公开(公告)号：US20180262293A1

公开(公告)日：2018-09-13

申请号：US15912781

申请日：2018-03-06

Applicant: NEC LABORATORIES AMERICA, INC.

Inventor： Ezra Ip ,  Yue-Kai Huang ,  Shuji Murakami ,  Philip Ji

IPC: H04J14/02

CPC classification number: H04J14/0215 ,  H04J14/0204 ,  H04J14/0205 ,  H04J14/0212 ,  H04J14/023 ,  H04J14/0282 ,  H04J14/0295 ,  H04Q11/0005 ,  H04Q2011/0016

Abstract: Aspects of the present disclosure describe systems, methods, and structures for passive optical add/drop multiplexing (POADM) architectures that remove the prior art requirement of an optical amplifier (i.e., repeater-less) at the POADM nodes.

公开(公告)号：US09813157B2

公开(公告)日：2017-11-07

申请号：US15062179

申请日：2016-03-06

Applicant: NEC Laboratories America, Inc.

Inventor： Shaoling Zhang ,  Fatih Yaman ,  Yue-Kai Huang ,  Ezra Ip ,  Yoshihisa Inada

IPC: H04B10/00 ,  H04B10/2581 ,  H04L25/03 ,  H04B10/2543 ,  H04B10/69

CPC classification number: H04B10/2581 ,  H04B10/2543 ,  H04B10/6971 ,  H04L25/03885

Abstract: Aspects of the present disclosure are directed to the mitigation of multi-path interference from quasi-single-mode fiber using hybrid span configuration and digital signal processing wherein a hybrid span of quasi-single mode fibers and single-mode fibers are used to configure the hybrid span. Additional aspects are directed to introducing a low-baud rate sub-banding signal to reduce the number of DD-LMS taps required when compensating the multi-path interference as the low-baud rate signal requires fewer taps to cover a given range of MPI as compared to a high-baud rate signal. Finally further aspects are directed to an ALMS equalizer which further reduces the number of equalizer taps by shifting its center tap towards the right if higher-order modes transmit slower than a fundamental mode, otherwise the center tap is shifted to the left.

公开(公告)号：US20170211970A1

公开(公告)日：2017-07-27

申请号：US15385972

申请日：2016-12-21

Applicant: NEC Laboratories America, Inc.

Inventor： Giovanni Milione ,  Philip Nan Ji ,  Ezra Ip ,  Ting Wang

IPC: G01H9/00

CPC classification number: G01H9/004

Abstract: A system to perform distributed acoustic sensing (DAS) in an environment with acoustic vibrations present includes at least an optical fiber positioned in said environment, wherein the optical fiber comprises N spatial channels and N laser pulses are launched into the N spatial channels of the optical fiber and propagate over a fiber length; and one or more sensors to measure N signals of acoustic vibration amplitude and frequency from each of N spatial channels, wherein the N signals are digitally added for spatial averaging and applied to determine DAS.

公开(公告)号：US20140063592A1

公开(公告)日：2014-03-06

申请号：US14019015

申请日：2013-09-05

Applicant: NEC LABORATORIES AMERICA, INC.

Inventor： Ezra Ip

IPC: H01S3/13

CPC classification number: H01S3/1302 ,  H01S3/0078 ,  H01S3/0085 ,  H01S3/06729 ,  H01S3/06754 ,  H01S3/0804 ,  H01S3/094003 ,  H01S3/10015 ,  H01S3/1608 ,  H04B10/2581 ,  H04B10/293

Abstract: Disclosed herein are methods, structures and systems for few-mode fiber (FMF) transmission including an optical amplifier exhibiting modal gain control suitable for such transmission in which higher order modes are amplified. An exemplary evaluation system is described and results presented.

Abstract translation: 这里公开了用于多模光纤（FMF）传输的方法，结构和系统，其包括具有适用于其中放大高阶模的这种传输的模态增益控制的光放大器。 描述了一个示例性的评估系统并提出了结果。

公开(公告)号：US12287234B2

公开(公告)日：2025-04-29

申请号：US17964899

申请日：2022-10-12

Applicant: NEC Laboratories America, Inc.

Inventor： Yue-Kai Huang ,  Ezra Ip

IPC: G01H9/00

Abstract: Aspects of the present disclosure describe distributed fiber optic sensing (DFOS)/distributed acoustic sensing (DAS) systems, methods, and structures exhibiting a sensitivity enhancement via MIMO sampling and phase recombination.

公开(公告)号：US12055803B2

公开(公告)日：2024-08-06

申请号：US17316621

申请日：2021-05-10

Applicant: NEC Laboratories America, Inc.

Inventor： Ezra Ip ,  Yue-Kai Huang ,  Philip Ji ,  Shuji Murakami

IPC: G01M11/00 ,  G01H9/00 ,  G02F1/125 ,  G01D5/353 ,  H04B10/071

CPC classification number: G02F1/125 ,  G01H9/004 ,  G01D5/35361 ,  G01M11/00 ,  G01M11/3109 ,  G01N2201/0886 ,  H04B10/071

Abstract: Aspects of the present disclosure describe improved distributed acoustic sensing using dynamic range suppression of optical time domain reflectometry either by using a feedback loop comprising optical and electrical elements or using a nonlinear element in the electrical domain after coherent detection. When using a feedback loop, the amplitude of the periodic waveform of coherent OTDR can be inverted. This allows optical pre-compensation of the received optical signal before coherent detection with the goal of minimizing amplitude dynamic range. Alternatively, a nonlinear element in the electrical domain can reduce amplitude dynamic range before sampling by analog-to-digital converters (ADC).

公开(公告)号：US11733088B2

公开(公告)日：2023-08-22

申请号：US17548581

申请日：2021-12-12

Applicant: NEC Laboratories America, Inc.

Inventor： Junqiang Hu ,  Yue-Kai Huang ,  Ezra Ip

IPC: G01H9/00 ,  G01D5/353

CPC classification number: G01H9/004 ,  G01D5/35358

Abstract: A spatial averaging method for a coherent distributed acoustic sensing (DAS) system that employs differential beating and polarization combining of signals for two locations along a length of optical sensing fiber to determine phase change in-between every location along the length of the optical sensing fiber and a moving average using polarization combining output to reduce any Rayleigh fading before phase determination.

公开(公告)号：US11543287B2

公开(公告)日：2023-01-03

申请号：US17324089

申请日：2021-05-18

Applicant: NEC Laboratories America, Inc.

Inventor： Ezra Ip ,  Yue-Kai Huang

IPC: G01H9/00

Abstract: Systems, methods, and structures that provide distributed acoustic sensing using chirped optical pulses of selectable duration and bandwidth, at a frame rate limited by a round-trip propagation time of a fiber under test. Instead of processing a transmitted chirped pulse as a single sequence—our systems, methods, and structures employ a parallel fragmented multiband architecture, where each tributary correlates the received signal with a truncated chirped pulse to obtain the Rayleigh impulse response over its frequency band. By reducing the duration of the chirp processed by each tributary, spatial leakage is reduced at all the tributaries, thus even after combining all the interferometric products from all tributaries using a rotated vector sum, the resultant signal is much less impacted by spatial leakage than by using a conventional TGD-OFDR method.

公开(公告)号：US11159200B2

公开(公告)日：2021-10-26

申请号：US16258586

申请日：2019-01-26

Applicant: NEC Laboratories America, Inc.

Inventor： Yue-Kai Huang ,  Ezra Ip ,  Giovanni Milione ,  Fatih Yaman

IPC: H04B1/00 ,  H04B1/7136 ,  G01H9/00 ,  H04B1/715 ,  H04B1/7143 ,  H04B14/00 ,  H04B1/713

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.

公开(公告)号：US10763964B2

公开(公告)日：2020-09-01

申请号：US16454054

申请日：2019-06-27

Applicant: NEC Laboratories America, Inc.

Inventor： Yue-Kai Huang ,  Ezra Ip ,  Philip Nan Ji ,  Ming-Fang Huang

IPC: H04B10/00 ,  H04B10/2543 ,  H04B10/25 ,  H04J14/00

Abstract: Aspects of the present disclosure describe systems, methods and structures providing bidirectional optical fiber communication and sensing using the same fiber transmission band and bidirectional WDM fiber sharing such that communications channels and optical fiber sensing channel(s) coexist on the same fiber. As a result, nonlinear interaction between communications channels and interrogating pulse(s) of sensing are much reduced or eliminated.