by Robert Schreiber
Berlin, Germany (SPX) Sep 11, 2024
Researchers have successfully achieved data transmission rates of up to 424 Gbit/s across a 53-km free-space optical link using plasmonic modulators, which control optical signals through surface plasmon polaritons. This advancement paves the way for high-speed optical communication links that can transmit data through open air or space.
Free-space optical communication networks offer significant advantages for space exploration by providing high-capacity, high-speed data transfer with lower latency and reduced interference compared to traditional radio frequency systems. These networks could lead to more efficient data transfer, improved connectivity, and enhanced functionality for space missions.
Laurenz Kulmer, a member of the Leuthold group at ETH Zurich, will present these findings at the upcoming Frontiers in Optics + Laser Science (FiO LS) conference, scheduled to take place from September 23-26, 2024, at the Colorado Convention Center in Denver.
"High-speed free-space transmission is an option to connect the world, or it may serve as a backup if underwater cables break," said Kulmer. "Nevertheless, it is also a step towards a new cheap high-speed internet that may connect all locations across the world. This way it may contribute towards a stable, high-speed internet for millions of people who are currently unconnected."
Plasmonic modulators are particularly well-suited for space communication due to their compact design, ability to operate at high speeds, wide temperature range tolerance, and low energy consumption.
In outdoor free-space optical tests, the researchers achieved data rates of up to 424 Gbit/s while staying under a 25% SD FEC threshold-indicating that despite interference, the system could still correct errors in the transmitted data. Furthermore, tests using a plasmonic IQ modulator within a fiber system achieved a higher throughput of up to 774 Gbit/s per polarization, remaining below the same error-correction threshold.
These results suggest that combining plasmonic modulators with coherent free-space optical communication could lead to further increases in data throughput, potentially reaching speeds of 1.4 Tbit/s. The findings also indicate that it is more advantageous to operate at the highest speeds in free-space optical links, rather than utilizing higher-order modulation formats at lower speeds. The researchers believe that further improvements in device design and photonic integration could enable polarization multiplexing data rates exceeding 1 Tbit/s per polarization channel.
"In a next step we are going to test the long-term reliability of our devices," added Kulmer. "High-speed performance has been shown, but we have to make sure they can operate for years to come in the harshest of environments, space."
Frontiers in Optics, the annual meeting for Optica, is presented alongside Laser Science, the annual meeting of the American Physical Society's Division of Laser Science. Together, these events bring together research communities from both societies, covering a broad range of topics across optics, photonics, and related scientific disciplines. The 2024 FiO LS Conference will feature hundreds of live contributed and invited talks. More information can be found at https://www.frontiersinoptics.com.
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