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1.发明授权Distributed sensor and method using coherence multiplexing of fiber-optic interferometric sensors 失效分布式传感器和使用光纤干涉传感器相干多路复用的方法
公开(公告)号：US4699513A
公开(公告)日：1987-10-13
申请号：US738678
申请日：1985-05-28
申请人： Janet L. Brooks , Moshe Tur , Robert C. Youngquist , Byoung Y. Kim , Robert H. Wentworth , Herbert J. Shaw , Kjell Blotekjaer
发明人： Janet L. Brooks , Moshe Tur , Robert C. Youngquist , Byoung Y. Kim , Robert H. Wentworth , Herbert J. Shaw , Kjell Blotekjaer
IPC分类号： G01D21/00 , G01D5/26 , G01D5/353 , G01H7/00 , G01H9/00 , G01K11/00 , G01L1/00 , G01N21/00 , G01N21/17 , G02B6/00 , G02B6/14 , G02B6/28 , G08C15/00 , H04J14/00 , G01B9/02
CPC分类号： G01D5/35383 , G02B6/14 , G02B6/2821 , G02B6/2826 , G02B6/283 , G02B6/2843 , G02B6/2861 , H04J14/002
摘要： A distributed sensor system including an optical source having a short coherence length for optionally continuously monitoring each sensor in the system. In one preferred embodiment, an array of fiber-optic sensors are organized in a ladder configuration, with the sensors positioned in spaced relation and defining the rungs of the ladder. Light transmitted through the sensors is multiplexed onto a return arm of the ladder, with sensor spacing being such that interference between light from different sensors is prevented. The multiplexed signals are received by an optical fiber receiver which couples the multiplexed light with an interfering optical reference signal to produce a phase difference signal representing conditions influencing selected sensors. Embodiments are disclosed for use of either pulsed or continuous wave light sources. In another preferred embodiment, the sensors comprise a plurality of interferometers connected in series configuration by a common optical fiber, which provides multiplexed output signals from the sensors to another plurality of interferometers comprising receivers. Functional equivalents of the series configuration provide sensors and receivers comprising birefringent or two-mode fiber. The optical path length differences between each pair of sensor arms are selected to prevent interference between the multiplexed sensor output signals from the various sensors. The optical path lengths through the sensors and receivers are structured so that each receiver produces a phase difference signal relating to conditions affecting light transmission through a specific sensor. A phase and amplitude modulation technique is disclosed for providing heterodyned output signals from the distributed sensor system.
摘要翻译： 一种分布式传感器系统，包括具有短相干长度的光源，用于可选地连续监测系统中的每个传感器。 在一个优选实施例中，光纤传感器阵列以梯形结构组织，传感器以间隔关系定位并限定梯子的梯级。 通过传感器传输的光被多路复用到梯子的返回臂上，传感器间隔使得防止来自不同传感器的光之间的干扰。 复用的信号由光纤接收器接收，光纤接收器将复用的光与干涉光参考信号耦合，以产生表示影响所选传感器的条件的相位差信号。 公开了使用脉冲或连续波光源的实施例。 在另一个优选实施例中，传感器包括通过公共光纤串联配置的多个干涉仪，其将来自传感器的多路复用输出信号提供给包括接收器的另外多个干涉仪。 串联配置的功能等同物提供包括双折射或双模光纤的传感器和接收器。 选择每对传感器臂之间的光程长度差以防止来自各种传感器的多路传感器输出信号之间的干扰。 通过传感器和接收器的光路长度被构造成使得每个接收器产生与影响通过特定传感器的光透射的条件相关的相位差信号。 公开了一种用于从分布式传感器系统提供外差输出信号的相位和幅度调制技术。
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公开(公告)号：US4770535A
公开(公告)日：1988-09-13
申请号：US877296
申请日：1986-06-23
CPC分类号： G01D5/35383
摘要： A distributed sensor system using pulsed optical signals optionally produced by a short coherence length source to provide a phase difference output signal representative of conditions affecting a selected sensor. In one preferred embodiment, an array of fiber-optic sensors are organized in a ladder configuration, with the sensors positioned in spaced relation and defining the rungs of the ladder. Light pulses transmitted through the sensors are multiplexed onto a return arm of the ladder. The multiplexed signals are received by an optical fiber compensating interferometer which coherently couples portions of adjacent multiplexed light signals to produce a phase difference signal representing conditions influencing selected sensors. In other preferred embodiments, the system is configured to define a plurality of adjacent Mach-Zehnder interferometers which provide output signal pairs which coherently couple to yield a phase difference signal directly representing the environmental effects on a particular sensor. Functional equivalents of the Mach-Zehnder interferometer configurations comprise configurations including adjacent Michelson interferometers. A phase and amplitude modulation technique is disclosed for providing heterodyned output signals from the distributed sensor system.
摘要翻译： 使用脉冲光信号的分布式传感器系统，其可选地由短相干长度源产生，以提供表示影响所选传感器的条件的相位差输出信号。 在一个优选实施例中，光纤传感器阵列以梯形结构组织，传感器以间隔关系定位并限定梯子的梯级。 通过传感器传输的光脉冲被复用到梯子的返回臂上。 复用的信号由光纤补偿干涉仪接收，该干涉仪相干地耦合相邻复用光信号的部分，以产生表示影响所选传感器的条件的相位差信号。 在其它优选实施例中，该系统被配置为限定多个相邻的马赫 - 曾德尔干涉仪，其提供相干耦合以产生直接表示对特定传感器的环境影响的相位差信号的输出信号对。 Mach-Zehnder干涉仪配置的功能等同物包括相邻的迈克尔逊干涉仪。 公开了一种用于从分布式传感器系统提供外差输出信号的相位和幅度调制技术。
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3.发明授权System and method for accurate loop length determination in fiber-optic sensors and signal processors 失效光纤传感器和信号处理器的精确环路长度确定的系统和方法
公开(公告)号：US4768880A
公开(公告)日：1988-09-06
申请号：US877321
申请日：1986-06-23
申请人： Moshe Tur , Byoung Y. Kim , Janet L. Brooks , Herbert J. Shaw
发明人： Moshe Tur , Byoung Y. Kim , Janet L. Brooks , Herbert J. Shaw
CPC分类号： G01D5/35303
摘要： A technique and system for accurate determination of differential propagation delays in fiber-optic circuits. The method includes providing a sinusoidally modulated optical signal to each of two waveguides defining optical paths. The optical signals received from the optical paths are combined to form a reference output signal which has a null waveform whenever the propagation delay between the optical signals contains an odd number of half periods of the optical signal waveforms. The difference in the sinusoidal modulation frequency producing a first and second null or constant waveform in the reference signal is determined. This difference value between adjacent frequencies forming the null or constant waveforms comprises the inverse of the difference of signal propagation delay in the two optical paths. Accuracy is improved by measuring the sinusoidal modulation frequencies corresponding to first and second waveforms which are not formed by adjacent frequencies. The difference between those nonadjacent frequencies is divided by the difference in the reference waveform orders of the null reference waveforms to obtain the inverse of the differential propagation delay. Further accuracy is achieved by measuring at least one of the waveform nulls at a high waveform order. Still further accuracy is achieved by monitoring the reference waveforms on a network analyzer and using a frequency synthesizer to more precisely match and identify the modulation frequencies corresponding to the null reference signal waveforms. A system is disclosed for implementing this technique optionally using optical sources having a short coherence length. Mathematical relationships are disclosed for use with measured values in obtaining further improved accuracy.
摘要翻译： 一种用于精确确定光纤电路差分传播延迟的技术和系统。 该方法包括向定义光路的两个波导中的每一个提供正弦调制光信号。 每当光信号中的传播延迟包含光信号波形的奇数个半周期时，从光路接收的光信号被组合以形成具有零波形的参考输出信号。 确定在参考信号中产生第一和第二无效或恒定波形的正弦调制频率的差异。 形成零波形或恒定波形的相邻频率之间的差值包括两个光路中的信号传播延迟差的倒数。 通过测量对应于不由相邻频率形成的第一和第二波形的正弦调制频率来提高精度。 这些不相邻频率之间的差异除以空参考波形的参考波形次数的差异，以获得差分传播延迟的倒数。 通过以高波形顺序测量至少一个波形零点来实现进一步的精度。 通过监视网络分析仪上的参考波形并使用频率合成器更精确地匹配和识别与空参考信号波形相对应的调制频率，可以进一步提高精度。 公开了一种用于实现该技术的系统，其可选地使用具有短相干长度的光源。 公开了与测量值一起使用的数学关系，以获得进一步提高的准确度。
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4.发明授权Fiber optic modal coupler, interferometer and method of coupling spatial modes using same 失效光纤模态耦合器，干涉仪和使用它们耦合空间模式的方法
公开(公告)号：US4768851A
公开(公告)日：1988-09-06
申请号：US884871
申请日：1986-07-09
CPC分类号： G02B6/29352 , G02B6/2726 , G02B6/2821 , G02F1/0134 , Y10S359/90
摘要： A modal coupler, for coupling between first and second order modes of an optical fiber, comprises a single continuous strand of optical fiber, and a device for applying stress to the optical fiber at spaced intervals along the fiber. The stress deforms the fiber and abruptly changes the fiber geometry at the beginning and end of each stressed region. The change in fiber geometry causes coupling of light from the fundamental mode to the second order mode. The coupler, under certain conditions, exhibits polarization dependence, and thus, it may be utilized as a fiber optic polarizer. In addition, the device couples coherently, and may be used in interferometric systems.
摘要翻译： 用于在光纤的一阶和二阶模之间耦合的模式耦合器包括单个连续的光纤链，以及用于沿光纤以间隔间隔向光纤施加应力的装置。 应力使纤维变形，并突然改变每个应力区域的开始和结束处的纤维几何形状。 光纤几何形状的改变导致从基模到二阶模的耦合。 在一定条件下，耦合器具有偏振相关性，因此可用作光纤偏振器。 此外，该装置相干耦合，并可用于干涉系统。
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5.发明授权
公开(公告)号：US4697926A
公开(公告)日：1987-10-06
申请号：US699855
申请日：1985-02-08
申请人： Robert C. Youngquist , Janet L. Brooks , Kenneth A. Fesler , Cassius C. Cutler , Herbert J. Shaw
发明人： Robert C. Youngquist , Janet L. Brooks , Kenneth A. Fesler , Cassius C. Cutler , Herbert J. Shaw
CPC分类号： G01D5/35383
摘要： A distributed sensor system including an optical source having a short coherence length for optionally continuously monitoring each sensor in the system. In one preferred embodiment, an array of fiber-optic sensors are organized in a ladder configuration, with the sensors positioned in spaced relation and defining the rungs of the ladder. Light transmitted through the sensors is multiplexed onto a return arm of the ladder, with sensor spacing being such that interference between light from different sensors is prevented. The multiplexed signals are received by an optical fiber receiver which couples the multiplexed light with an interfering optical reference signal to produce a phase difference signal representing conditions influencing selected sensors. Embodiments are disclosed for use of either pulsed or continuous wave light sources. In another preferred embodiment, the sensors comprise a plurality of Mach-Zehnder interferometers connected in series configuration by a common optical fiber, which provides multiplexed output signals from the sensors to a plurality of Mach-Zehnder interferometers comprising receivers. The optical path length differences between the arms of each of the sensors are selected to prevent interference between the multiplexed sensor output signals from various sensors. The optical path lengths through the sensors and receivers are structured so that each receiver produces a phase difference signal relating to conditions affecting light transmission through a specific sensor. A phase and amplitude modulation technique is disclosed for providing heterodyned output signals from the distributed sensor system.
摘要翻译： 一种分布式传感器系统，包括具有短相干长度的光源，用于可选地连续监测系统中的每个传感器。 在一个优选实施例中，光纤传感器阵列以梯形结构组织，传感器以间隔关系定位并限定梯子的梯级。 通过传感器传输的光被多路复用到梯子的返回臂上，传感器间隔使得防止来自不同传感器的光之间的干扰。 复用的信号由光纤接收器接收，光纤接收器将复用的光与干涉光参考信号耦合，以产生表示影响所选传感器的条件的相位差信号。 公开了使用脉冲或连续波光源的实施例。 在另一个优选实施例中，传感器包括通过公共光纤串联配置的多个马赫 - 曾德干涉仪，其将来自传感器的多路复用输出信号提供给包括接收器的多个马赫 - 曾德干涉仪。 选择每个传感器的臂之间的光程长度差以防止来自各种传感器的多路传感器输出信号之间的干扰。 通过传感器和接收器的光路长度被构造成使得每个接收器产生与影响通过特定传感器的光透射的条件相关的相位差信号。 公开了一种用于从分布式传感器系统提供外差输出信号的相位和幅度调制技术。
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6.发明授权Birefringent fiber narrowband polarization coupler and method of coupling using same 失效双折射光纤窄带偏振耦合器及其耦合方法
公开(公告)号：US4801189A
公开(公告)日：1989-01-31
申请号：US161375
申请日：1988-02-22
CPC分类号： G02B6/274 , G02B6/2766 , G02B6/2821 , G02F1/0134 , Y10S359/90
摘要： There is disclosed herein a fiber optic directional coupler for coupling light between two polarization modes. A highly birefringent fiber optic waveguide is positioned on a flat polished surface with either of the principal axes of birefringence oriented at an angle, preferably 45.degree., to the vertical. A ridged block is then pressed down on the fiber. The ridges of the block have longitudinal axes transverse to the longitudinal axis of the fiber. The width of the ridge faces is one-half beat length, and the spacing between the ridges in also one-half beat length. The stressed regions caused by the ridges cause coupling of light traveling in one polarization mode into the other polarization mode by abrupt shifting of the axes of birefringence at the boundaries of the stressed regions.
摘要翻译： 这里公开了用于在两个偏振模式之间耦合光的光纤定向耦合器。 高度双折射的光纤波导位于平坦抛光表面上，双折射的主轴线与垂直方向成一定角度，最好是45°。 然后将一个脊状块压在纤维上。 块的脊具有横向于纤维的纵向轴线的纵向轴线。 脊面的宽度为半节拍长度，脊之间的间距也为半节拍长度。 由脊部引起的应力区域通过在应力区域的边界处的双折射轴的突然移位而导致以一种偏振模式行进的光耦合到另一种偏振模式。
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7.发明授权Single mode fiber optic single sideband modulator and method of frequency shifting using same 失效单模光纤单边带调制器和使用相同方式进行频移
公开(公告)号：US4792207A
公开(公告)日：1988-12-20
申请号：US50762
申请日：1987-05-15
CPC分类号： G02F1/0134 , G02B6/2821 , G02F1/125 , Y10S359/90
摘要： A fiber optic frequency shifter comprising two waveguides having different indices of refraction. In some embodiments the waveguides are two modes of propagation in one fiber. Plural distributed coupling ridges, or electrodes mounted adjacent piezoelectric materials, are independently driven to apply sinusoidally varying forces to the fiber. In some embodiments, the phase relationship of the driving signals for the electrodes or ridges is such that a travelling acoustic wave is launched in the fiber. In other embodiments, regions of stress in the fiber are created by an acoustic wave coupled into the fiber from a transducer coupled to an acoustic medium surrounding the fiber. The input carrier light is shifted in frequency by the frequency of the acoustic wave.
摘要翻译： 一种光纤移频器，包括具有不同折射率的两个波导。 在一些实施例中，波导是在一个光纤中的两种传播模式。 多个分布耦合脊或邻近压电材料安装的电极被独立地驱动以向光纤施加正弦变化的力。 在一些实施例中，用于电极或脊的驱动信号的相位关系使得行进声波在光纤中发射。 在其他实施例中，光纤中的应力区域是由耦合到围绕光纤的声学介质的传感器耦合到光纤中的声波产生的。 输入载波的频率以声波的频率移动。
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公开(公告)号：US4778237A
公开(公告)日：1988-10-18
申请号：US618032
申请日：1984-06-07
CPC分类号： G02B6/266 , G02B6/2821 , G02B6/2826 , G02B6/2861 , G02F1/3523
摘要： A fiber optic saturable absorber for processing optical signals comprises an optical fiber from which a portion of the cladding is removed to form a facing surface. A light-absorbing substance having non-linear light-absorbing characteristics is applied to the facing surface such that a portion of the optical signal energy is transferred from the fiber to the substance where it is absorbed. The device selectively attenuates the optical signal and noise, and can be used to reduce pulse waveform distortion caused by pulse broadening and by amplification of system noise.
摘要翻译： 用于处理光信号的光纤可饱和吸收器包括光纤，其中去除了包层的一部分以形成面对表面。 具有非线性光吸收特性的光吸收物质被施加到相对表面，使得光信号能量的一部分从纤维转移到被吸收的物质。 该器件选择性地衰减光信号和噪声，可用于减少由脉冲展宽和系统噪声放大引起的脉冲波形失真。
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公开(公告)号：US4684215A
公开(公告)日：1987-08-04
申请号：US556636
申请日：1983-11-30
IPC分类号： G02B6/00 , G02B6/14 , G02B6/28 , G02F1/01 , G02F1/125 , G02F2/02 , G02B6/02 , G02B5/30 , G02F1/11
CPC分类号： G02B6/2821 , G02F1/0134
摘要： A fiber optic frequency shifter comprising two waveguides having different indices of refraction. In some embodiments the waveguides are two modes of propagation in one fiber. Plural distributed coupling ridges, or electrodes mounted adjacent piezoelectric materials, are independently driven to apply sinusoidally varying forces to the fiber. In some embodiments, the phase relationship of the driving signals for the electrodes or ridges is such that a travelling acoustic wave is launched in the fiber. In other embodiments, regions of stress in the fiber are created by an acoustic wave coupled into the fiber from a transducer coupled to an acoustic medium surrounding the fiber. The input carrier light is shifted in frequency by the frequency of the acoustic wave.
摘要翻译： 一种光纤移频器，包括具有不同折射率的两个波导。 在一些实施例中，波导是在一个光纤中的两种传播模式。 多个分布耦合脊或邻近压电材料安装的电极被独立地驱动以向光纤施加正弦变化的力。 在一些实施例中，用于电极或脊的驱动信号的相位关系使得行进声波在光纤中发射。 在其他实施例中，光纤中的应力区域是由耦合到围绕光纤的声学介质的传感器耦合到光纤中的声波产生的。 输入载波的频率以声波的频率移动。
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公开(公告)号：US4832437A
公开(公告)日：1989-05-23
申请号：US48142
申请日：1987-05-11
CPC分类号： G02B6/14 , G02B6/2821 , G02F1/0134
摘要： An optical fiber is subjected to a series of traveling flexural waves propagating along a length of the fiber. At least a portion of an optical signal propagating within the optical fiber in a first propagation mode is coupled to a second propagation mode. The optical signal in the second propagation mode has a frequency which is equal to either the sum of or the difference between the frequency of the optical signal in the first propagation mode and the frequency of the traveling flexural waves. The frequency of the optical signal in the second propagation mode is shifted upward or downward from the frequency of the optical signal in the first propagation mode as determined by the direction of propagation of the first optical signal with respect to the direction of propagation of the traveling flexural waves, and as also determined by whether the phase propagation velocity of the optical signal in the first propagation mode is greater than or less than the propagation velocity of the optical signal in the second propagation mode.
摘要翻译： 光纤经受沿纤维长度传播的一系列行进弯曲波。 以第一传播模式在光纤内传播的光信号的至少一部分耦合到第二传播模式。 第二传播模式中的光信号具有等于第一传播模式中的光信号的频率与行进的弯曲波的频率的和之和的频率的频率。 第二传播模式中的光信号的频率从第一传播模式中的光信号的频率向上或向下偏移，由第一光信号相对于传播的传播方向的传播方向确定 弯曲波，并且还根据第一传播模式中的光信号的相位传播速度是否大于或小于第二传播模式中的光信号的传播速度来确定。
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