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公开(公告)号：US4895421A
公开(公告)日：1990-01-23
申请号：US189050
申请日：1988-05-02
申请人： Byoung Y. Kim , Hee G. Park , Herbert J. Shaw
发明人： Byoung Y. Kim , Hee G. Park , Herbert J. Shaw
IPC分类号： G02B6/14 , G02B6/34 , G02F1/35 , H04B10/2569
CPC分类号： H04B10/2569 , G02B6/02047 , G02B6/14 , G02B6/4215 , G02F1/3515 , G02B6/2931 , G02B6/29311 , G02B6/29344 , Y10S359/90
摘要： An optical mode coupling apparatus includes an optical waveguide in which an optical signal at a signal wavelength propagates in a first spatial propagation mode and a second spatial propagation mode of the waveguide. The optical signal propagating in the waveguide has a beat length. The coupling apparatus includes a source of perturbational light signal at a perturbational wavelength that propagates in the waveguide in the first spatial propagation mode. The perturbational signal has a sufficient intensity distribution in the waveguide that it causes a perturbation of the effective refractive index of the first spatial propagation mode of the waveguide in accordance with the optical Kerr effect. The perturbation of the effective refractive index of the first spatial propagation mode of the optical waveguide causes a change in the differential phase delay in the optical signal propagating in the first and second spatial propagation modes. The change in the differential phase delay is detected as a change in the intensity distribution between two lobes of the optical intensity distribution pattern of an output signal. The perturbational light signal can be selectively enabled and disabled to selectively change the intensity distribution in the two lobes of the optical intensity distribution pattern.
摘要翻译： 光模耦合装置包括光波导，其中信号波长的光信号以波导的第一空间传播模式和第二空间传播模式传播。 在波导中传播的光信号具有拍子长度。 耦合装置包括在第一空间传播模式下在波导中传播的扰动波长的扰动光信号源。 扰动信号在波导中具有足够的强度分布，其根据光学克尔效应引起波导的第一空间传播模式的有效折射率的扰动。 光波导的第一空间传播模式的有效折射率的扰动导致在第一和第二空间传播模式中传播的光信号中的差分相位延迟的变化。 差分相位延迟的变化被检测为输出信号的光强度分布图案的两个波瓣之间的强度分布的变化。 扰动光信号可以选择性地启用和禁用，以选择性地改变光强度分布图案的两个波瓣中的强度分布。
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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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公开(公告)号：US5177562A
公开(公告)日：1993-01-05
申请号：US880290
申请日：1992-05-04
CPC分类号： G01B9/0209 , G01C19/721 , H01S3/06795 , G01B2290/70
摘要： The present invention discloses a thermally stable rare-earth doped fiber source comprising an active medium such as Erbium or Neodymium. The thermal stability of the mean wavelength of such a source is determined by three contributions as expressed by the following differential equation: ##EQU1## The first term is the intrinsic temperature dependence of the active medium, the second term is the pump power dependence and the third term is a contribution that arises from the dependence of the emission wavelength on the pump wavelength. The method of the present invention minimizes the temperature dependence on the mean wavelength by using the above equation and optimizing the values of the pump power and the pump wavelength so that the three contributions in the governing equation cancel each other.
摘要翻译： 本发明公开了一种包含铒或钕等活性介质的热稳定性稀土掺杂光纤源。 这种源的平均波长的热稳定性由以下微分方程表示的三个贡献确定：第一项是活性介质的固有温度依赖性，第二项是 泵浦功率依赖性，第三项是由发射波长对泵浦波长的依赖性引起的贡献。 本发明的方法通过使用上述方程使对平均波长的温度依赖性最小化，并优化泵功率和泵浦波长的值，使得控制方程中的三个贡献相互抵消。
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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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5.发明授权Technique of reducing the Kerr effect and extending the dynamic range in a Brillouin fiber optic gyroscope 失效降低克尔效应并延长布里渊光纤陀螺仪动态范围的技术
公开(公告)号：US5351252A
公开(公告)日：1994-09-27
申请号：US23672
申请日：1993-02-26
CPC分类号： H01S3/302 , G01C19/727
摘要： A Brillouin fiber optic gyroscope having a feedback system which monitors the difference between counterpropagating Brillouin intensities and utilizes this difference in the form of a correction signal to control one of the circulating pump intensities so as to equalize the circulating pump intensities. The Brillouin fiber optic gyroscope further includes a second feedback system which detects electrical signals proportional to the phase-modulated, counterpropagating intensities in the gyroscope, and utilizes a combination of the electrical signals as an error signal to stabilize the resonant cavity at a length substantially equal to a length midway between the resonant lengths of the counterpropagating pump signals. The Brillouin fiber optic gyroscope of the present invention also provides a dynamic range of the gyroscope rotation rate that is twice the dynamic range of existing gyroscopes.
摘要翻译： 布里渊光纤陀螺仪具有反馈系统，该反馈系统监测反向传播布里渊强度之间的差异，并以校正信号的形式利用该差异来控制循环泵浦强度之一，以便均衡循环泵浦强度。 布里渊光纤陀螺仪还包括第二反馈系统，其检测与陀螺仪中相位调制的反向传播强度成比例的电信号，并且利用电信号的组合作为误差信号，以使谐振腔在基本相等的长度 在反向传播的泵浦信号的谐振长度之间的一段长度上。 本发明的布里渊光纤陀螺仪还提供了陀螺仪旋转速率的动态范围，其是现有陀螺仪的动态范围的两倍。
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公开(公告)号：US5022732A
公开(公告)日：1991-06-11
申请号：US342947
申请日：1989-04-25
申请人： Helge E. Engan , Byoung Y. Kim , James N. Blake , Herbert J. Shaw
发明人： Helge E. Engan , Byoung Y. Kim , James N. Blake , Herbert J. Shaw
CPC分类号： G02B6/2821 , G02B6/14 , 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. An acoustic wave is induced in a generator having a gradual tapered cross-section. The generator preferably has the shape of a horn and is coaxially mounted with said optical fiber, so as to suppress the acoustic wave induced in the optical fiber in the reverse direction.
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。 在具有渐变锥形截面的发生器中感应出声波。 发电机优选具有喇叭形状并且与所述光纤同轴安装，以便抑制在相反方向上在光纤中感应的声波。
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7.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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公开(公告)号：US5108183A
公开(公告)日：1992-04-28
申请号：US565248
申请日：1990-08-09
CPC分类号： G01C19/721 , G01P3/36
摘要： An improved broadband light source for a Sagnac interferometer includes a waveguide, such as a fluorescent optical fiber, that is pumped by a pump source with a sufficient intensity to generate temporally incoherent light. The fluorescent optical fiber has first and second ends, one end being an input end of the fiber. The broadband light is provided at an output of the fluorescent optical fiber and is input to the interferometer. In order to prevent laser oscillations between the light source and the interferometer, one end of the fluorescent optical fiber is formed so as to prevent reflections. The light output from the fluorescent fiber to the interferometer comprises only that light that initially propagates toward the output of the optical fiber. In one embodiment of the light source, the pump light from the pump source is coupled into the fluorescent optical fiber in a direction so that it travels away from the output of the fluorescent optical fiber towards the first end. In an alternative embodiment, the fluorescent optical fiber is a doubly clad optical fiber having a first acceptance region and a second acceptance region at the first end. The pump light is introduced into an aperture window between the two acceptance regions so that the pump light can be introduced into the first end at an angle without requiring a reflective surface at the first end.
摘要翻译： 用于Sagnac干涉仪的改进的宽带光源包括诸如荧光光纤的波导，其由泵浦源以足够的强度泵浦以产生时间上不相干的光。 荧光光纤具有第一和第二端，一端是光纤的输入端。 宽带光被提供在荧光光纤的输出处，并被输入到干涉仪。 为了防止光源和干涉仪之间的激光振荡，形成荧光光纤的一端以防止反射。 从荧光纤维到干涉仪的光输出仅包括最初向光纤的输出传播的光。 在光源的一个实施例中，来自泵浦源的泵浦光沿着使得其从荧光光纤的输出朝着第一端行进的方向耦合到荧光光纤中。 在替代实施例中，荧光光纤是在第一端具有第一接收区和第二接收区的双包层光纤。 泵浦光被引入两个接受区域之间的孔眼窗口中，使得泵浦光可以一角度被引入第一端，而不需要第一端的反射表面。
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公开(公告)号：US5106193A
公开(公告)日：1992-04-21
申请号：US565255
申请日：1990-08-09
CPC分类号： G01B9/0209 , G01B9/0201 , G01C19/64 , G01B2290/70
摘要： An improved broadband light source for a Sagnac interferometer includes a fluorescent optical medium that is pumped by light from a pump source with a sufficient intensity to cause the fluorescent optical medium to generate temporally incoherent light by superfluorescence. In the preferred embodiment, the superfluorescent optical medium comprises an optical fiber which is backward pumped. The signal output from the interferometer loop is amplified by the optical gain of the superfluorescent fiber which acts as a light source and as an amplifier. In order to avoid gain modulation in the superflorescent fiber, the modulation frequency is selected so that the modulation gain depth is substantially reduced.
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公开(公告)号：US4952059A
公开(公告)日：1990-08-28
申请号：US180596
申请日：1988-04-06
IPC分类号： G01C19/64
CPC分类号： G01C19/64
摘要： A re-entrant fiber optic interferometer comprises an optical fiber, forming a loop for recirculating an optical signal in the loop. The loop of optical fiber comprises an active material which emits photons at a first wavelength and responds to pumping in a second wavelength. Signal light at the first wavelength is input to the loop for circulation therein, and pump light at the second wavelength is input to the loop to optically pump the active material to emit light at the first wavelength. The invention also includes a multiplexing coupler which has different coupling ratios for the pump light and the signal light, such that only a fraction of the signal light is coupled out of the loop on each circulation about the loop, but substantially all of the pump light is coupled out of the loop after a single circulation, thereby suppressing pump phase noise in the loop.
摘要翻译： 入侵者光纤干涉仪包括光纤，形成用于使环路中的光信号循环的环路。 光纤的环路包括发射第一波长的光子并响应于第二波长的泵浦的活性材料。 将第一波长的信号光输入到循环中循环，并将第二波长的泵浦光输入到环路以光学泵浦活性物质以发射第一波长的光。 本发明还包括对泵浦光和信号光具有不同耦合比的多路复用耦合器，使得只有一部分信号光在围绕环路的每个循环上耦合到环路外，而基本上所有的泵浦光 在单循环之后被耦合到环路外，从而抑制回路中的泵相位噪声。
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