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: 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: 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: 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: A line monitoring system may include a laser source to launch a plurality of pulsed probe signals; an optical transmission system, comprising a plurality of loopbacks, to receive the plurality of pulsed probe signals, and direct the plurality of pulsed probe signals through the plurality of loopbacks. The system may include a receiver to receive a plurality of return signals, derived from the plurality of pulsed probe signals from the transmission system, and a perturbance detection system, coupled to the receiver, to measure a phase difference between a polarization of a pair of return signals of the plurality of return signals. The pair of return signals may be received from a pair of loopbacks of the plurality of loopbacks, from a first loopback and a second return signal from a second loopback. The perturbance detection system may determine a location of a perturbation, based upon the phase difference.

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: 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: An undersea fiber optic cable routing architecture including a branching unit coupled to three trunk cables capable of switching individual fibers in each fiber pair within a cable to either of the other two cables. The branching unit comprises a plurality of optical switches and a controller for receiving remote command signals and configuring the optical switches in accordance with the remote command signals.

Abstract: An undersea fiber optic cable architecture including a beach manhole (BMH) installed at a terrestrial site, a terrestrial station connected to the BMH by a terrestrial fiber optic cable, a first landing cable extending from the BMH into territorial waters adjacent the terrestrial site and connected to a first enhanced branching unit (EBU) located in the territorial waters, a second landing cable extending from the BMH into the territorial waters and connected to a second EBU located in the territorial waters, a recovery path cable connecting the first EBU to the second EBU, a first trunk cable extending from the first EBU into international waters, and a second trunk cable extending from the second EBU into the international waters.

Abstract: A distributed acoustic sensing system. The DAS system may include a distributed acoustic sensing (DAS) station, comprising: a DAS transmitter, arranged to launch an outbound DAS signal through an optical fiber, over at least one span; a DAS receiver, arranged to receive a backscatter Rayleigh signal, based upon the DAS signal; and at least one component, coupled to the DAS transmitter, the DAS receiver, or both, and arranged to increase a sensitivity for sensing of the DAS system.

Abstract: A sensing system may include a distributed acoustic sensing (DAS) station to launch a DAS signal as an outbound DAS signal, as well as a plurality of DAS loopback assemblies, arranged along a plurality of spans. The plurality of DAS loopback assemblies may be arranged to separately process the outbound DAS signal, and return to the DAS station, the outbound DAS signal, as a return DAS signal that comprises a backscattered Rayleigh signal. As such, a given DAS loopback assembly of the plurality of DAS loopback assemblies may include an Erbium-Doped Fiber Amplifier (EDFA) that is arranged to compensate the loss from Rayleigh scattering of the DAS signal, and a filter device having an optical filtering function that is arranged to selectively send back just a sensing wavelength of the DAS signal.

Abstract: A system may include a distributed acoustic sensing (DAS) station, comprising a DAS transmitter to launch an outbound DAS signal in a first direction, over at least one span of an optical communications link. The system may further include a DAS receiver to receive a backscattered Rayleigh signal, based upon the outbound DAS signal, wherein the DAS signal is transmitted at least in part over a D? fiber.

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: 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 herein are undersea optical cable connection assemblies and systems. In some embodiments, a retainer is operable to arrange a plurality of SCFs and a plurality of microsplints, the retainer including a main body having a first section and a second section. The retainer may further include a first channel and a second channel extending through the first section, wherein a first set of SCFs extend through the first channel, and wherein a second set of SCFs extend through the second channel. The retainer may further include a third channel and a fourth channel extending through the first section, wherein a first set of microsplints extends through the third channel, and wherein a second set of microsplints extends through the fourth channel. A third set of microsplints extends through the third channel, wherein the first and third sets of microsplints are separated from one another by a padding layer.

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: An undersea fiber optic cable routing architecture including a branching unit coupled to three trunk cables capable of switching individual fibers in each fiber pair within a cable to either of the other two cables. The branching unit comprises a plurality of optical switches and a controller for receiving remote command signals and configuring the optical switches in accordance with the remote command signals.

Abstract: Provided are optical communication signal recovery techniques and a submarine optical communication recovery device may include a number of inputs, a number of outputs and a number of optical switch modules. Each input may be operable to connect to a respective optical fiber of a submarine fiber optic cable, and a number of the optical fibers carry optical signals and at least one optical fiber of the plurality of optical fibers is an unusable optical path that is unable to carry a usable optical signal. Each output may couple to another respective optical fiber, and a number of the outputs may be designated as impaired outputs. Each optical switch module of the number of optical switch modules may be operable to connect an input of the number of inputs coupled to the unusable optical path to an impaired output of the number of the impaired outputs.

Abstract: An undersea fiber optic cable architecture including a beach manhole (BMH) installed at a terrestrial site, a terrestrial station connected to the BMH by a terrestrial fiber optic cable, a first landing cable extending from the BMH into territorial waters adjacent the terrestrial site and connected to a first enhanced branching unit (EBU) located in the territorial waters, a second landing cable extending from the BMH into the territorial waters and connected to a second EBU located in the territorial waters, a recovery path cable connecting the first EBU to the second EBU, a first trunk cable extending from the first EBU into international waters, and a second trunk cable extending from the second EBU into the international waters.

Abstract: Techniques for managing gain equalization error in optical communication systems are provided. For example, a multi-stage gain correction filter may be configured to at least correct gain equalization error produced by filters with insufficient resolution, for example, conventional non-reflective gain correction technology used in the optical communication systems. The multi-stage filter may include at least a broadband gain correction filter to correct gain equalization error in most of the transmission bandwidth and a narrow band gain correction filter to correction error in a narrow region of the bandwidth. One or more of the multi-stage filters may be implemented in the repeaters of the system (which may be referred to as hybrid GFFs) or may be included in a standalone body (which may be referred to as hybrid GEFs).