公开(公告)号：US08982340B2

公开(公告)日：2015-03-17

申请号：US13947113

申请日：2013-07-22

Applicant: Ramot at Tel-Aviv University Ltd.

Inventor： Yair Peled ,  Moshe Tur

IPC: G01M11/00

CPC classification number: G01M11/3172 ,  G01M11/39

Abstract: A method for conducting fast Brillouin optical time domain analysis for dynamic sensing of optical fibers is provided herein. The method includes the following stages: injecting a pump pulse signal into a first end of an optical fiber and a probe signal into a second end of the optical fiber, wherein the probe and the pump pulse signals exhibit a frequency difference between them that is appropriate for an occurrence of a Brillouin effect; alternating the frequency of either the probe or the pulse signals, so as the alternated signal exhibits a series of signal sections, each signal section having a predefined common duration and a different frequency; measuring the Brillouin probe gain for each one of the alternating frequencies; and extracting physical properties of the optical fiber throughout its length at sample points associated with the sampled time and the frequencies, based on the measured Brillouin probe gain.

Abstract translation: 本文提供了一种用于进行光纤动态感测的快速布里渊光时域分析的方法。 该方法包括以下步骤：将泵浦脉冲信号注入到光纤的第一端并将探测信号注入光纤的第二端，其中探针和泵浦脉冲信号在它们之间表现出适当的频率差 发生布里渊效应; 交替的探针或脉冲信号的频率，以便交替的信号表现出一系列信号部分，每个信号部分具有预定的公共持续时间和不同的频率; 测量每个交变频率的布里渊探针增益; 并且基于所测量的布里渊探针增益，在与采样时间和频率相关联的采样点处，在整个长度上提取光纤的物理特性。

公开(公告)号：US10036686B2

公开(公告)日：2018-07-31

申请号：US15077264

申请日：2016-03-22

Applicant: Ramot at Tel-Aviv University Ltd.

Inventor： Moshe Tur ,  Ido Sovran ,  Avi Motil

IPC: G01N21/00 ,  G01M11/00

CPC classification number: G01M11/39 ,  G01M11/319

Abstract: A method and a system for ultimately fast frequency-scanning Brillouin optical time domain analysis are provided herein. The method may include: simultaneously launching two pairs each having a pulsed pump wave and a counter-propagating constant wave (CW) probe wave, into an optical fiber, wherein the pulsed pumps have orthogonal States of Polarization (SOPs), and wherein the two CW probe waves have a same SOP; scanning common pump-probe frequency difference, over a frequency range that encompasses a respective Brillouin Gain Spectrum (BGS) and current and expected spectral shifts of the BGS along the optical fiber; deriving, a local Brillouin Frequency Shift (BFS), in a distributed manner along the optical fiber, which is defined as the pump-probe frequency difference which maximizes the Brillouin gain on the BGS; and determining strain and/or temperature in a distributed manner along the optical fiber, based on the respective local BFS.

公开(公告)号：US09885619B2

公开(公告)日：2018-02-06

申请号：US15109644

申请日：2015-01-01

Applicant: Ramot at Tel-Aviv University Ltd.

Inventor： Moshe Tur ,  Avi Motil ,  Yair Peled ,  Or Danon

IPC: G01K11/32 ,  G01L1/24

CPC classification number: G01K11/32 ,  G01K2011/322 ,  G01L1/246

Abstract: A method of stimulated Brillouin scattering is proposed in which both slopes of the BGS spectrum are probed to achieve immunity to pump power variations. Suitably applied, the technique can maintain all the benefits of the known Slope-Assisted-BOTDA technique, while using the same setup but at the cost of halving the sampling speed. the method may include: obtaining a reference Brillouin gain spectrum (BGS) representative of steady state or average conditions in various locations of the optical fiber along its length; generating, based on the reference BGS, a probe wave being a complex waveform comprising a first and second set of waveforms, each set having waveforms tailored to match an opposite slope of the reference BGS, at the various locations; performing stimulated Brillouin scattering at the various locations by applying a pump pulse wave to the probe wave; and deducing the local Brillouin frequency shift (BFS) at the various locations.