公开(公告)号：US06281838B1

公开(公告)日：2001-08-28

申请号：US09302533

申请日：1999-04-30

申请人： John H. Hong

发明人： John H. Hong

IPC分类号： H01Q336

CPC分类号： H01Q3/36 ,  H01G5/18 ,  H01G5/40 ,  H01Q3/38

摘要： A phased array antenna phase shifter having one or more serially connected stages, the stages allowing a transmission signal to pass through to a radiating element. Each of the stages have three or more delay lines for imparting a different respective delay on the transmission signal and a network of switches to select which of the delay lines within the stage will carry the transmission signal. As the signal is passed through each of the stages, the signal will experience the cumulative delays from the stages of the phase shifter. The delay lines in each stage comprise delay lines of different respective lengths, a delay is imparted on the transmission signal as it passed along the length of the selected delay line. The network of switches comprises micro electromechanical systems (MEMS) switches.

摘要翻译： 具有一个或多个串联连接级的相控阵天线移相器，所述级允许传输信号通过辐射元件。 每个级具有三个或更多个延迟线，用于在传输信号上施加不同的相应延迟，以及开关网络，以选择级内的哪些延迟线将承载传输信号。 当信号通过每个级时，信号将经历来自移相器的级的累积延迟。 每个级中的延迟线包括不同相应长度的延迟线，当传输信号沿所选择的延迟线的长度通过时，延迟被赋予传输信号。 开关网络包括微机电系统（MEMS）开关。

公开(公告)号：US5689351A

公开(公告)日：1997-11-18

申请号：US574464

申请日：1995-12-07

申请人： John H. Hong

发明人： John H. Hong

IPC分类号： G03H1/04 ,  G03H1/28 ,  G03H1/10 ,  G03H1/12 ,  G03H1/22 ,  G11C7/00

CPC分类号： G03H1/0248 ,  G03H1/28

摘要： A method and apparatus are provided for reducing speckle noise in images read out from holographic memories. An image recorded in the memory is read out using a multiple component readout beam, with each component having the same horizontal orientation but a different vertical orientation. Because the Bragg effect is pronounced only in the horizontal direction, the readout beam components all access the same stored image. Each readout beam component is set to oscillate at a slightly different frequency such that the smallest frequency difference is greater than the reciprocal of the output detector response time. The multiple oscillating readout beam components can be produced by an acoustooptic deflector driven by a wideband electrical signal. The memory readout comprises multiple reconstructions of the desired image, with each image reconstruction oscillating at a slightly different optical frequency. The output detector receives a set of mutually incoherent image reconstructions that reduce the speckle noise through an image averaging effect, thereby improving the quality of the output image.

摘要翻译： 提供了一种用于减少从全息存储器读出的图像中的斑点噪声的方法和装置。 使用多分量读出光束读出记录在存储器中的图像，其中每个分量具有相同的水平取向但不同的垂直取向。 由于布拉格效应仅在水平方向上显现，所以读出光束分量全部访问相同的存储图像。 每个读出光束分量被设置为以稍微不同的频率振荡，使得最小的频率差大于输出检测器响应时间的倒数。 可以通过由宽带电信号驱动的声光偏转器来产生多个振荡读出光束分量。 存储器读出包括所需图像的多次重建，每个图像重建以略微不同的光学频率振荡。 输出检测器接收一组相互非相干的图像重建，通过图像平均效应减少斑点噪声，从而提高输出图像的质量。

公开(公告)号：US5283672A

公开(公告)日：1994-02-01

申请号：US878147

申请日：1992-05-04

申请人： John H. Hong ,  Pochi A. Yeh

发明人： John H. Hong ,  Pochi A. Yeh

IPC分类号： G02B23/00 ,  G03H1/00 ,  G03H1/26 ,  G03H1/02

CPC分类号： G03H1/00 ,  G02B23/00 ,  G03H1/26

摘要： Holographic apparatus and methods are provided for generating high resolution telescopic images using low cost, small aperture lenses. Holographic media, such as photorefractive crystals, are used in conjunction with multiple and/or synthetic aperture techniques. In a multiple aperture system, a thin nonlinear holographic medium is used with a plurality of small optical lenses to compensate for the inherent piston and tilt errors of the lenses, thereby providing higher resolution. In another embodiment, synthetic aperture techniques are accomplished by illuminating a far field object with coherent light, deriving a reference beam from the coherent light, and changing the position of the reference beam in accordance with a computational formula. A hologram is formed from a sequence of image exposures in the holographic media, each made at different positions with respect to the image. The sequence of exposures is combined and phased in the holographic media to synthesize a high resolution image normally achievable only with a relatively larger aperture.

摘要翻译： 提供了全息设备和方法，用于使用低成本，小孔径透镜产生高分辨率望远镜图像。 全息介质，例如光折射晶体，与多种和/或合成孔径技术结合使用。 在多孔径系统中，薄的非线性全息介质与多个小的光学透镜一起使用以补偿透镜的固有的活塞和倾斜误差，从而提供更高的分辨率。 在另一个实施例中，通过用相干光照射远场物体，从相干光导出参考光束并根据计算公式改变参考光束的位置来实现合成孔径技术。 全息图由全息图像中的图像曝光序列形成，每个图像在相对于图像的不同位置处制成。 将曝光序列组合并定相在全息介质中以合成通常只能通过相对较大孔径可实现的高分辨率图像。

公开(公告)号：US5191448A

公开(公告)日：1993-03-02

申请号：US780595

申请日：1991-10-23

申请人： Frederick R. Vachss ,  John H. Hong

发明人： Frederick R. Vachss ,  John H. Hong

IPC分类号： G02F1/03 ,  G03H1/06 ,  G06E3/00

CPC分类号： G02F1/0338 ,  G03H1/06 ,  G06E3/001 ,  G03H2001/026 ,  G03H2001/0268

摘要： A photorefractive device is provided for converting an image-bearing incoherent input beam to a high contrast coherent output beam the intensity of which varies as the square of the input intensity pattern. The device uses an incoherent image beam to write a holographic grating directly in a photorefractive medium. In one embodiment, a parallel, laterally displaced, telecentric system of lenses is used to split a quasi-monochromatic, incoherent image-bearing beam into two equal components. The two components are superimposed at the surface of the photorefractive medium to produce the hologram. In a second embodiment, the incoherent input beam is directed through a physically translating external grating to write the hologram in the photorefractive medium. The moving grating improves the diffraction efficiency of the hologram under the influence of an applied electric field and stabilizes the temporal response characteristics for signal processing. In both embodiments, the photorefractive medium is exposed to a coherent beam that picks up the image from the hologram and produces a coherent output beam having a high contrast replica of the input image.

摘要翻译： 提供了一种光折射装置，用于将具有影像的非相干输入光束转换成高对比度相干输出光束，其强度随着输入强度图案的平方而变化。 该器件使用非相干图像光束将全息光栅直接写入光折射介质中。 在一个实施例中，使用平行的，横向移位的远心透镜系统将准单色非相干图像承载梁分成两个相等的部件。 两个分量叠加在光折射介质的表面以产生全息图。 在第二实施例中，非相干输入光束被引导通过物理平移的外部光栅以将全息图写入光折射介质中。 移动光栅在施加的电场的影响下提高了全息图的衍射效率，并稳定了信号处理的时间响应特性。 在两个实施例中，光折射介质暴露于从全息图拾取图像的相干光束，并产生具有输入图像的高对比度副本的相干输出光束。

公开(公告)号：US5050967A

公开(公告)日：1991-09-24

申请号：US351228

申请日：1989-05-15

申请人： John H. Hong

发明人： John H. Hong

IPC分类号： G02B6/28 ,  H03H9/00

CPC分类号： G02B6/2861

摘要： Nonlinear optical techniques are utilized to provide an adaptive notch filter for removing narrowband noise from broadband RF communication signals. The received RF signal is converted to a corresponding acoustic wave propagated in an acousto-optic cell. Two mutually coherent beams of light are passed through and diffracted by the acousto-optic cell. The diffracted beams are modulated by the acoustic wave, the second beam being modulated at a predetermined time delay with respect to the first beam. By proper selection of the time delay, the narrowband components of the two beams remain mutually coherent while the broadband components become mutually incoherent. The two diffracted beams are then mixed within a photorefractive crystal so that a first mixed beam comprises substantially all of the narrowband components while a second mixed beam consists essentially of only the broadband components. The second mixed beam is then detected and processed to filter out the time delay echo, leaving the useful broadband signal without the narrowband noise.

摘要翻译： 非线性光学技术被用于提供用于从宽带RF通信信号中去除窄带噪声的自适应陷波滤波器。 所接收的RF信号被转换成在声光单元中传播的对应的声波。 两个相互相干的光束被声光电池通过并衍射。 衍射光束被声波调制，第二光束相对于第一光束以预定的时间延迟被调制。 通过适当选择时间延迟，两个波束的窄带分量保持相互相干，而宽带分量变得相互不相干。 然后将两个衍射光束在光折变晶体内混合，使得第一混合光束基本上包括所有窄带分量，而第二混合光束基本上仅由宽带分量组成。 然后检测和处理第二混合光束以滤除时间延迟回波，留下有用的宽带信号而没有窄带噪声。

公开(公告)号：US5039988A

公开(公告)日：1991-08-13

申请号：US275994

申请日：1988-11-25

申请人： John H. Hong

发明人： John H. Hong

IPC分类号： G02F7/00 ,  H03M1/74

CPC分类号： H03M1/74 ,  G02F7/00

摘要： A device is provided for converting optical digital signals to electronic analog signals. A light beam is passed through a series of beam splitters. The transmission coefficient of each beam splitter is equal to the reciprocal of the base of the number of the electronic digital input signal. The beam splitters are arranged in series with the light beam so that the reflected portion of the beam is weighted to be proportional to the significance of a place in the binary number corresponding to its beam splitter. The reflected portion of the beam from each beam splitter is separately modulated in response to an input electronic digital signal for the place in the digital number corresponding to its beam splitter. The reflected portions of the beam from each beam splitter are combined and the combined beam is received by a detector which provides an electronic output which is an analog representation of the digital signal.

摘要翻译： 提供了一种用于将光学数字信号转换成电子模拟信号的装置。 光束通过一系列光束分离器。 每个分束器的透射系数等于电子数字输入信号数量的基数的倒数。 分束器与光束串联布置，使得光束的反射部分被加权成与对应于其分束器的二进制数的位置的重要性成比例。 来自每个分束器的光束的反射部分响应于用于对应于其分束器的数字编号的位置的输入电子数字信号被单独调制。 来自每个分束器的光束的反射部分被组合，组合光束由提供作为数字信号的模拟表示的电子输出的检测器接收。

公开(公告)号：US5025488A

公开(公告)日：1991-06-18

申请号：US437968

申请日：1989-11-16

申请人： Pochi A. Yeh ,  John H. Hong

发明人： Pochi A. Yeh ,  John H. Hong

IPC分类号： G02F2/00 ,  H04B10/148

CPC分类号： H04B10/60 ,  G02F2/002 ,  H04B10/64

摘要： Nonlinear optical devices and techniques are used to provide heterodyne detection for coherent optical communications. Heterodyne detection is achieved by matching the wave front of a local oscillator beam with the wave front of a received optical signal. Precise wave front matching provides high heterodyne efficiency and a wide field of view. In one embodiment, the received signal and a reference beam of the same frequency are directed into a nonlinear medium to form a volume hologram that contains the spatial information of the received signal. The reference beam is alternated with a local oscillator beam that has the same wave front and is parallel to the reference beam but at a different frequency. The hologram matches the wave fronts of the signal beam and the local oscillator beam to produce a large heterodyne signal. In an alternative embodiment, the received signal beam and the local oscillator beam are directed into a mutually pumped phase conjugator (MPPC). The MPPC generates a spatial phase conjugate of the oscillator beam that carries the temporal characteristics of the signal beam. A beam splitter combines the information carrying phase conjugate beam with a phase conjugate of the pure local oscillator beam returned by a phase conjugate mirror. The two phase conjugate beams arrive at the plane of a photodetector with precisely the same wave front and direction. The matched wave fronts produce high heterodyne efficiency, and the automatic tracking feature of the phase conjugators provides a wide field of view.

摘要翻译： 非线性光学器件和技术用于提供相干光通信的外差检测。 通过将本地振荡器的波前与接收的光信号的波前匹配来实现异步检测。 精确的波前匹配提供了高外差效率和广泛的视野。 在一个实施例中，将接收的信号和相同频率的参考光束引导到非线性介质中以形成包含接收信号的空间信息的体积全息图。 参考光束与具有相同波前并且平行于参考光束但以不同频率的本地振荡器光束交替。 全息图与信号光束和本地振荡器波束相匹配，产生大的外差信号。 在替代实施例中，接收的信号波束和本地振荡器波束被引导到相互泵浦的相位共轭器（MPPC）中。 MPPC产生携带信号束的时间特性的振荡器波束的空间相位共轭。 分束器将信息携带相位共轭光束与由相位共轭反射镜返回的纯局部振荡器光束的相位共轭相结合。 两相共轭光束到达具有精确相同的波前和方向的光电检测器的平面。 匹配波阵面产生高外差效率，相位共轭器的自动跟踪特性提供了广泛的视野。

公开(公告)号：US4965603A

公开(公告)日：1990-10-23

申请号：US388789

申请日：1989-08-01

申请人： John H. Hong ,  McMichael, Ian C.

发明人： John H. Hong ,  McMichael, Ian C.

IPC分类号： H01Q3/26

CPC分类号： H01Q3/2676

摘要： An optical beamforming network is provided for controlling the RF radiation pattern of a phased array antenna. Light from a first laser is modulated by a spatial light modulator that is user-programmed with the desired far field radiation footprint. The modulated light beam is directed through a Fourier transform lens and onto a beam splitter where it is combined with light from a second laser that is frequency offset by the RF center frequency of the antenna. Light from the beam splitter is recovered by first and second fiber optic bundles. Each optical fiber leads to a corresponding photodetector that detects the beat frequency produced by the two frequency offset light beams. The outputs of corresponding photodetectors of the two fiber optic bundles are combined to control the radiation of a corresponding radiation element of the phased array. The use of two sets of optical fibers and photodetectors improves the signal-to-noise ratio of the system. An alternative embodiment of the invention uses photorefractive crystals to pass phase conjugate return beams back through the optical lenses to cancel lens-induced aberrations from the spatially modulated light beam. This embodiment reduces distortion of the far field radiation pattern without the use of high quality optical lenses.

摘要翻译： 提供光束成形网络用于控制相控阵天线的RF辐射图。 来自第一激光器的光由空间光调制器调制，空间光调制器是用所需远场辐射足迹进行用户编程的。 调制光束被引导通过傅里叶变换透镜并被引导到分束器上，在该分束器上它与来自天线的RF中心频率偏移的第二激光器的光组合。 来自分束器的光由第一和第二光纤束回收。 每个光纤通向相应的光电检测器，其检测由两个频偏部分产生的拍频。 组合两个光纤束的相应的光电检测器的输出以控制相控阵列的相应辐射元件的辐射。 使用两组光纤和光电探测器提高了系统的信噪比。 本发明的替代实施例使用光折射晶体将相位共轭返回光束通过光学透镜返回以抵消来自空间调制光束的透镜引起的像差。 该实施例减少了远场辐射图的失真，而不使用高质量的光学透镜。