Researchers from the NRC and the University of Málaga have developed new technology that could be used in future networks to provide internet service to Canada's rural and remote communities. By placing photonic (light-manipulating) components onto microchips, laser beams could soon be used to deliver secure, high-speed internet anywhere. The team also used nanotechnology (extremely small materials) to create specialized devices that allow these systems to use less power.
Since we first heard the command, "Beam us up!" in the 20th-century TV series Star Trek, we've been fascinated by futuristic technologies that perform amazing feats. One such technology—at the time, fictional laser devices—captivated the world. Their beams could control and manoeuver objects, trigger explosions or stun enemies, and blast through walls and people.
Today, laser beams are used in countless benevolent applications, both in space and on Earth. These include self-driving cars, healthcare microscopy, cellphones and satellite communications.
In next-generation space-based communications systems, the beams will carry data to help thousands of satellites communicate efficiently with each other, deep space and Earth. Since the satellites soar around the globe at high speeds, the bouncing beams must be constantly redirected to keep data moving toward the eventual targets. To do that effectively is quite an engineering challenge, as commercial applications demand ever faster, smaller and more efficient devices.
Laser beams in free space have typically been steered by bulky mirrors using precision mechanics. But for outer space application, the curved mirrors do not provide the required robustness, speed, cost-effectiveness, accuracy or longevity.
Over the past 3 years, researchers at the National Research Council of Canada (NRC) have developed an inexpensive alternative using lightweight optoelectronic silicon microchips such as those found in electronics. "Unlike mirrors, the chips do not move and weigh only fractions of a gram," says Dr. Jens Schmid, Team Leader of Nanophotonics at the Advanced Electronics and Photonics (AEP) Research Centre. "Chip-based beam steering technology uses optical phased arrays, which require complex electronic control of a large number of optical emitters arranged on a chip."
Collaborations steer research
In collaboration with the University of Málaga in Spain and Carleton University in Ottawa, and supported by the High-throughput and Secure Networks (HTSN) Challenge program, the NRC team working with Dr. Pavel Cheben and Dr. Schmid addressed huge challenges specific to integrated photonics. For example, they mastered the concept of implementing large-aperture light emitters directly onto a photonic integrated chip.
One groundbreaking antenna design showed that standard silicon photonic fabrication techniques could be used to create very long antennas (2 mm) emitting low divergence beams (0.1 degrees far field divergence).
"Our team also invented nanostructured metamaterial waveguides which, in conjunction with a very compact optical feeder element, reduce the power consumption and complexity of electronic controls," adds Dr. Schmid. "We demonstrated a practical way to scale up the size of silicon chip-based beam steering antenna arrays that emit a more collimated beam, increasing the range of the device."
He points out that collaborations are invaluable to complement expertise at the NRC. With help from senior scientists at both universities, the project work has resulted in 3 peer-reviewed publications in the last 3 years, including an article in the July 2022 issue of Laser and Photonics Reviews.
"Our PhD student from Spain, Pablo Ginel-Moreno, was also able to spend time at the NRC under our direct supervision," he says. "He went on to win awards at the 2021 IEEE Group IV Photonics conference and the 2022 ePIXfab Silicon Photonics Summer School in Paris."
For the experimental demonstration of the new concept, the NRC contracted Edmonton, Alberta-based Applied Nanotools Inc. to produce the nanofabricated silicon chips, using the NanoSOI photonics fabrication service.
The next phase of this project will involve working with Carleton University to build a functioning beam-steering system with optical antennas, as well as to devise innovations for performance improvements that include massive increases in wireless data rate.
"Such collaborations prove that working with people who add expertise and training to our internal multidisciplinary teams can propel us all to the forefront of a research field," adds Dr. Schmid. "We have also been able to generate valuable IP on our new approaches in this area of rapidly growing commercial interest."
Beaming light toward the future
The NRC's advances in optical antennas and arrays design can increase the capacity of low Earth orbit (LEO) satellite constellations and their complementary ground infrastructure. They can also be adapted for applications such as Light Detection and Ranging (LiDAR), which uses lasers to map out the surroundings of self-driving vehicles.
The initial intent of the NRC's invention is to help Canada's rural and remote communities through the NRC's High-throughput and Secure Networks (HTSN) Challenge program. The game-changing technology, which replaces fibre networks with laser beams, can be used to offer secure high-speed internet anywhere.
"In many parts of our vast northern regions, for example, laying optical fibres underground is not cost-effective," says Dr. Schmid. "With laser beams, we could upload the data from big cities in the south and hand the beams off to various satellites until they reach their targets, without ever touching the ground."
This technology is in high demand because free-space optical communications hold great promise for meeting rapidly evolving future needs. "With a focus on this research, we and our collaborators are well on our way to conquering new frontiers," concludes Dr. Schmid.