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  • 1
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    Low-Noise Free-Running High-Rate Photon-Counting for Space Communication and Ranging (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: We present performance data for low-noise free-running high-rate photon counting method for space optical communication and ranging. NASA GSFC is testing the performance of two types of novel photon-counting detectors 1) a 2x8 mercury cadmium telluride (HgCdTe) avalanche array made by DRS Inc., and a 2) a commercial 2880-element silicon avalanche photodiode (APD) array. We successfully measured real-time communication performance using both the 2 detected-photon threshold and logic AND-gate coincidence methods. Use of these methods allows mitigation of dark count, after-pulsing and background noise effects without using other method of Time Gating The HgCdTe APD array routinely demonstrated very high photon detection efficiencies (50) at near infrared wavelength. The commercial silicon APD array exhibited a fast output with rise times of 300 ps and pulse widths of 600 ps. On-chip individually filtered signals from the entire array were multiplexed onto a single fast output. NASA GSFC has tested both detectors for their potential application for space communications and ranging. We developed and compare their performances using both the 2 detected photon threshold and coincidence methods.
    Keywords: Communications and Radar
    Type: GSFC-E-DAA-TN30952 , SPIE Photonics West; Feb 13, 2016 - Feb 18, 2016; San Francisco, CA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Low-Noise Free-Running High-Rate Photon-Counting for Space Communication and Ranging (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: We present performance data for low-noise free-running high-rate photon counting method for space optical communication and ranging. NASA GSFC is testing the performance of two types of novel photon-counting detectors 1) a 2x8 mercury cadmium telluride (HgCdTe) avalanche array made by DRS Inc., and a 2) a commercial 2880-element silicon avalanche photodiode (APD) array. We successfully measured real-time communication performance using both the 2 detected-photon threshold and logic AND-gate coincidence methods. Use of these methods allows mitigation of dark count, after-pulsing and background noise effects without using other method of Time Gating The HgCdTe APD array routinely demonstrated very high photon detection efficiencies ((is) greater than 50%) at near infrared wavelength. The commercial silicon APD array exhibited a fast output with rise times of 300 ps and pulse widths of 600 ps. On-chip individually filtered signals from the entire array were multiplexed onto a single fast output. NASA GSFC has tested both detectors for their potential application for space communications and ranging. We developed and compare their performances using both the 2 detected photon threshold and coincidence methods.
    Keywords: Communications and Radar
    Type: GSFC-E-DAA-TN30890 , SPIE Photonics West; Feb 13, 2016 - Feb 18, 2016; San Francisco, CA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    High Precision Ranging and Range-Rate Measurements over Free-Space-Laser Communication Link (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: We present a high-precision ranging and range-rate measurement system via an optical-ranging or combined ranging-communication link. A complete bench-top optical communication system was built. It included a ground terminal and a space terminal. Ranging and range rate tests were conducted in two configurations. In the communication configuration with 622 data rate, we achieved a two-way range-rate error of 2 microns/s, or a modified Allan deviation of 9 x 10 (exp -15) with 10 second averaging time. Ranging and range-rate as a function of Bit Error Rate of the communication link is reported. They are not sensitive to the link error rate. In the single-frequency amplitude modulation mode, we report a two-way range rate error of 0.8 microns/s, or a modified Allan deviation of 2.6 x 10 (exp -15) with 10 second averaging time. We identified the major noise sources in the current system as the transmitter modulation injected noise and receiver electronics generated noise. A new improved system will be constructed to further improve the system performance for both operating modes.
    Keywords: Communications and Radar
    Type: GSFC-E-DAA-TN28840 , IEEE Aerospace Conference; Mar 05, 2016 - Mar 12, 2016; Big Sky, MT; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    Femtosecond Photon-Counting Receiver (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: An optical correlation receiver is described that provides ultra-precise distance and/or time/pulse-width measurements even for weak (single photons) and short (femtosecond) optical signals. A new type of optical correlation receiver uses a fourth-order (intensity) interferometer to provide micron distance measurements even for weak (single photons) and short (femtosecond) optical signals. The optical correlator uses a low-noise-integrating detector that can resolve photon number. The correlation (range as a function of path delay) is calculated from the variance of the photon number of the difference of the optical signals on the two detectors. Our preliminary proof-of principle data (using a short-pulse diode laser transmitter) demonstrates tens of microns precision.
    Keywords: Communications and Radar
    Type: GSFC-E-DAA-TN31163 , SPIE Photonics West; Feb 13, 2016 - Feb 18, 2016; San Francisco, CA; United States
    Format: application/pdf
    Location Call Number Expected Availability
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    NASA TECHNICAL REPORTS
  • 5
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    Femtosecond Photon-Counting Receiver (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: An optical correlation receiver is described that provides ultra-precise distance and/or time/pulse-width measurements even for weak (single photons) and short (femtosecond) optical signals. A new type of optical correlation receiver uses a fourth-order (intensity) interferometer to provide micron distance measurements even for weak (single photons) and short (femtosecond) optical signals. The optical correlator uses a low-noise-integrating detector that can resolve photon number. The correlation (range as a function of path delay) is calculated from the variance of the photon number of the difference of the optical signals on the two detectors. Our preliminary proof-of principle data (using a short-pulse diode laser transmitter) demonstrates tens of microns precision.
    Keywords: Communications and Radar
    Type: GSFC-E-DAA-TN31099 , SPIE Photonics West; Feb 13, 2016 - Feb 18, 2016; San Francisco, CA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
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    Ultrasound Based Method and Apparatus for Stone Detection and to Facilitate Clearance Thereof (2015)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Described herein are methods and apparatus for detecting stones by ultrasound, in which the ultrasound reflections from a stone are preferentially selected and accentuated relative to the ultrasound reflections from blood or tissue. Also described herein are methods and apparatus for applying pushing ultrasound to in vivo stones or other objects, to facilitate the removal of such in vivo objects.
    Keywords: Aerospace Medicine
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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