NASA preps silicon-photonic modem for space laser internet test

Aeronautical agency will offer its small, speedy LCRD tech to industry

NASA's preparing the next step of its lasers-in-space optical communications strategy, announcing the development of a silicon photonic modem for space applications.

The agency's engineering team is getting ready to build the modem, which integrates electrical and optical signalling and processing on a single chip.

The news comes hard on the heels of the European Space Agency's launch of a full-time in-space optical communications system, the European Data Relay System, which the agency is pleased to report has resulted in the first satellite settling in its desired orbit.1

Both NASA and the ESA (European Space Agency) want optical communications in space for the obvious reason: you get more bandwidth than is available from radio communications. NASA hopes for gigabit or better speeds from the silicon photonics technology.

NASA's integrated photonics modem, which the agency describes as the first to be designed for use in space, won't get to sling photons in anger until 2020, when its first test aboard the International Space Station (ISS) is planned.

Dubbed LCRD (Laser Communications Relay Demonstration), the chip integrates what would otherwise be standalone optical equipment on-chip, alongside the electronics. That, NASA says, gets a considerable reduction in size and weight, compared to optical terminals the size of "two toaster ovens."

For its ISS tests, the chip will form part of the Integrated LCRD LEO (low-earth orbit) User Modem and Amplifier (ILLUMA).

The ESA's recent test demonstrated space-to-space optical communications, but ILLUMA will be a space-to-Earth communications system like NASA's previous optical demonstration, a 622 Mbps-down, 20 Mbps-up payload on its LADEE lunar probe.

After low-Earth orbit tests, NASA plans to spend two years getting the system communicating from geosynchronous orbit, and later, as a geosynchronous-to-LEO relay system.

The agency hopes there'll be broader payoffs for industry. It explains that integrated silicon photonics have developed to the point where the devices can be "lithographically printed in mass ... driving down the costs of photonic devices."

"It is clear that our strategy to leverage integrated photonic circuitry will lead to a revolution in Earth and planetary-space communications as well as in science instruments," NASA's press release says.

The agency intends to make the technology available to industry and other government agencies, which should help drive down costs further. ®