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Design and performance of a 40W uplink laser transmitter for NASA's O2O laser communications mission

January 14, 2025
  |
Conference Paper
Author:
Katia Shtyrkova
…
Topic:
laser communications
R&D group:

Summary

NASA's Orion Artemis II Optical Communications System (O2O) will provide operational laser communications between the ground and lunar orbit for the Artemis II crewed mission. In this work we describe a 40 W ground-based laser transmitter for the O2O system. The uplink transmitter operates in the optical C-band and uses an energy-efficient 32- PPM modulation format. Four spatial diversity channels are time-aligned and combined in the far field. Each channel produces up to 10 W of output power and contains both the communications signal and the 7 kHz modulated beacon signal required for acquisition. The transmitter delivers data at 10 Mbits/s and 20 Mbits/s channel rates, corresponding to the 250 MHz and 500 MHz slot rates respectively.
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Summary

NASA's Orion Artemis II Optical Communications System (O2O) will provide operational laser communications between the ground and lunar orbit for the Artemis II crewed mission. In this work we describe a 40 W ground-based laser transmitter for the O2O system. The uplink transmitter operates in the optical C-band and uses...

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Design and performance of a 40W uplink laser transmitter for NASA's O2O laser communications mission

Effect of carrier lifetime on forward-biased silicon Mach-Zehnder modulators

April 14, 2008
  |
Journal Article
Author:
Gui-Rong Zhou
…
Published in:
Opt. Express, Vol. 16, No. 8, 14 April 2008, pp. 5218-5226.
Topic:
optics
R&D area:
R&D group:

Summary

We present a systematic study of Mach-Zehnder silicon optical modulators based on carrier-injection. Detailed comparisons between modeling and measurement results are made with good agreement obtained for both DC and AC characteristics. A figure of merit, static VpiL, as low as 0.24Vmm is achieved. The effect of carrier lifetime variation with doping concentration is explored and found to be important for the modulator characteristics.
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Summary

We present a systematic study of Mach-Zehnder silicon optical modulators based on carrier-injection. Detailed comparisons between modeling and measurement results are made with good agreement obtained for both DC and AC characteristics. A figure of merit, static VpiL, as low as 0.24Vmm is achieved. The effect of carrier lifetime variation...

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Effect of carrier lifetime on forward-biased silicon Mach-Zehnder modulators

All silicon infrared photodiodes: photo response and effects of processing temperature

December 10, 2007
  |
Journal Article
Author:
Michael W. Geis
…
Published in:
Opt. Express, Vol. 15, No. 25, 10 December 2007, 87083.
Topic:
optics
R&D area:
R&D group:

Summary

CMOS compatible infrared waveguide Si photodiodes are made responsive from 1100 to 1750 nm by Si+ implantation and annealing. This article compares diodes fabricated using two annealing temperatures, 300 and 475C. 0.25-mm-long diodes annealed to 300C have a response to 1539 nm radiation of 0.1 A W-1 at a reverse bias of 5 V and 1.2 A W-1 at 20 V. 3-mm-long diodes processed to 475C exhibited two states, L1 and L2, with photo responses of 0.3 +/-0.1 A W-1 at 5 V and 0.7 +/-10.2 A W-1 at 20 V for the L1 state and 0.5 +/-0.2 A W-1 at 5 V and 4 to 20 A W-1 at 20 V for the L2 state. The diodes can be switched between L1 and L2. The bandwidths vary from 10 to 20 GHz. These diodes will generate electrical power from the incident radiation with efficiencies from 4 to 10 %.
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Summary

CMOS compatible infrared waveguide Si photodiodes are made responsive from 1100 to 1750 nm by Si+ implantation and annealing. This article compares diodes fabricated using two annealing temperatures, 300 and 475C. 0.25-mm-long diodes annealed to 300C have a response to 1539 nm radiation of 0.1 A W-1 at a reverse...

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All silicon infrared photodiodes: photo response and effects of processing temperature
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