LLCD will be the first high-rate space laser communications system - - PowerPoint PPT Presentation

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llcd will be the first high rate space laser
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LLCD will be the first high-rate space laser communications system - - PowerPoint PPT Presentation

Nov 28, 2023 176 likes •566 views

LLCD will be the first high-rate space laser communications system that can be operated over a range ten times larger than the near-Earth ranges that have been demonstrated to date. from http://esc.gsfc.nasa.gov/267/271.html, enabled by

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“LLCD will be the first high-rate space laser communications system that can be operated over a range ten times larger than the near-Earth ranges that have been demonstrated to date.” from http://esc.gsfc.nasa.gov/267/271.html, enabled by nanowire detectors developed at MIT Lincoln Laboratory in collaboration with MIT campus.

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15-06-12-washington-italy-meeting4

snspd Collaboration between BU, DCG Systems, IBM, Photonspot, funded by IARPA

Image courtesy of DCG Systems

⦿ VLSI circuit

imaging and debugging

⦿ SNSPD

enables performance advances

VLSI Circuit Evaluation

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2016-03-30-vancouver-ubc-5

Characteristics of Photon Detectors

  • Efficiency
  • Reset time
  • Jitter
  • Dark count rate

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time hν incident photons with no signal time incident photons blocked by earlier signal time t1 t3 varying delay between photons and signals voltage time voltage pulses with no corresponding photon t2

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Niobium nitride

4 nm < 100 nm

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R T

critical temperature, Tc resistive superconducting

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I V

critical current, Ic resistive superconducting bias point

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DETECT.SNSPD

Calandri et al., Appl. Phys. Lett., 109 (15) 152601( 2016). Korzh et al., 1804.06839

With JPL and NIST

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  • l/2

l/2

t0 x

ħω

t0 t1 t2

  • l/2

l/2 Position on wire Ch1 Ch2

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DETECT.SNSPD

  • ~ 5nm thick NbN

SiO2 Si 300 nm CPW, 300 nm center conductor width, 3µm gap, SiO2 on Si substrate Signal speed ~2%c

Zhao et al. Nat. Photonics 11, 247 (2017)

Microstrip, 300 nm width AlN on Al2O3 substrate Signal speed 1.6%c

Zhu et al. Nat. Nanotech. 13, 596 (2018)

SiO2 Au Si NbN Si SiO2 CPW with top ground, 200 nm width, 1µm gap, 450 nm spacer, SOI substrate Signal speed 0.87%c

Zhu et al. (2018), unpublished

The group velocity can be further reduced by using high-index dielectric materials A typical nanowire transmission line In collaboration with Daniel Santavicca (UNF)

SiO2 Au Al2O3 AlN NbN 450 nm

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μ μ

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Two connectors for one imager (>500 pixels)

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time (ns) voltage (V) 16 two photon detection events 16 two-photon firing events among 50,000 photon detection events (flood illumination over the entire area)

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75 nm

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Large-area WSi SNSPD

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Robert Lasenby Stanford

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  • Angle Velasco (JPL)
  • Andrew Beyer (JPL)
  • Jason Allmaras (JPL)
  • Edward Ramirez (JPL)
  • Brian Noble (UNF)
  • William Strickland (UNF)
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taper taper 14 mm 3 mm 1 mm The first transmitted pulses

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μ μ

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μ μ

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μ μ