Nec Corporation

Nec Laboratories America, Inc.

University of Central Florida Research Foundation Inc

Fatih Yaman

Shaoliang Zhang

Yoshihisa Inada

Yue-Kai Huang

Ting Wang

Takanori Inoue

Takaaki Ogata

Eduardo Rodriguez

Kohei Nakamura

Ezra Ip

Guifang Li

Yasuhiro Aoki

Hussam Batshon

Lei Xu

Eduardo F Mateo

Shinsuke Fujisawa

Giovanni Milione

Eduardo Mateo Rodriquez

Dayou Qian

Ryuji Aida

Xiaobo Xie

Likai Zhu

Inwoong Kim

Naoto Ishii

Junqiang Nochur Hu

Xin Chen

Emmanuel Le Taillandier De Gabory

Yoshinari Takigawa

Gilad Goldfarb

Neng Bai

Ryu Kurahashi

Yequn Zhang

Weiyang Mo

Xiaoxu Li

Ben Wu

Hassam Batshon

Zhen Qu

Ankith Vinayachandran

Takigawa Yoshinari

Wei Zhou

Shaoling Zhang

Cen Xia

Earthquake detection via fiber sensing is provided using using a supervisory path of submarine cables wherein the supervisory system/path of a submarine optical cable conveys portion(s) of an optical signal back to an origin location periodically—i.e., at every repeater location. Advantageously, since it is known where a returning signal is coming from, a resolution equivalent to an undersea span length may be determined—which is sufficient for wide area disturbances such as earthquakes. The returned signal is sufficiently strong such that the signal-to-noise ratio of a returned/received signal is not limited by the ASE noise of the amplifiers. The returned signal is much larger as compared to a normal distributed acoustic sensing (DAS) return signal since the return signal according to aspects of the present disclosure is directed backward via an optical coupler/reflector/circulator having a much larger coupling ratio as compared to normal Rayleigh back scattering utilized in DAS.

Fiber sensing using supervisory path of submarine cables

An optical communication system includes a first terminal device configured to receive first data, wherein the first terminal device is configured to generate an optical waveform based on the received first data. The optical system further includes an optical communication path configured to receive the optical waveform from the first terminal device. The optical system further includes a second terminal device configured to receive the optical waveform from the optical communication path, wherein the second terminal device is configured to output second data based on the optical waveform. At least one of the first terminal device or the second terminal device includes a nonlinear waveform distortion compensation device. The nonlinear waveform compensation device is configured to correct nonlinear waveform distortion resulting from the optical waveform propagating along the optical communication path, and the nonlinear waveform compensation device includes at least one recursive intermediate layer.

Method of equalizing waveform distortion, terminal device, and optical communication system

Aspects of the present disclosure are directed to systems, methods, and structures providing for the accurate measurement of guided acoustic-wave Brillouin scattering in optical fiber transmission systems and facilities.

Accurate measurement for guided acoustic-wave Brillouin scattering

Aspects of the present disclosure are directed to laser interferometric systems, methods, and structures exhibiting superior laser phase noise tolerance particularly in seismic detection applications wherein laser requirements are advantageously relaxed by employing a novel configuration wherein the same laser which generates an outgoing signal is coherently detected using the same laser as local oscillator and fiber turnarounds are employed that result in the cancellation and/or mitigation of undesired mechanical vibration.

Laser noise reduction for laser interferometry

Aspects of the present disclosure describe estimating/measuring core-cladding concentricity error in optical fibers. In sharp contrast to the prior art, our inventive method is based on measuring a seemingly unrelated property of fibers called guided acoustic wave Brillouin scattering (GAWBS). As we shall show and describe, by analyzing this GAWBS property we advantageously determine what level of CCCE is exhibited by the optical fiber.

Estimating core-cladding concentricity error in optical fibers using guided acoustic-wave Brillouin scattering

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).

Repeater design for distributed acoustic sensing on multispan fiber links

Aspects of the present disclosure describe systems, methods. and structures directed to an integrated 3-way branching unit switch module suitable for undersea application.

Integrated 3-way branching unit switch module having small footprint

Aspects of the present disclosure describe methods for reducing guided acoustic wave Brillouin (GAWBS) noise in an optical fiber that may be included in an optical communications system by reducing the polarization diffusion length of the fiber by increasing the birefringence of the optical fiber, the increased birefringence of the optical fiber being increased with respect to its average magnitude. Additionally, the polarization diffusion length is reduced by reducing the coherence length of birefringence of the optical fiber.

Method for reducing GAWBS noise by reducing polarization diffusion length

Aspects of the present disclosure describe a three-way branching unit switch module having a small footprint suitable for application in an undersea application.

Three-way branching unit switch module having small footprint

Aspects of the present disclosure describe a method for estimating mode field distribution in optical fibers from guided acoustic-wave Brillouin scattering wherein light for which the optical mode-field distribution is determined remains in the optical fibers and the distribution is made for light inside the fiber, and not at a fiber/air interface or other perturbation points to the fiber resulting in a more accurate representation of the optical mode-field distribution in the fiber. Since light is always in the fiber during the determination, no complicated fiber preparation steps or procedures are required and the mode-field distribution is determined as an average distribution along the length of the fiber under test.

Estimating mode field distribution in optical fibers from guided acoustic wave brillouin scattering

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.

Constant amplitude coded DFOS using out-of-band signaling

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).

Single-step nonlinearity compensation using artificial intelligence for digital coherent transmission systems

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.

High speed frequency hopping DAS interrogation using AOM-gated re-circulating loop and frequency-shifted receiver LO

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.

Multicore fiber amplifier with high power efficiency

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.

Optical fiber nonlinearity compensation using neural networks

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Monmouth Junction, NJ, United States of America

Fatih Yaman