Abstract: Aspects of the present disclosure are directed to alternative repeater design(s) that advantageously improve signal-to-noise of distributed acoustic sensing (DAS) systems using coherent detection of Rayleigh backscatter in multi-span links including inline amplification that may be employed—for example—in undersea submarine systems. The repeater designs incorporate Rayleigh combine units (RCU) and Rayleigh drop units (RDU) to reduce Rayleigh backscatter loss as Rayleigh signal(s) is/are routed to a link that propagates the backscatter signal in an opposite direction relative to interrogation pulse(s).

Abstract: Aspects of the present disclosure describe systems, methods, and structures for high speed frequency hopping distributed acoustic sensing using an acousto-optic modulated (AOM), gated re-circulating loop and a frequency shifted receiver local oscillator. Using the re-circulating loop controlled by the AOM to generate frequency-hopping pulse(s) increases DAS acoustic bandwidth overcomes infirmities exhibited in the art that generate multiple frequency patterns that are not suitable for long-distance DAS. Additionally, by employing frequency shifted local oscillator (LO) with asymmetric in band detection, bandwidth requirements are reduced by one half.

Abstract: Aspects of the present disclosure describe distributed fiber optic sensing (DFOS) systems, methods, and structures that advantageously overcome problems encountered when operating DFOS systems over operational telecommunications facilities namely, cross-phase modulation, and uneven amplitude profiles through the use of a novel constant amplitude coded DFOS employing out-of-band signaling.

Abstract: Aspects of the present disclosure describe optical transmission systems exhibiting low complexity fiber nonlinearity compensation provided by neural networks using lookup tables for multiplication operations.

Abstract: Aspects of the present disclosure describe systems, methods, and structures that advantageously amplify optical signals through the effect of optical pump signals generated by a multicore laser diode and multicore rare-earth doped optical fiber in optical communication with a 3D waveguide structure and a multicore input signal fiber providing a plurality of optical signals for amplification.

Abstract: Aspects of the present disclosure describe systems, methods and structures for providing semiconductor amplifiers exhibiting a low polarization-dependent gain.

Abstract: Aspects of the present disclosure describe systems, methods and structures for optical fiber nonlinearity compensation using neural networks that advantageously employ machine learning (ML) algorithms for nonlinearity compensation (NLC) that advantageously provide a system-agnostic model independent of link parameters, and yet still achieve a similar or better performance at a lower complexity as compared with prior-art methods. Systems, methods, and structures according to aspects of the present disclosure include a data-driven model using the neural network (NN) to predict received signal nonlinearity without prior knowledge of the link parameters. Operationally, the NN is provided with intra-channel cross-phase modulation (IXPM) and intra-channel four-wave mixing (IFWM) triplets that advantageously provide a more direct pathway to underlying nonlinear interactions.

Abstract: An unrepeatered transmission system includes a receiver coupled to a receive span; a transmitter coupled to the receive span; and a plurality of cascaded amplifiers in the receive span with dedicated fiber cores to supply one or more optical pumps from the receiver to each amplifier, wherein the plurality of cascaded amplifiers increase system reach by increasing the length of a back span in an unrepeatered link.

Abstract: Systems and methods for transmission filtering are provided. A receiver includes an input coupled to a transmission line to receive distorted optical symbols. A distortion filter is coupled to the input to replace the distorted optical symbols with predicted symbols using a trained neural network. A decoder is coupled to the distortion filter to decode the predicted symbols.

Abstract: An optical communication substrate includes a plurality of cores to communicate optical signals; a rectangular input delivering a pump laser, and a shaped portion to combine the optical signals and the pump laser into a ring geometry at an output.

Abstract: Aspects of the present disclosure describe systems, methods and structures for optical fiber nonlinearity compensation using neural networks that advantageously employ machine learning (ML) algorithms for nonlinearity compensation (NLC) that advantageously provide a system-agnostic model independent of link parameters, and yet still achieve a similar or better performance at a lower complexity as compared with prior-art methods. Systems, methods, and structures according to aspects of the present disclosure include a data-driven model using the neural network (NN) to predict received signal nonlinearity without prior knowledge of the link parameters. Operationally, the NN is provided with intra-channel cross-phase modulation (IXPM) and intra-channel four-wave mixing (IFWM) triplets that advantageously provide a more direct pathway to underlying nonlinear interactions.

Abstract: Systems and methods for optical data transport, including controlling data transport across an optical transmission medium by generating two-dimensional (2D) distribution matchers (DMs) based on probabilistic fold shaping (PFS) and arbitrary probabilistic shaping (APS). The 2D PFS-based DM is can encode any N-fold rotationally symmetrical Quadrature Amplitude Modulation (QAM) format by applying the 2D PFS-based DM only to symbols in one quadrant based on a target entropy. A fold index yield uniform distribution is determined, and is utilized to carry generated uniform distributed parity check bits across the optical transmission medium. The 2D APS-based DM can encode any arbitrary modulation formats by encoding uniform binary data to generate non-uniform target symbols, and generating a probability distribution for the target symbols by indirectly applying the 2D APS-based DM based on a target probability distribution and a detected code rate of generated FEC code.

Abstract: A system and method are provided for distributed acoustic sensing in a multimode optical fiber. The system includes a transmitter for simultaneously propagating a sequence of M light pulses through the multimode optical fiber using a spatial mode selected from a set of N spatial modes provided by a spatial mode selector for the transmitter that is coupled to an input to the multimode optical fiber, with M and N being respective integers greater than one. The system further includes a receiver for receiving the sequence of M light pulses at an output of the multimode optical fiber and detecting an environmental perturbation in the multimode optical fiber based on an evaluation of a propagation of the sequence of M light pulses through the multimode optical fiber.

Abstract: Aspects of the present disclosure describe fiber nonlinearity induced transmission penalties are reduced both in fibers with large polarization-mode dispersion, and in coupled-core multicore fibers (CC-MCF). In the case of coupled multi-core fibers, the requirement for modal delay is less.

Abstract: Aspects of the present disclosure describe a method for digital coherent transmission systems that advantageously provides low-complexity, single-step nonlinearity compensation based on artificial intelligence (AI) implemented in a deep neuron network (DNN).

Abstract: Aspects of the present disclosure describe methods of generating an optimized set of constellation symbols for an optical transmission network wherein the optimized constellation is based on GMI cost and considers both fiber nonlinearity and linear transmission noise.

Abstract: Systems and methods for data transport in optical communications systems, including a transmitter for encoding a received information sequence by constructing an outer and inner quasi cyclic-low-density parity check (QC-LDPC) code. The encoding includes dividing the received information sequence into a plurality of messages of equal length, encoding each of the messages into a codeword to generate a plurality of outer codewords, cascading the plurality of outer codewords to generate a bit sequence, and executing inner encoding to encode each of the plurality of outer codewords into codewords in QC-LDPC inner code. A receiver decodes a received data stream based on the QC-LDPC inner code using two-phase decoding including iteratively performing at least one of inner/outer and outer/inner decoding until a threshold condition is reached.

Abstract: Aspects of the present disclosure describe systems, methods, and structures for high speed frequency hopping distributed acoustic sensing using an acousto-optic modulated (AOM), gated re-circulating loop and a frequency shifted receiver local oscillator. Using the re-circulating loop controlled by the AOM to generate frequency-hopping pulse(s) increases DAS acoustic bandwidth overcomes infirmities exhibited in the art that generate multiple frequency patterns that are not suitable for long-distance DAS. Additionally, by employing frequency shifted local oscillator (LO) with asymmetric in band detection, bandwidth requirements are reduced by one half.

Abstract: Aspects of the present disclosure describe systems, methods, and structures for providing C-band and L-band transmission exhibiting increased power efficiency by diverting a portion of C-band optical energy to an input of L-band optical amplifiers (C-seeding) while optionally employing circulators to eliminate the need for optical isolators.

Abstract: Aspects of the present disclosure describe fiber nonlinearity induced transmission penalties are reduced both in fibers with large polarization-mode dispersion, and in coupled-core multicore fibers (CC-MCF). In the case of coupled multi-core fibers, the requirement for modal delay is less.