R&D on Space Laser Communications Technology
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Optical Amplifier

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NICT successfully conducts experiments for free-space optical communications between LEO satellites and optical ground stations, while researching and studying fundamental technologies for future space optical communications such as the following:

 

  • Optical receivers

  • Transportable optical ground stations

  • Optical amplifiers for space

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Optical Receiver(Intradyne Optical Coherent Method)
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Optical coherent methods are one of the main topics of interest in the study of fiber optic communications. Based on high-speed digital processing, the coherent method enables the same functions as the Optical PLL (Phase-Locked Loop).


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Transportable Optical Ground Station
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Elimination of the effects of weather or atmospheric conditions is an important factor for the optical link between space and the ground.

 

We are researching the possibility of site diversity by placing several ground stations in different locations. We aim to establish a space-ground optical link using transportable telescopes and ground networks.

 

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Fine Pointing Mechanism
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We are developing a fine pointing mechanism to couple a laser with fiber optics on the ground.

 

 

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Microwave Environment Transport
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People use various kinds of electromagnetic signals in their daily lives. In addition to common examples such as televisions, radios, and cellphones, recent wireless LANs and game devices also use radio signals.


If microwave environment transport technologies are appropriately applied in daily life, the current situation in which users or terminals must adapt to the microwave environment would shift to a situation in which users or terminals could use the technologies comfortably without noticing that they are using them.

 

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Space Quantum Cryptographic Communication
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Quantum key distribution technologies are said to be limited to 300 km for fiber optic data transmissions, due to attenuation or noise. However, if satellites are used, the distance could be increased, enabling global quantum key distribution throughout the whole world.


NICT is working on the development of optical terminals that implement space quantum cryptographic communication and space-fiber conversion technologies for quantum entanglement.

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Optical Communication Device with a Laser Array
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Traditional configurations of optical communication devices tend to add volume, mass, and power, for example, several kilograms, due the movable mechanical parts on telescopes or mirrors for tracking optical beams. Laser communication devices must be reduced in size in order to become more convenient and useful. NICT has developed a multiple-input/multiple-output laser communication device that can track multiple targets at the same time by eliminating mechanical movable parts and deploying lasers in arrays instead.

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Laser Transmission through Atmospheric Distortion
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Laser communications between satellites and optical ground stations require the satellites to continuously send laser beams back to Earth while moving very quickly, without being affected by atmospheric distortion. This is a difficult challenge, and advanced technologies are essential. Laser communication experiments with LEO satellites, which move very quickly in comparison with geosynchronous satellites, require more sophisticated technology to acquire and track the satellites.


Please refer to previous examples of LEO-to-earth and GEO-to-earth laser communication experiments.

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Laser Ranging Technology
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SLR (Satellite Laser Ranging) is a space geodetic technology that measures the distance between a ground station and a satellite. Because of its precision and accuracy, this technology is used for satellite orbit determination and areas of research such as crustal movement observation, the earth's gravitational field, and atmosphere-ocean dynamics. Measurement values obtained from SLR are based on the dynamic movements of the satellite orbiting the center of gravity of the Earth. This is in contrast to VLBI measurements, which make geometrical measurements based on the location of quasi-stellar objects at infinite distance.

→ to SLR page

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