Zhizhong (Jeff) Zhuang
Chester Springs, Pennsylvania, United States
646 followers
500+ connections
About
Result-driven technical professional with diverse background, extensive hands-on…
Articles by Zhizhong (Jeff)
Activity
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When Jack Bogle founded Vanguard in 1975, it was the beginning of an investment revolution. Back then, investing was the exclusive preserve of large…
When Jack Bogle founded Vanguard in 1975, it was the beginning of an investment revolution. Back then, investing was the exclusive preserve of large…
Liked by Zhizhong (Jeff) Zhuang
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Just finished the course “Cybersecurity Awareness: Cybersecurity Terminology”! Check it out: https://lnkd.in/eveSAXVi
Just finished the course “Cybersecurity Awareness: Cybersecurity Terminology”! Check it out: https://lnkd.in/eveSAXVi
Liked by Zhizhong (Jeff) Zhuang
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It’s been a year since I joined Vanguard, I can’t express enough how much I enjoy working with an amazing tech team where I can learn new things…
It’s been a year since I joined Vanguard, I can’t express enough how much I enjoy working with an amazing tech team where I can learn new things…
Liked by Zhizhong (Jeff) Zhuang
Experience
Education
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Penn State University
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Theoretical analysis, and technology development for various fiber optic sensors using liquid crystal.
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Electronics devices, and Integrated circuits fabrication
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New Superconductor materials, and their properties
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Ultra-low temperature physice
Licenses & Certifications
Patents
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Detection and location of boundary intrusion, using composite variables derived from phase measurements
Issued US 8395782
A disturbance, such as vibration from human activity, is located along a fiberoptic waveguide configuration (301-304) with two interferometers (801, 802) of the same or different types, such as Mach-Zehnder, Sagnac, and Michelson interferometers. Carrier signals from a source (101) are split at the interferometer inputs (201, 202) and re-combined at the outputs (701, 702) after propagating through the detection zone (401), where phase variations are induced by the disturbance (501). Phase…
A disturbance, such as vibration from human activity, is located along a fiberoptic waveguide configuration (301-304) with two interferometers (801, 802) of the same or different types, such as Mach-Zehnder, Sagnac, and Michelson interferometers. Carrier signals from a source (101) are split at the interferometer inputs (201, 202) and re-combined at the outputs (701, 702) after propagating through the detection zone (401), where phase variations are induced by the disturbance (501). Phase responsive receivers (901, 902) detect phase relationships (1001, 1002) between the carrier signals over time. A processor (1101) combines the phase relationships into composite signals according to equations that differ for different interferometer configurations, with a time lag between or a ratio of the composite signals representing the location of the disturbance. The detected and composite values are unbounded, permitting phase displacement to exceed the carrier period and allowing disturbances of variable magnitudes to be located.
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Phase responsive optical fiber sensor
Issued US 7725026
The location of a physical disturbance along an optical waveguide is determined by measuring different propagation times for the resulting phase variation to propagate to phase responsive receivers at ends of bidirectional signal paths. Each receiver can have a coupler that functions as a beam combiner and as a beam splitter inserting the opposite signal. On each receiving end, the coupler provides one or more detectors with signals from which phase related independent variable values are…
The location of a physical disturbance along an optical waveguide is determined by measuring different propagation times for the resulting phase variation to propagate to phase responsive receivers at ends of bidirectional signal paths. Each receiver can have a coupler that functions as a beam combiner and as a beam splitter inserting the opposite signal. On each receiving end, the coupler provides one or more detectors with signals from which phase related independent variable values are taken, processed and mapped to phase angles. Relative phase angle versus time is derived for each opposite signal pair and correlated at a time difference, i.e., a difference in propagation time from which the location of the disturbance is resolved. Polarization sensitive and polarization insensitive examples are discussed with various optical fiber arrangements.
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Distributed fiber sensor with interference detection and polarization state management
Issued US 7142736
Polarization effects are managed to provide differential timing information for localizing disturbances affecting two or more counter-propagating light signals on one or more optical waveguides passing through a detection zone. Activity can be localized to a point for a security perimeter. Events causing optical disturbance can be mapped to points along a straight line, a perimeter or arbitrary pattern or an array. Events cause local changes in optical properties in the optical waveguide, in…
Polarization effects are managed to provide differential timing information for localizing disturbances affecting two or more counter-propagating light signals on one or more optical waveguides passing through a detection zone. Activity can be localized to a point for a security perimeter. Events causing optical disturbance can be mapped to points along a straight line, a perimeter or arbitrary pattern or an array. Events cause local changes in optical properties in the optical waveguide, in particular an optical fiber. Short term local changes are distinguishable from phase changes of light travel in the waveguide by managing the polarization state of input and output beams.
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Distributed fiber sensor with detection and signal processing using polarization state management
Issued US 7139476
Polarization effects are managed to provide differential timing information for localizing disturbances affecting two or more counter-propagating light signals on one or more optical waveguides passing through a detection zone. Activity can be localized to a point for a security perimeter. Events causing optical disturbance can be mapped to points along a straight line, a perimeter or arbitrary pattern or an array. Events cause local changes in optical properties in the optical waveguide, in…
Polarization effects are managed to provide differential timing information for localizing disturbances affecting two or more counter-propagating light signals on one or more optical waveguides passing through a detection zone. Activity can be localized to a point for a security perimeter. Events causing optical disturbance can be mapped to points along a straight line, a perimeter or arbitrary pattern or an array. Events cause local changes in optical properties in the optical waveguide, in particular an optical fiber. Short term local changes are distinguishable from phase changes of light travel in the waveguide, by managing the polarization state of input and output beams, combining orthogonal polarization components and other aspects. The changes in the states of polarization of the counter-propagating light signals are determined and the temporal spacing of corresponding changes in polarization state are resolved to pinpoint the location of the event along the optical fiber.
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Over-parameterized polarization controller
Issued US 7085052
A controller, particularly for setting a desired or randomized polarization state of an output light beam derived from an input, has more than the minimum number of controllable optical elements needed to determine the state of the output. The controller applies control input values to obtain a desired output state. The controller also selects among plural alternative sets of control values that could obtain the desired output state, so as to minimize other error conditions. The concurrent…
A controller, particularly for setting a desired or randomized polarization state of an output light beam derived from an input, has more than the minimum number of controllable optical elements needed to determine the state of the output. The controller applies control input values to obtain a desired output state. The controller also selects among plural alternative sets of control values that could obtain the desired output state, so as to minimize other error conditions. The concurrent error conditions can be associated finite control range limits, for example to keep the input values near a middle of their ranges. Additional error conditions can include minimizing the incremental change in the values from one set to the next. The control is particularly useful to avoid problems associated with using finite range control elements such as liquid crystals for differential retardation or orthogonal light components, when controlling an endless or periodic parameter such as polarization. In the preferred arrangement, six retardation cells are used to control two independent variables determining polarization state.
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Wavelength dependent optical attenuator and variable attenuation profile controller
Issued US 7154668
The attenuation profile of an optical system, which defines the power variation as a function of wavelength is adjusted to alter the slope of its contour. The device is useful in a wavelength division modulation system to flatten the profile of an amplifier or the like that has a non uniform power variation with wavelength. The invention adjusts the slope by first providing an input light signal that has a known polarization state, e.g., processing the input into a known phase and amplitude…
The attenuation profile of an optical system, which defines the power variation as a function of wavelength is adjusted to alter the slope of its contour. The device is useful in a wavelength division modulation system to flatten the profile of an amplifier or the like that has a non uniform power variation with wavelength. The invention adjusts the slope by first providing an input light signal that has a known polarization state, e.g., processing the input into a known phase and amplitude relation between orthogonal components, such as plane polarized at a given alignment. The signal is then passed through a series of waveplates. The waveplates have different phase retardation and orientation resulting in wavelength dependent polarization change. According to an inventive aspect, by tuning the phase retardation of multiple tunable waveplates the desired wavelength dependent polarization changes over a useful wavelength range can be produced. At the downstream end of the signal path, a polarization discriminating element such as a polarizer or beam splitter, passes or blocks light energy as a function of polarization, thus converting the variation of polarization state into a variation of amplitude.
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Polarization analysis unit, calibration method and optimization therefor
Issued US 6816261
Measurements at multiple distinct polarization measurement states are taken to define the polarization state of an input, for example to calculate a Stokes vector. High accuracy and/or capability of frequent recalibration are needed, due to the sensitivity of measurement to retardation of the input signal. A multiple measurement technique takes a set of spatially and/or temporally distinct intensity measurements through distinct waveplates and polarizers. These can be optimized as to…
Measurements at multiple distinct polarization measurement states are taken to define the polarization state of an input, for example to calculate a Stokes vector. High accuracy and/or capability of frequent recalibration are needed, due to the sensitivity of measurement to retardation of the input signal. A multiple measurement technique takes a set of spatially and/or temporally distinct intensity measurements through distinct waveplates and polarizers. These can be optimized as to orientation and retardation using initial choices and also using tunable elements, especially controllable birefringence elements. A device matrix defines the response of the device at each of the measurement states. The matrix can be corrected using an iterative technique to revise the device matrix, potentially by automated recalibration. Two input signals (or preferably the same signal before and after a polarization transform) that are known to have a common polarization attribute or other attribute relationship are measured and the common attribute and/or attribute relationship is derived for each and compared. The device matrix is revised, for example by iterative correction or by random search of candidates to improve the accuracy of the device matrix. Optional tunable spectral and temporal discrimination provide additional functions.
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Polarization encoder device
Issued US 7127179
A optical polarization encoding device (16) provides wavelength dependent processing of polychromatic optical signals without prior separation into narrow wavelength bands. Embodiments of the encoding device include a wavelength dependent tunable optical switch (400, 500) and a wavelength tunable optical level controller (600). An encoded signal is processed, (e.g., rerouted or attenuated), as a function of wavelength using polarization dependent devices (18). Desired states of polarization are…
A optical polarization encoding device (16) provides wavelength dependent processing of polychromatic optical signals without prior separation into narrow wavelength bands. Embodiments of the encoding device include a wavelength dependent tunable optical switch (400, 500) and a wavelength tunable optical level controller (600). An encoded signal is processed, (e.g., rerouted or attenuated), as a function of wavelength using polarization dependent devices (18). Desired states of polarization are imparted to optical signals to either direct selected wavelengths to selected output ports (optical switch), or to adjust the level of selected channels or wavelengths (level controller). Desired polarizations are achieved simultaneously at all wavelengths contained within the incoming signal by independently varying the birefringence and/or crystallographic orientation of each variable element within the stack.
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Optical power limiting control
Issued US 6606181
A controllable phase plate has numerous domains that are randomized as to the orientation of their birefringence and can be used in a power limiting control to produces an electrically controllable diffraction pattern having a portion, especially the zero mode axial spot of the pattern, that is directed onto an output aperture such as a pinhole or an optical fiber end. Controlling the phase plate produces an interference peak or null (or an intermediate level) of light, coupled into the output…
A controllable phase plate has numerous domains that are randomized as to the orientation of their birefringence and can be used in a power limiting control to produces an electrically controllable diffraction pattern having a portion, especially the zero mode axial spot of the pattern, that is directed onto an output aperture such as a pinhole or an optical fiber end. Controlling the phase plate produces an interference peak or null (or an intermediate level) of light, coupled into the output aperture. The phase plate preferably comprises a liquid crystal with controllable birefringence. The domains have paired orthogonal orientations, which is a condition that is met in randomized domains. The paired orthogonal orientations make the device polarization insensitive. In a controllable attenuating device, collimating lenses are placed before and after the phase plate along a beam path to focus a clear interference pattern on a screen containing the output aperture. Several variations are disclosed including an electrically controllable phase plate arrangement using liquid crystal controllably birefringent material prepared in a polarization insensitive manner in zones, or preferably by providing random director orientation in a plane.
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Optical polarization encoder
Issued US 6535335
An optical polarization encoding device has been invented which allows wavelength dependent processing of polychromatic optical signals without prior separation into narrow wavelength bands. The invention comprises a stack of variable and fixed birefringent elements which introduces, on passage through the stack, a wavelength dependent polarization onto a polychromatic optical signal of arbitrary polarization. Desired polarizations are achieved simultaneously at all wavelengths contained within…
An optical polarization encoding device has been invented which allows wavelength dependent processing of polychromatic optical signals without prior separation into narrow wavelength bands. The invention comprises a stack of variable and fixed birefringent elements which introduces, on passage through the stack, a wavelength dependent polarization onto a polychromatic optical signal of arbitrary polarization. Desired polarizations are achieved simultaneously at all wavelengths contained within the incoming signal by independently varying the birefringence and/or crystallographic orientation of each element within the stack. The encoded signal may be subsequently be processed, e.g. rerouted or attenuated, as a function of wavelength using polarization dependent devices. The encoding stack is rendered polarization insensitive by dividing the incoming optical signal, with a polarization beam splitter, into two beams of orthogonal polarization prior to passage through the stack.
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Narrow band polarization encoder
Issued US 6611342
An interferometer optical element is provided with a birefringent material in the light path. Specifically, a Fabry-Perot optical resonance cavity is operated in a fully reflective mode and is provided with a birefringent material in a cavity between two reflectors. A first mirror, for example of about 90% reflectance and a second mirror, for example of 99% reflectance, define the cavity. The polarization effect is applied exclusively to the resonant wavelength defined by the spacing of the two…
An interferometer optical element is provided with a birefringent material in the light path. Specifically, a Fabry-Perot optical resonance cavity is operated in a fully reflective mode and is provided with a birefringent material in a cavity between two reflectors. A first mirror, for example of about 90% reflectance and a second mirror, for example of 99% reflectance, define the cavity. The polarization effect is applied exclusively to the resonant wavelength defined by the spacing of the two reflectors. The input beam is fully reflected back in the direction of incidence. However the resonant wavelength component therein is polarized and can be discriminated, e.g., selectively diverted by a polarization beam splitter. A number of application are disclosed, including using a birefringent liquid crystal material and tuning the apparent optical path length by electrically adjusting the birefringence. The device also is cascadable for selectively operating on certain wavelengths and diversely polarizing some wavelengths and not others. In a preferred embodiment, the input beam is applied at 45 degrees to the fast axis of oriented birefringent nematic liquid crystal, which can optionally involve separately altering and recombining diverse polarization components of the input beam.
Projects
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Zemango GPS Tracking for Fleet Management
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Zemango was designed to be a simple, low-cost tracking system that provides high-end features for a business or family's vehicle tracking and reporting needs. The technology started developmental life as a program for the US Army and DARPA, helping troops track friendly forces, but when military funding was scaled back, Aterrasys switched to a more commercial angle.
On this project, I shared the management of the server-side data processing application used for multiple projects…Zemango was designed to be a simple, low-cost tracking system that provides high-end features for a business or family's vehicle tracking and reporting needs. The technology started developmental life as a program for the US Army and DARPA, helping troops track friendly forces, but when military funding was scaled back, Aterrasys switched to a more commercial angle.
On this project, I shared the management of the server-side data processing application used for multiple projects, developed using Java servlets, Spring and Spring Security, Hibernate, and MySQL or PostgreSQL/PostGIS. I am also the principle developer for the HTML5 web, mobile web, and android app.Other creatorsSee project
Languages
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English
Full professional proficiency
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Chinese
Native or bilingual proficiency
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Last year was amazing, full of challenges, but great opportunities for learning and career growth. I became part of the Vanguard family, where I feel…
Last year was amazing, full of challenges, but great opportunities for learning and career growth. I became part of the Vanguard family, where I feel…
Liked by Zhizhong (Jeff) Zhuang
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Excited to see a product I’m working on in one of my favorite stores!
Excited to see a product I’m working on in one of my favorite stores!
Liked by Zhizhong (Jeff) Zhuang
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At Vanguard, our mobile app is taking center stage! Interested in helping us build it? Check the link below to join our talent community. Let's make…
At Vanguard, our mobile app is taking center stage! Interested in helping us build it? Check the link below to join our talent community. Let's make…
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#DYK that 2023 commemorates three decades of exceptional brands, cutting-edge products and captivating shows on QVC UK? That’s right, October 1st…
#DYK that 2023 commemorates three decades of exceptional brands, cutting-edge products and captivating shows on QVC UK? That’s right, October 1st…
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Let's tune! The Land Down Under 🇦🇺 🥳 First place - Top Paid App - Category music https://lnkd.in/dxyYRiJA
Let's tune! The Land Down Under 🇦🇺 🥳 First place - Top Paid App - Category music https://lnkd.in/dxyYRiJA
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I’m super excited to join the Grace Hopper conference for the first time and representing Vanguard. I will be joining other Vanguard women with…
I’m super excited to join the Grace Hopper conference for the first time and representing Vanguard. I will be joining other Vanguard women with…
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