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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：US4964131A
公开(公告)日：1990-10-16
申请号：US319241
申请日：1989-03-09
IPC分类号： G01C19/72 , H01S3/067 , H01S3/094 , H01S3/0941
CPC分类号： G01C19/721 , H01S3/06795 , H01S3/0941 , H01S3/094003
摘要： An optical fiber laser includes a single-mode optical fiber doped with a lasing material such as Neodymium. The optical fiber is pumped with a pump optical signal having a pump wavelength selected to cause spontaneous emission of an optical signal at a second wavelength different from the pump wavelength. The optical fiber is formed into a laser cavity such as by including a suitable reflector at each of the two ends of a suitable length of the optical fiber so that the emitted optical signal oscillates therein. One of the reflectors has a reflectivity at the wavelength of the emitted light so that most (e.g., approximately 95%) of the emitted light is reflected back into the laser cavity and a smaller portion (e.g, approximately 5%) is transmitted through the mirror as a laser output signal. Alternatively, the optical fiber can be formed into a ring laser structure using an optical coupler that couples a substantial portion (e.g., approximately 95%) of the emitted light back into the ring for recirculation therein and provides a smaller portion of the emitted light (e.g., approximately 5%) as a laser output signal. The wavelength of the pump optical signal is selected to be outside the pump variable tuning range of the Neodymium-doped optical fiber (i.e., the range of pump wavelengths which stimulate emitted wavelengths having a average wavelengths with a generally one-to-one correspondence to the pump wavelength). Pumping with a pump signal outside the pump variable tuning ranges causes the emitted light to have a broad spectral envelope of longitudinal modes having emission wavelengths corresponding to substantially all the pump variable tuning range. Thus, by pumping the optical fiber with a single pump wavelength, a broadband laser output signal is generated.
摘要翻译： 光纤激光器包括掺杂有诸如钕的激光材料的单模光纤。 用选择了泵浦波长的泵浦光信号来泵浦光纤，以引起与泵浦波长不同的第二波长的光信号的自发发射。 光纤被形成为激光腔，例如通过在光纤的适当长度的两端中的每一端包括合适的反射器，使得所发射的光信号在其中振荡。 反射器中的一个在发射光的波长处具有反射率，使得大部分（例如，大约95％）的发射光被反射回到激光腔中，并且较小的部分（例如，大约5％）通过 镜像为激光输出信号。 或者，可以使用光耦合器将光纤形成为环形激光器结构，所述光耦合器将发射的光的大部分（例如，大约95％）重新连接到环中以在其中再循环，并且提供较小部分的发射光 例如约5％）作为激光输出信号。 泵浦光信号的波长被选择在掺杂钕光纤的泵可变调谐范围之外（即，泵浦波长的范围，其激发平均波长与一般一一对应的发射波长 泵浦波长）。 在泵可变调谐范围之外用泵浦信号泵送使得发射的光具有宽泛的光谱包络，其具有与基本上所有泵可变调谐范围对应的发射波长的纵向模式。 因此，通过用单个泵浦波长泵浦光纤，产生宽带激光输出信号。
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公开(公告)号：US4938556A
公开(公告)日：1990-07-03
申请号：US281088
申请日：1988-12-07
IPC分类号： H01S3/067 , H01S3/0933 , H01S3/094 , H04B10/17 , H04J14/02
CPC分类号： H04B10/2912 , H01S3/0933 , H01S3/094003 , H04B10/291 , H04J14/02 , H01S3/06787 , H01S3/094011
摘要： A superfluorescent broadband fiber laser source comprises a fiber doped with laser material coupled to a multiplexing coupler. In the preferred embodiment, a source of pumping illumination provides pumping light to the doped fiber, and the coupler is adjusted to have a 0% coupling efficiency at the wavelength of the source. The pumping light is sufficiently intense to produce amplified spontaneous emission within the doped fiber, and gives rise to a forward signal and a backward signal. One of the superfluorescent signals is reflected back to the doped fiber by a reflector cemented to one end of the doped fiber or to one end of another fiber through the coupling function of the coupler. The coupler is adjusted to provide complete coupling at the frequency of the lasing light. The temperature dependence of the coupler can be selected to reduce or cancel the temperature dependence of the superfluorescent signal. Other arrangements utilizing the multiplexing properties of the coupler are also described. An all-fiber reflector can also be used.
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公开(公告)号：US4836676A
公开(公告)日：1989-06-06
申请号：US946628
申请日：1986-12-29
申请人： Byoung Y. Kim , Herbert J. Shaw
发明人： Byoung Y. Kim , Herbert J. Shaw
IPC分类号： G01C19/72
CPC分类号： G01C19/72
摘要： A system and method for detecting the influence of selected forces on an interferometer over an extended dynamic range. One presently preferred embodiment is disclosed for detecting rotation of an interferometer. In this embodiment, an open-loop, all-fiber-optic gyroscope provides an output signal comprising the phase difference of two light waves which are counterpropagating within the gyroscope, and which are phase modulated at a selected frequency. The phase difference of the light waves is influenced by the rotation rate of the interferometer. The output signal is amplitude modulated at the phase modulation frequency to transpose the optical phase shift into a low frequency electronic phase shift, which is measured using a digital time interval counter. A linear scale factor is achieved through use of this system and method.
摘要翻译： 一种用于在扩展动态范围内检测所选力对干涉仪的影响的系统和方法。 公开了一种目前优选的实施例，用于检测干涉仪的旋转。 在该实施例中，开环全光纤陀螺仪提供包括在陀螺仪内相反传播的两个光波的相位差并且以所选频率进行相位调制的输出信号。 光波的相位差受到干涉仪的旋转速度的影响。 输出信号以相位调制频率进行幅度调制，以将光相位转换成低频电子相移，其使用数字时间间隔计数器测量。 通过使用该系统和方法实现线性比例因子。
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