include a non-metallic gripping layer formed over the first tape layer, a second tape layer formed over the non-metallic gripping layer, and a non-metallic material formed over the second tape layer.

Abstract: This application describes techniques for testing fiber optic telecommunication systems, such as undersea fiber optic cable systems. Testing terminals may be deployed at a location of terminating equipment for a fiber optic cable. The testing terminals may be operated remotely. The testing terminals may be configured to programmatically test the cable by loading one or more tests and automatically configure the cable's transmitters and receivers based on predetermined loading schemes selected based on the tests to be performed. The testing terminals may iterate over channels and fiber pairs of the cable and may use back-to-back tests to remove artifacts from test results. Using the described techniques, a cable's channels and fiber pairs can be fully characterized in the amount of time afforded for a typical testing schedule, which was not generally possible using conventional testing.

Abstract: Disclosed is a cable with dual metal conductor structure. In some embodiments, an optical cable includes hollow buffer tube having a plurality of optical fibers therein, and a first plurality of layered strength members surrounding the hollow buffer tube. The optical cable may further include a conductor surrounding the first plurality of layered strength members, wherein the conductor includes a first metal layer surrounded by a second metal layer, and an outer insulating jacket surrounding the conductor.

Abstract: A monitoring system. The monitoring system may include an optical receiver configured to receive an optical signal, the receiver comprising a plurality of equalizers to partition the optical signal over a plurality of optical channels corresponding to a plurality of optical wavelengths. The monitoring system may also include an analysis component, coupled to the receiver, comprising logic, where the logic is configured to construct a plurality of sensor matrices, corresponding to the plurality of optical channels, based upon the optical signal, after reception at the receiver; determine, using the plurality of sensor matrices, a correlation between at least one pair of sensor matrices corresponding to at least one pair of optical channels of the plurality of optical channels; and determine a location of a perturbation, external to the transmission system, based upon the correlation.

Abstract: A method and a system for monitoring an optical transmission path in an optical transmission system. A signal is transmitted on a portion of the optical transmission path. The optical transmission path includes a plurality of portions. A clock synchronization signal in a plurality of clock synchronization signals is assigned to the transmitted signal. A backscattered signal is received. The backscattered signal is generated by the portion of the optical transmission path in response to the signal being transmitted on the portion of the optical transmission path. Based on the assigned clock synchronization signal, the portion of the optical transmission path is monitored by analyzing the backscattered signal to determine a presence of an interference on the portion of the optical transmission path.

Abstract: Provided are techniques, devices and systems that enable updating of a reportable parameter table database when a reconfigured optical communication path is formed by switching performed by a branching unit in an undersea optical communication transmission system. A processor may obtain system attributes of each respective segment of a number of segments of the reconfigured optical communication path from a first end point to a second endpoint. The system attributes of each respective segment of the number of segments may be evaluated from the first end point to the second endpoint of the reconfigured optical communication path. A reportable parameter table may be generated based on the evaluated system attributes that includes a listing of operational and structural parameters of system from the first endpoint to the second endpoint of the reconfigured optical communication path.

Abstract: Disclosed are techniques and amplifier stages that include wave division multiplexers, semiconductor optical amplifiers and wave division demultiplexers that amplify optical signals. An input optical signal having a first bandwidth is partitioned into a plurality of subband optical signals by thin film filters tuned to a selected bandwidth that is less than the first bandwidth. Each of the plurality of subband optical signals has a bandwidth that is a portion of the first bandwidth. Each subband optical signal is input into a semiconductor optical amplifier that is tuned to the respective portion of the first bandwidth that corresponds to the subband optical signal. The combination of the partitioned input optical signal and tuned semiconductor optical amplifiers provides improved optical signal transmission performance by reducing polarization dependent gain.

Abstract: Methods of measuring an anomaly, any induced change in physical parameters such as strain, temperature, and so forth, in an optical fiber. One method may include launching a plurality of probe pulses from a probe source; recording a Brillouin scattering spectrum from a plurality of reflection signals generated in the optical fiber, responsive to the plurality of probe pulses; determining a relative motion between the optical fiber and the anomaly during the recording the Brillouin back-scattering spectrum; and dynamically adjusting the Brillouin back-scattering spectrum according to the relative motion, or performing an adjustment of the Brillouin back-scattering spectrum after acquisition of the Brillouin back-scattering spectrum.

Abstract: Apparatus, systems, and techniques for extending distributed acoustic sensing (DAS) range in undersea optical cables over multiple spans, as well as providing span-specific DAS information, are provided.

Abstract: Techniques for extending distributed acoustic sensing (DAS) range in undersea optical cables are provided. For example, DAS range can be extended by transmitting and amplifying a DAS signal along multiple spans of a first optical fiber, routing or bypassing the DAS signal from the first optical fiber to a second optical fiber different from the first fiber via a high-loss loopback architecture, and returning and amplifying the DAS signal along the same multiple spans back to a DAS device. The DAS device may then receive and process the DAS signal to detect any changes in the DAS environment. The loopback configuration may be based on different types of loopback architecture.

Abstract: An apparatus for managing optical subsea communications system may include a plurality of fiber interface modules (FIM), wherein a given FIM comprises a receive part, and a transmit part. The transmit part may include two normally closed switches, wherein a first switch of the two normally closed switches is coupled to a line monitoring equipment (LME) TX port, and wherein a second switch of the two normally closed switches is coupled to a line terminating equipment (LTE) TX port.

Abstract: Submarine cable branching units with fiber pair switching configured to allow any number of trunk cable fiber pairs to access the optical spectrum any number of branch cable fiber pairs. Access to a particular branch terminal is not limited to predefined subset of the trunk fiber pairs. This approach allows fewer branch cable fiber pairs to be equipped in each branching unit, reducing system cost, simplifies system planning and provides flexible routing of overall trunk cable capacity.

Abstract: An apparatus for subsea environment sensing. In one aspect, the apparatus may include a repeater assembly, disposed in an optical repeater; and an environmental sensor assembly, disposed proximate to the repeater assembly, the environmental sensor assembly being coupled to receive power from the repeater assembly over an optical link.

Abstract: Techniques for extending distributed acoustic sensing (DAS) range in undersea optical cables are provided. For example, DAS range can be extended by transmitting and amplifying a DAS signal along multiple spans of a first optical fiber, routing or bypassing the DAS signal from the first optical fiber to a second optical fiber different from the first fiber via a high-loss loopback architecture, and returning and amplifying the DAS signal along the same multiple spans back to a DAS device. The DAS device may then receive and process the DAS signal to detect any changes in the DAS environment. The loopback configuration may be based on different types of loopback architecture.

Abstract: Techniques for improving gain equalization in C- and L-band (“C+L”) erbium-doped fiber amplifier (EDFAs) are provided. For example, the C- and L-band amplification sections of a C+L EDFA may be separated and configured in a parallel arrangement or a serial arrangement. For both the parallel and serial arrangements, the C- and L-band amplification sections may share a common gain flattening filter (GFF) or each amplification section may include and employ a separate GFF. Moreover, in some examples, an “interstage” L-band GFF may be located before or upstream of the L-band amplification section such that the L-band optical signal is gain-equalized or flattened prior to the L-band amplification section amplifying the L-band.

Abstract: Disclosed are approaches for forming a semiconductor device. In some embodiments, a method may include providing a patterned hardmask over a substrate, and providing, from an ion source, a plasma treatment to a first section of the patterned hardmask, wherein a second section of the patterned hardmask does not receive the plasma treatment. The method may further include etching the substrate to form a plurality of fins in the substrate, wherein the first section of the patterned hardmask is etched faster than the second section of the patterned hardmask.

Abstract: An apparatus for subsea environment sensing. In one aspect, the apparatus may include a repeater assembly, disposed in an optical repeater; and an environmental sensor assembly, disposed proximate to the repeater assembly, the environmental sensor assembly being coupled to receive power from the repeater assembly over an optical link.

Abstract: A docking/charging module for an undersea autonomous vehicle comprises a housing allowing the undersea autonomous vehicle to dock, thereby establishing both a data connection and a power connection between the module and the vehicle, the module being equipped with the battery which is charged from an undersea cable having a power conductor which may charge the undersea autonomous vehicle via the power connection when the undersea autonomous vehicle is docked with or in proximity to the docking/charging module.

Abstract: Disclosed are a system and techniques to determine a color of an optical fiber in a fiber optic cable. A spectrophotometer camera may obtain a color value of the optical fiber. A fiber adaptor is operable to hold a single optical fiber of a fiber optic cable in a field of view of the spectrophotometer camera. A memory storing instructions that, when executed by a processor, enable identifying a color of the optical fiber. The color value may be compared to a color value of a number of reference colors. A color match score value may be generated for the color value with respect to each reference color. A confidence value may be obtained for a pair of color match scores that are closest in score value. Based on the confidence value, one of the reference colors is identified as a color of the optical fiber.

Abstract: Techniques for improving gain equalization in C- and L-band (“C+L”) erbium-doped fiber amplifier (EDFAs) are provided. For example, the C- and L-band amplification sections of a C+L EDFA may be separated and configured in a parallel arrangement or a serial arrangement. For both the parallel and serial arrangements, the C- and L-band amplification sections may share a common gain flattening filter (GFF) or each amplification section may include and employ a separate GFF. Moreover, in some examples, an “interstage” L-band GFF may be located before or upstream of the L-band amplification section such that the L-band optical signal is gain-equalized or flattened prior to the L-band amplification section amplifying the L-band.