Patents Assigned to Essex Corporation
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Patent number: 7720226Abstract: A method and apparatus for secure transmission of an information-containing optical signal. An optical signal is divided into a first plurality of sub-bands. Each of the sub-bands is modified to encrypt the information contained in the optical signal. The modified sub-bands are combined into a combined optical signal. The combined optical signal is divided into a second plurality of sub-bands. Each of the second plurality of sub-bands is modified to decrypt the previously encrypted information contained in the optical signal.Type: GrantFiled: November 19, 2003Date of Patent: May 18, 2010Assignee: Essex CorporationInventor: Terry M. Turpin
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Patent number: 7509048Abstract: An Optical Tapped Delay Line (OTDL), which resolves multiple wavelength signals having extremely narrow wavelength spacing, is combined with other known optical devices to provide a wide variety of optical signal processing applications, including: multiplexing and de-multiplexing a multi-channel signal; adding a signal to, or dropping a signal from, a multi-channel optical signal; specialized coding processing such as generating code division multiple access signals; wavelength locking (stabilizing) a signal; filtering a signal; and analyzing and monitoring a signal spectrum. The OTDL spatially separates individual channels to allow separate processing on each channel. Fixed and tunable embodiments are identified in appropriate cases. Bulk, hybrid, and integrated optical embodiment and methods of fabrication are described, as are curved self-focusing and evanescent embodiments of OTDL devices.Type: GrantFiled: July 22, 2002Date of Patent: March 24, 2009Assignee: Essex CorporationInventors: Terry M. Turpin, Craig H. Price, Fred F. Froelich, Bruce D. Nichols, James L. Lafuse, Keith R. Frampton
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Publication number: 20070165310Abstract: A method of controlling phase on at least one of reflectance and transmission in an optic device. The optic device includes a multiple layer stack. At least one dimension of a first layer in the stack is varied in at least a first direction. At least one dimension of a second layer in the stack is varied in at least a second direction. The first direction and the second direction are substantially opposite. The stack is maintained at a substantially constant optical thickness.Type: ApplicationFiled: August 11, 2006Publication date: July 19, 2007Applicant: Essex CorporationInventor: Ricky Nubling
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Patent number: 7130292Abstract: A method and apparatus for enhancing the receiving and information identification functions of multiple access communications systems by employing one or more optical processors configured as a bank of 1-D correlators. The present invention is particularly useful in a DS/SS CDMA communications system, resulting in a multiuser CDMA system that approaches carrier to noise performance (C/N) as opposed to being limited by multiple access interference (MAI). The correlators are arranged in parallel to detect and/or demodulate the received signal, in conjunction with one or more complex algorithms to perform near-optimum multiuser detection, perform multipath combining and/or perform carrier Doppler compensation.Type: GrantFiled: January 19, 2001Date of Patent: October 31, 2006Assignee: Essex CorporationInventors: Terry M. Turpin, James L. Lafuse
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Patent number: 7062174Abstract: An Optical Tapped Delay Line (OTDL) is combined with other known optical apparatuses to provide an add-drop multiplexer for a wavelength division multiplexing fiber optic network. Each output beam of the OTDL is spatially distinguishable in free space. This wavelength accessibility enables selection of one or more of the optical beams for adding or dropping. The system can be a fixed or tunable single channel add/drop system, a fixed or tunable multi-channel add/drop system, or a fully programmable add/drop system.Type: GrantFiled: January 22, 2002Date of Patent: June 13, 2006Assignee: Essex CorporationInventors: Terry M. Turpin, Keith R. Frampton
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Patent number: 7042386Abstract: Methods for mitigating sidelobes and aliases, providing levels of suppression in excess of 20 dB. The methods may include 1) a version of the CLEAN algorithm developed in radio astronomy, modified to work on sub-aperture images; 2) weighting functions based on the phase and amplitude statistics of the sub-aperture image pixels to select points in the CLEAN algorithm; and 3) weighting functions based on the phase and amplitude statistics of the sub-aperture image pixels to mitigate sidelobes and aliases, in conjunction with CLEAN or separately. The methods may be used with all synthetic aperture techniques and are not limited to SAR.Type: GrantFiled: April 28, 2004Date of Patent: May 9, 2006Assignee: Essex CorporationInventors: Paul W. Woodford, Gerald Davieau, James L. Lafuse
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Patent number: 6735346Abstract: A collected data is divided into M single valued subsets, where M is greater than zero. A two-dimensional subset image is formed from each single valued subset. Then, a fast Fourier transform is performed on each image to obtain a two-dimensional subset frequency space. Next, a one-dimensional discrete Fourier transform in z, where z is an integer equal to or greater than zero, is performed. Lastly, a two-dimensional discrete Fourier transform in (x,y) for each value of z is performed, thereby forming the three-dimensional volume from the collected data set.Type: GrantFiled: December 11, 2001Date of Patent: May 11, 2004Assignee: Essex CorporationInventors: Paul W. Woodford, Fred F. Froehlich
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Patent number: 6608721Abstract: An OTDL device in accordance with the present invention is a method for and device for spatially resolving the wavelengths in an optical signal, i.e., channelizing or demultiplexing. The device is based on a tapped optical delay line.Type: GrantFiled: October 13, 2000Date of Patent: August 19, 2003Assignee: Essex CorporationInventors: Terry M. Turpin, Fred F. Froehlich, D. Bruce Nichols
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Patent number: 5751243Abstract: A method and apparatus for producing an image of a target area, by: at an observation location spaced from the target area, transmitting a beam of electromagnetic radiation toward the target area, and receiving reflections of the radiation from the target area; providing a representation of the magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; varying the spatial relation between the observation location and the target area and/or the given radiation frequency, in order to establish a plurality of different observation states which succeed one another in time, each state being associated with a distinct combination of magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; producing two coherent radiation beams, directing the two beams onto a receiving plane provided with an array of radiation receiving cells and storiType: GrantFiled: December 20, 1996Date of Patent: May 12, 1998Assignee: Essex CorporationInventor: Terry M. Turpin
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Patent number: 5736958Abstract: A method and apparatus for producing an image of a target area, by: at an observation location spaced from the target area, transmitting a beam of electromagnetic radiation toward the target area, and receiving reflections of the radiation from the target area; providing a representation of the magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; varying the spatial relation between the observation location and the target area and/or the given radiation frequency, in order to establish a plurality of different observation states which succeed one another in time, each state being associated with a distinct combination of magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; producing two coherent radiation beams, directing the two beams onto a receiving plane provided with an array of radiation receiving cells and storiType: GrantFiled: April 15, 1997Date of Patent: April 7, 1998Assignee: Essex CorporationInventor: Terry M. Turpin
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Patent number: 5623360Abstract: Optical systems are disclosed which are capable of generating and rapidly changing time delays of electrical signals for true time delay beam formation and beam steering and for signal processing applications. The systems utilize an interferometer configuration. A first optical modulator in a first leg of the interferometer is used to modulate coherent light with the signal to be delayed. In a second leg of the interferometer, a second optical modulator provides beam steering to a prism stack, which produces a set of plane reference waves having a range of orientations required to generate a desired range of time delays. Preferably the optical modulators are acousto optic Bragg cells. Alternatively, a stack of lens pairs or diffractive optical elements or a holographic optic element may be used in place of the prism stack. The modulated optical signal from the first leg interferes on an array of photodiodes with the reference waves from the second leg.Type: GrantFiled: February 13, 1995Date of Patent: April 22, 1997Assignee: Essex CorporationInventors: Leslie H. Gesell, Terry M. Turpin
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Patent number: 5390046Abstract: Optical systems are disclosed which are capable of generating and rapidly changing time delays of electrical signals for true time delay beam formation and beam steering and for signal processing applications. The systems utilize an interferometer configuration. A first optical modulator in a first leg of the interferometer is used to modulate coherent light with the signal to be delayed. In a second leg of the interferometer, a second optical modulator provides beam steering to a prism stack, which produces a set of plane reference waves having a range of orientations required to generate a desired range of time delays. Preferably the optical modulators are acousto optic Bragg cells. Alternatively, a stack of lens pairs or diffractive optical elements or a holographic optic element may be used in place of the prism stack. The modulated optical signal from the first leg interferes on an array of photodiodes with the reference waves from the second leg.Type: GrantFiled: April 12, 1993Date of Patent: February 14, 1995Assignee: Essex CorporationInventors: Leslie H. Gesell, Terry M. Turpin
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Patent number: 5384573Abstract: A method and apparatus for producing an image of a target area, by: at an observation location spaced from the target area, transmitting a beam of electromagnetic radiation toward the target area, and receiving reflections of the radiation from the target area; providing a representation of the magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; varying the spatial relation between the observation location and the target area and/or the given radiation frequency, in order to establish a plurality of different observation states which succeed one another in time, each state being associated with a distinct combination of magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; producing two coherent radiation beams, directing the two beams onto a receiving plane provided with an array of radiation receiving cells and storiType: GrantFiled: March 17, 1993Date of Patent: January 24, 1995Assignee: Essex CorporationInventor: Terry M. Turpin
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Patent number: 5202776Abstract: Optical systems are disclosed which are capable of generating and rapidly changing time delays of electrical signals for true time delay beam formation and beam steering. The systems utilize an interferometer configuration. A first optical modulator and a Fourier transform lens define a Fourier transform plane in a first leg of the interferometer. In a second leg of the interferometer, a second optical modulator provides beam steering to a prism stack, which produces a set of plane reference waves having a range of orientations required to generate a desired range of time delays. Preferably the optical modulators are acousto optic Bragg cells. Alternatively, a holographic optic element could be used in place of the prism stack.Type: GrantFiled: December 12, 1991Date of Patent: April 13, 1993Assignee: Essex CorporationInventors: Leslie H. Gesell, James L. Lafuse
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Patent number: 5079555Abstract: A method and apparatus for producing an image of a target area, by: at an observation location spaced from the target area, transmitting a beam of electromagnetic radiation toward the target area, and receiving reflections of the radiation from the target area; providing a representation of the magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; varying the spatial relation between the observation location and the target area and/or the given radiation frequency, in order to establish a plurality of different observation states which succeed one another in time, each state being associated with a distinct combination of magnitude and direction of the distance between points on the target area which produce reflections that travel in phase to the observation location; producing two coherent radiation beams, directing the two beams onto a receiving plane provided with an array of radiation receiving cells and storiType: GrantFiled: October 29, 1990Date of Patent: January 7, 1992Assignee: Essex CorporationInventor: Terry M. Turpin