2025-12-29 22:00:02
Powering the AI data center boom dominated the conversation in the global energy sector in 2025. Governments are racing to develop the most advanced AI models, and data center developers are building as fast as they can. But no one is going to get very far without finding ways to generate and move more electricity to these power guzzlers.
Spectrum’s most popular energy stories in 2025 centered around that theme. Readers were particularly interested in stories about next-generation nuclear power, such as small modular reactors and salt-cooled reactors, and how those technologies might support data centers. Readers also turned to Spectrum to learn about the strain all of this is putting on electricity grids, and new technologies to solve those problems.
Despite the weightiness of the energy sector’s challenges, we found some fun, off-beat stories to tell too. One American company is building the world’s largest airplane—it’s bigger than a football field—and it will have one job: to transport wind turbine blades.
I don’t know what 2026 will bring, but as Spectrum’s energy editor, I’ll do my best to provide you stories that are true, useful, and engaging. Cheers to a new year in energy!
GE Vernova
The world suddenly needs more power, but one solution being tested is to downsize energy generation and distribute it more widely. One example of that is small modular reactors (SMRs). These nuclear fission reactors are less than a third of the size and power output of conventional reactors. And as the April deadline approached for applying for the US $900 million the United States was offering for SMR development, readers came to Spectrum in droves to learn about the program in a news article authored by contributor Shannon Cuthrell.
But the SMR money paled in comparison to the $80 billion that the United States is spending on a fleet of large-scale nuclear reactors designed by Westinghouse. Will this next group of reactors suffer from the same delays and cost overruns as the ones that put Westinghouse into bankruptcy just a few years ago? Spectrum brought readers an expert analysis on the subject by Wood MacKenzie’s Ed Crooks.
Edmon de Haro
The United States may have the most SMRs in development, but China has the one that’s furthest along. The Linglong One, on the island of Hainan, is expected to begin operations in the first half of 2026. And that’s just one component in a smorgasbord of nuclear reactor experimentation in China. One of the country’s most interesting projects is a thorium-powered, molten-salt reactor, which it began building in 2025 in the Gobi desert. Prior to this project, the last operating molten-salt reactor was at Oak Ridge National Laboratory, which shut down in 1969.
The attraction of thorium as a fuel is that it reduces dependence on uranium. Very little information is available on the progress of China’s thorium reactor, but with help from our Taiwan-based freelancer Yu-Tzu Chiu, we know it’s small—only 10 megawatts—and is scheduled to be operational by 2030. Check back with Spectrum for updates on this reactor and the Linglong One.
Radia
While nuclear reactors need to get smaller, wind turbines need to get bigger, say some renewable energy advocates. And the biggest obstacle to bigger wind—besides the present political backlash—is transportation. Roads, bridges, and train tracks dictate the size of on-shore wind turbine blades, and usually can’t accommodate anything over 70 meters long. That’s why Radia, an aviation startup in Boulder, Colo., is building the world’s largest airplane. It will stretch 108 meters in length, be shaped to hold a 105-meter blade, and can land on a makeshift dirt runway. Spectrum contributor Andrew Moseman traveled to Radia’s headquarters to check out the aircraft’s design and fly the behemoth on the company’s simulator. (Spoiler: He landed it.)
National Grid Electricity Transmission/Smart Wires
None of this new energy generation will matter if we can’t move it across the grid to customers who need it. But many key transmission corridors are maxed. Blackouts are growing longer and more common. Building new transmission lines takes years and often gets thwarted by NIMBY pushback. Queues for connecting to the grid, whether you’re providing power or requesting it, can be comically long.
To bridge the gap, grid operators globally are turning to innovative grid tech. Collectively called grid-enhancing technologies (GETs), some of the boldest examples can be found in the United Kingdom. For example, the U.K.’s National Grid has been implementing electronic power-flow controllers, called SmartValves, that shift electricity from jammed circuits to those with spare capacity.
The U.K. and other countries have also been reconductoring old lines and installing dynamic line rating, which calculates how much current high-voltage lines can safely carry based on real-time weather conditions. And Scotland has been beefing up its grid-scale battery stations with advanced converters. These leap into action within milliseconds to release the extra power needed when energy supply elsewhere on the grid falters. Spectrum contributor Peter Fairley, who authored several of these stories, traveled to the U.K. to investigate grid congestion woes and tech solutions.
Yamil Lage/AFP/Getty Images
At the opposite end of the spectrum, one of the world’s most neglected grids can be found in Cuba. There, decades of poor fuel and maintenance have left the country’s energy infrastructure in crisis. Lately, Cuba’s entire grid has been collapsing every couple of months. Blackouts are so common that citizens are cooking multiple meals at once and working by flashlight, says Ricardo Torres, a Cuban economist who explained the situation for Spectrum readers in this popular expert-authored guest post.
The nearby Caribbean island of Puerto Rico has also been enduring more frequent blackouts, leading some to speculate that the grid in this American territory may go the same way as Cuba’s. The turmoil has prompted widespread development of solar-plus-storage systems across the island that are privately financed, reports Spectrum contributor Julia Tilton.
Edmon de Haro
On the lighter side, we also explored the world of nuclear batteries. These devices store energy in the form of radioactive isotopes. They can last for decades, making them ideal for medical implants, remote infrastructure, robots, and sensors. But the allure of a small battery with a 50-year lifespan has given this sector several false starts. There was a stint in the 1970s where surgeons implanted nuclear-powered pacemakers in over 1,400 people only to lose track of them over time. Regulators balked when devices containing plutonium-238 started turning up in crematoriums and coffins.
Now the field is experiencing a resurgence in interest. Companies on multiple continents are claiming to be on the verge of commercialization of nuclear batteries. Whether they’ll find willing markets is unclear. In a feature for Spectrum, nuclear battery expert James Blanchard details the history of these devices and why there’s suddenly more activity in this field than he’s ever seen in his 40-year career.
Brittany Greeson
Sometimes a story is so good that we just have to publish it, even if we find it somewhere else. That was the case with a chapter from the book Inevitable: Inside the Messy, Unstoppable Transition to Electric Vehicles (Harvard Business Review Press, 2025). The chapter tells the tale of one power-train engineer at Ford whose internal-combustion-engine expertise slowly became expendable as car companies pivoted to EVs. With permission, we published an adapted version of the chapter, which is chock-full of excellent reporting from author Mike Colias, a veteran automotive reporter. Don’t miss it! (Spoiler: The engineer, Lem Yeung, who left Ford after 30 years, ended up returning to the company a few years later to help clean up the mess caused by the loss of old-school talent. We caught up with Yeung after his return in this Q&A.)
2025-12-29 21:00:02
Christina had tried dieting and exercise before. The weight always came off but then crept back on, especially after she gave birth to her son in 2022.
She had hoped that a new class of weight-loss drugs might finally offer something different. Obesity treatments such as Wegovy and Zepbound had just arrived on the scene, helping people slim down with unprecedented ease. But the price tag of these GLP-1 drugs put them out of reach. Christina’s health insurance wouldn’t cover the cost.
Desperate for another option, Christina enrolled in a clinical trial that guaranteed several months on a blockbuster weight-loss therapy—and then the possibility of something more. (Christina, a Texas woman in her early 50s, asked that her last name be withheld to protect her privacy about her weight-loss treatment.)
That something more wasn’t another injection or pill, but a one-time procedure using a new medical device. And instead of targeting the stomach or brain, it focused on the gut itself: rewiring how a part of the upper intestine, known as the duodenum, processes nutrients and regulates metabolism.
Performed via a minimally invasive endoscopic device, this approach is designed to help people who want to stop taking GLP-1 drugs. The goal is to lock in the benefits without the high costs, weekly jabs, or lingering side effects. And in 2026, the first company to develop such a device is likely to seek clearance to bring it to patients.
“We’re creating a new therapeutic area,” says Harith Rajagopalan, cofounder and chief executive of that company, Fractyl Health, based in Burlington, Mass.
You can think of these systems as a middle ground between drugs and bariatric surgery. The endoscope is a slim, flexible tube equipped with a camera and a guidewire that leads a catheter into the digestive system. Doctors send the tools down the throat so they can view and modify the intestines from the inside—remodeling gut tissue and recalibrating its response to food without a single incision. The procedure takes about an hour or so, and patients typically go home the same day.
To understand how the treatment works, it helps to first understand what goes wrong in the gut during years of unhealthy eating. As diets high in sugar and fat bombard the duodenum, the lining there becomes inflamed and its normal signaling pathways distorted. Mucosal cells in the tissue grow abnormally and propagate these maladaptive changes, locking in a dysfunctional pattern that drives cravings, weight gain, and insulin resistance.
The Fractyl device overcomes these entrenched changes. It works by deliberately injuring the tissue, using near-boiling water to burn off diseased cells on the intestinal lining. A natural healing process then kicks in, producing a fresh layer of healthy tissue and re-establishing proper metabolic control.
“You see regrowth at about two weeks, and it continues until the mucosa looks pretty normal,” says Alan Cherrington, a physiologist at Vanderbilt University School of Medicine who consults for Fractyl.
Preliminary results from the clinical trial that Christina joined, termed the Remain-1 study, indicate that the procedure is working as intended to stabilize weight after GLP-1 therapy. Three months after stopping Zepbound, study participants who underwent the Fractyl procedure generally held their weight steady or continued to lose weight, while those who received a sham treatment saw the number on their scales climb steadily upward.
The results are “honestly better than I thought they were going to be,” says one of the doctors leading the trial, Shelby Sullivan, a gastroenterologist and obesity-medicine specialist at the Dartmouth Hitchcock Medical Center in Lebanon, N.H.
Sullivan cautions against drawing firm conclusions, given the small number of participants and short follow-up so far. But anyone watching the field won’t have to wait long for clearer answers. “By six months,” she says, “we absolutely will know if it’s working or not.”
If the six-month data demonstrate lasting weight maintenance—full trial readouts are expected in 2026—Fractyl then intends to seek regulatory clearance to market what could become the first device specifically sanctioned for post-GLP-1 weight control.
But Fractyl is hardly alone in pursuing this therapeutic frontier. Endogenex, a company based in Plymouth, Minn., is using a flexible, expandable circuit board to apply pulsed electric fields directly to the duodenal wall to burn away the problem cells. Meanwhile, TeCure, in South Korea, and Aqua Medical, in Pleasanton, Calif., are using lasers and radiofrequency-heated water vapor, respectively, to achieve a similar remodeling of the gut lining.
“In the end, it’s different methods to do the same thing,” says Pichamol Jirapinyo, a bariatric endoscopist at Brigham and Women’s Hospital in Boston and a cofounder of Bariendo, a network of 10 nonsurgical weight-loss clinics across the United States. While ongoing trials may clarify differences in efficacy and safety, Jirapinyo (who consults for Fractyl) expects operational features such as ease of use and procedure time to play a decisive role in determining uptake among practitioners.
Timing of market entry is critical, too—and Fractyl, now leading the pack, is expected to deliver the first large-scale clinical results. Those outcomes, from the trial that Sullivan is leading, could set the tone for an entire class of new device-based obesity treatments aiming to preserve the gains of GLP-1 drugs, notes Endogenex CEO Stacey Pugh. “If they are successful, it’s going to blow this field wide open,” she says.
Not everyone is convinced that resurfacing the duodenum is the way to go. In Europe, the past year saw the arrival of a new weight-loss device called Reset that—while not explicitly authorized for use in a post-GLP-1 drug setting—introduces a sleevelike liner to the duodenum that physically prevents contact between food and the gut wall. That device must be removed within a year, however, offering only a temporary fix.
Other endoscopic approaches target the stomach: One in common use today applies sutures to fold the stomach and shrink its size, while another, more experimental method burns off stomach tissue that regulates the secretion of appetite-stimulating hormones.
These stomach-directed methods may offer a logistical advantage given the relative robustness and accessibility of the stomach, explains Andrew Storm, a therapeutic endoscopist at Wake Forest University in Winston-Salem, N.C. “The duodenum is paper thin, as compared to the stomach, which is like a thick neoprene bag,” he says.
Regulatory clearance for Fractyl would allow the company to directly promote its product for post-GLP-1 weight maintenance—something that Boston Scientific, maker of the most widely used stomach-suturing device, is not legally permitted to do unless it engages in a new round of clinical trials. And that distinction could give duodenal therapies an edge in marketing. But Storm, who consults for Boston Scientific and has also participated in trials of the Endogenex system, raises concerns about the complexity of duodenal therapy. “It just introduces a whole other level of difficulty for the endoscopist that that I think will impact scalability,” he says.
For patients like Christina, the debate over stomach versus duodenum, or one company’s device versus another’s, is largely academic. What matters for her is that the 50 pounds she lost on Zepbound—nearly 20 percent of her body weight—has stayed off so far, a stability that she attributes to the Fractyl device. Because the trial is randomized and blinded, it is possible she actually received the sham procedure. But Christina is fairly confident that she got the real thing.
Her reasoning comes from small but telling moments, like when her husband was cooking smoked pork burnt ends, sending up the kind of rich aromas that once would have sent her straight to the table. “It smelled really good, but I didn’t have any desire to chow down on it,” Christina says.
Experiences like Christina’s hint at the tantalizing promise of a lasting solution after drug-assisted weight loss, but medical-device development demands more than anecdotes. With pivotal trial readouts on the horizon, the year ahead could determine whether these devices remain hopeful prototypes or become validated tools in the next era of obesity care.
2025-12-28 22:00:01
The skies may have rained on this year’s big climate summit in Belém, Brazil, but engineers have invented plenty of exciting climate tech this year worth celebrating. Here are some of the year’s top IEEE Spectrum climate technology stories:
Richard Zare, Xiaowei Song et al.
Ammonia is a crucial ingredient for human civilization, powering agriculture, explosives, and next-generation cargo ships. Researchers have turned to classical laboratory chemistry and artificial intelligence in search of more efficient ammonia production. In January, freelance contributor Alfred Poor reported on a real-world demonstration of a passive technology that captures ammonia from the wind, no batteries included or needed.
Daniel Kunz
At IEEE Spectrum, we love any story that puts electrons to good use, and freelance contributor Rachel Berkowitz found a startup using piezoelectric catalysts to zap forever chemicals that contaminate our waterways. Most systems spend a lot of energy mechanically filtering out the harmful, long-lasting chemicals, but these researchers propose to use the kinetic energy of natural water flow to drive their system, along with their clever chemical harnessing of electrons. Take that mechanical engineers! And forever chemicals, of course.
Original photo: Emily Waltz
Thought that the only greenhouse gas you had to worry about was carbon dioxide? Beware: Some fluoride-related gases have heat-trapping abilities thousands of time greater than CO2. One in particular, SF6, happens to be the main insulator in high-voltage circuit breakers necessary all across our electrical grids. Energy editor Emily Waltz had the story on how to use supercritical CO2 gas instead, keeping toxic SF6—responsible for about 1 percent of global warming in 2018--out of our supply chain and atmosphere.
Chris Philpot
It’s one thing to prevent emitting greenhouse gases into the atmosphere and quite another to trap carbon from the air. Longtime contributing editor W. Wayt Gibbs dove into the question of just how much carbon society might remove from the atmosphere for The Scale Issue. The resulting infographic identifies places we can inject CO2 underground, how much people have managed to capture so far, and the scale of the remaining challenge.
Hannibal Hanschke/Reuters/Redux
It will take more than engineering to mine Greenland’s rare earth elements, which are valuable for many types of climate technology, wrote mining consultant and former deputy director of the Geological Survey of Denmark and Greenland Flemming Getreuer Christiansen in a guest article: It will take political clarity now lacking. Like so many other exciting engineering problems, politics are the limiting factor.
Nicole Millman; Original art: Daria Ustiugova
And finally, because IEEE Spectrum readers know we should balance the technical side of our lives with poetry, a meditation by fiber-optic engineer and poet Steven Searcy on the joys and electrons of summer.
2025-12-28 21:00:02
Ten years ago, ride-sharing giant Uber embraced a sci-fi future in which clean, quiet electric aircraft would shuttle passengers around crowded cities. Uber’s well-funded Elevate initiative, which included a white paper and three high-profile annual summits, effectively launched the electric vertical take-off and landing (eVTOL) industry, promising investors, regulators, and the general public that these futuristic flying taxis were “closer than you think.”
At the time, California-based Joby Aviation was still in stealth mode. But behind the scenes, this pioneering eVTOL developer—which has received more than US $3 billion in total funding, including around $900 million from Toyota—was playing a major role in shaping Uber’s vision. It later stepped in to keep that vision alive, acquiring the Elevate program in 2020 after Uber CEO Dara Khosrowshahi decided to axe it.
Now, Joby, which was founded in 2009 and has become the dominant eVTOL startup, says it is finally on the verge of making “urban air mobility” a reality. It plans to conduct its first passenger flights in 2026 in Dubai, United Arab Emirates.
“Dubai continues to be our global launchpad for commercial service, and our progress here is a testament to the UAE’s visionary approach to advanced air mobility,” says Anthony Khoury, Joby’s UAE general manager, in an email interview. “Dubai is on track to be the first city in the world to offer a fully integrated, premium air taxi network, and we are sprinting toward that target.”
The company first announced its UAE plans at the World Governments Summit in Dubai in February 2024, striking a deal with Dubai’s Roads and Transport Authority (RTA) that gives it an exclusive right to operate air taxis there for six years from the launch of commercial operations.
Joby’s exclusive Dubai deal will help fortify its lead in the global race to commercialize electric air taxis
Joby also signed an agreement with U.K.-based Skyports to design, build, and operate four “vertiport” sites in Dubai—places for the eVTOL aircraft to load and unload passengers and charge their batteries. The first vertiport will be near Dubai International Airport, with additional ones planned for Dubai Mall, the Atlantis the Royal resort, and American University in Dubai.
Joby won’t be the first eVTOL developer to carry passengers. That distinction goes to China’s EHang, which is already conducting limited sightseeing and demonstration flights with its two-seat, autonomous electric multicopters. (Joby’s aircraft are piloted.) If Joby pulls off its goal, however, it will be the first to routinely fly passengers from point to point over urban traffic, in keeping with Uber Elevate’s original vision. Its exclusive agreement in Dubai will help fortify its lead in the global race to commercialize electric air taxis, which includes a handful of other Western eVTOL developers, plus a growing number of Chinese players. Besides its Dubai deal, Joby also has a partnership with Delta to start an airport shuttle service in the United States.
The Joby S4 electric vertical takeoff and landing (eVTOL) aircraft has six electric motors, each weighing 28 kilograms and capable of a peak output of 236 kilowatts.Joby Aviation
Operating a reliable air taxi service is a demanding proposition that will require Joby’s aircraft, charging infrastructure, and scheduling software to perform safely and reliably day in and day out. Since every new and complex technology has teething problems, Joby envisions fairly limited initial operations in 2026.
“We will transition from test flights to more complex proving runs and eventually nonpaying passenger flights out of the completed vertiports, ensuring a seamless passenger experience ahead of full commercial launch,” says Khoury. He adds that Joby is currently working with Skyports to ready its initial vertiports and with government agencies in Dubai and the UAE to receive the necessary approvals for its operations.
“Dubai’s approach is deeper and more comprehensive than what you see in many of the headlines,” said Clint Harper, an aviation infrastructure and policy advisor who recently participated in an advanced air mobility workshop with Dubai’s RTA. “In our workshop,” he says, “the RTA staff had fantastic questions and concerns regarding safety, security, and system-level integration. Everyone recognized and appreciated strong government support and wanted to deliver the right system solution, not just a one-off demo. I was thoroughly impressed and inspired.”
Notably, all of this groundwork is taking place in advance of Joby receiving an initial type certificate for its aircraft from the U.S. Federal Aviation Administration. In the United States (and elsewhere), a type certificate is typically a prerequisite for conducting commercial operations with paying passengers. Joby claims it’s making good progress toward FAA certification, but how quickly (or slowly) that process moves is largely out of its hands. In recent years, the FAA has been taking longer to certify even conventional airplanes and helicopters, which the industry blames on staffing shortages at the agency and more cautious decision-making in the wake of the Boeing 737 Max crisis.
This perception that certification delays have more to do with bureaucracy than safety may be why Dubai is willing to approve some early operations by Joby in advance of FAA type certification. Interestingly, the United States is now following the UAE’s example. In September, the FAA and U.S. Department of Transportation began soliciting proposals for an eVTOL Integration Pilot Program (eIPP), which will select at least five projects to demonstrate eVTOL operations in the national airspace starting as early as summer 2026.
The FAA has stated that the eIPP won’t allow eVTOL developers to bypass certification requirements or carry paying passengers. However, it will enable them to undertake additional testing and demonstration flights as a stepping-stone to commercial operations. Joby says it’s planning to take part in the eIPP, meaning its air taxis could also be flying over U.S. cities in 2026—even if the only person on board is the pilot.
2025-12-27 22:00:01
In 2025, many of IEEE Spectrum‘s top consumer electronics stories were about about creating the experience you want with technology. Open-source software offered more customization for laptops and displays, devices with less distracting design received recognition with a new certification, and smart glasses manufacturers forged paths to figure out what users really want in the wearable tech.
Other stories highlighted the fascinating fundamental tech in our smartphones, like how your new iPhone stays cool and the potential for its camera to gather information beyond what the human eye can see. And we considered the effects of U.S. tariffs from the Trump administration.
We’re gearing up for a 2026 filled with many more exciting developments. In the meantime, read on for IEEE Spectrum’s most popular consumer electronic stories of the year.
Source image: Modos
When hours of our days may be dominated by screens, e-paper displays offer an option easier on the eyes. Historically, these displays have been too slow for everyday computing. But this year, a small Boston-based startup called Modos created a monitor and development kit for a display with a refresh rate of 75 hertz—comparable to some basic LCD screens. That’s even fast enough for video.
“Modos has a not-so-secret weapon,” contributing editor Matthew Smith writes. Specifically, an open-source display controller is key to the display’s speed. Modos completed its crowdfunding campaign and pre-orders are scheduled to ship in late January 2026.
IEEE Spectrum; Source images: Apple
Without the proper cooling tech, high-end smartphones risk burning a hole in your pocket—literally. In the latest generation of Apple smartphones, released in September, the iPhone 17 Pro and Pro Max contain thin chambers of water that help dissipate heat through evaporation. Cooling phones with water vapor isn’t entirely new though: High-end smartphones from Samsung and Google also use the technique.
For more on how to keep our electronics cool, check out IEEE Spectrum’s recent special report, The Hot, Hot Future of Chips. Our editors and expert authors break down how lasers, liquid cooling, and diamond blankets could all contribute to thermal management for increasingly complex and capable chips.
DeepComputing
Most laptops can only be customized so much. Once you get down to the level of specific instructions for how the computer executes instructions—the instruction set architecture—laptops usually operate on proprietary technology like x86 and Arm.
Earlier this year, repairable computer maker Framework released a laptop that can support a RISC-V mainboard, bringing open-source architecture to the masses—or at least, developers and early adopters interested in straying from mainstream closed architectures. Later in the year, Framework also made news when it released a swappable laptop graphics module, allowing users to choose between the AMD GPU the laptop originally shipped with and Nvidia’s RTX 5070.
Vincent Walter/Purdue University
A picture is worth a thousand words, as the cliché goes. But the images taken by your smartphone camera contain more information than you might realize. While the human eye is sensitive to a limited range of visible light wavelengths, the pixels in a standard smartphone camera sensor are potentially sensitive to a much wider range of wavelengths.
Researchers at Purdue University developed a way to capture hyperspectral information by placing a card with a color chart in frame. With this technique, an ordinary smartphone could serve as a “pocket spectrometer” and identify specific chemicals for medical diagnostics, analyzing pigments in artwork, and more.
Anthony Behar/Sipa USA/Alamy
Shortly after U.S. President Donald Trump was sworn into office for his second term in January, he began enacting new tariffs on foreign goods. In April, Trump announced significant changes, including a universal 10 percent tariff on all imports, as well as a 125 percent tariff on Chinese goods (now reduced to a much lower 10 percent baseline).
To learn how these tariffs might affect the U.S. electronics market, senior editor Samuel Moore interviewed Shawn DuBravac, chief economist of the Global Electronics Association (formerly IPC, or the Institute of Printed Circuits). Amidst ongoing changes, they spoke about predicted price increases, shifting supply chains, and the effect on lower-priced electronics.
Spectrum also covered how tariffs affect hobbyists and students, who often rely on components sourced from suppliers outside of the United States. And keep an eye out for more stories on the relationship between tech and government from technology policy editor, Lucas Laursen.
Mui Lab
With the sheer quantity of eye-catching tech displayed at the annual Consumer Electronics Show (CES), it’s fitting that the event is hosted in Las Vegas. But at CES 2025, some devices took a different approach. The Calm Tech Institute issued a new certification to several devices shown at CES that are designed to be less distracting and command less of our primary attention.
For instance, an e-ink tablet and a wood-like smart-home interface were among the first batch of devices that received the certification. While everyday devices bombard us with notifications, calm technology defaults to the minimum necessary notifications and more naturalistic design.
Source images: Xreal; Patrick T. Fallon/AFP/Getty Images
Rounding out the list, this feature article considered a fundamental question in consumer tech: What do users actually want? With smart glasses finally on the verge of mainstream use, contributor Alfred Poor compares two paths forward for the wearable tech. “Should a head-worn display replicate the computer screens that we currently use, or should they work more like a smartwatch, which displays only limited amounts of information at a time?” Two smaller companies, Xreal and Halliday, offer AR glasses that represent the two design concepts, and the tradeoffs between them.
2025-12-27 21:00:01
How fast you can train gigantic new AI models boils down to two words: up and out.
In data-center terms, scaling out means increasing how many AI computers you can link together to tackle a big problem in chunks. Scaling up, on the other hand, means jamming as many GPUs as possible into each of those computers, linking them so that they act like a single gigantic GPU, and allowing them to do bigger pieces of a problem faster.
The two domains rely on two different physical connections. Scaling out mostly relies on photonic chips and optical fiber, which together can sling data hundreds or thousands of meters. Scaling up, which results in networks that are roughly 10 times as dense, is the domain of much simpler and less costly technology—copper cables that often span no more than a meter or two.
But the increasingly high GPU-to-GPU data rates needed to make more powerful computers work are coming up against the physical limits of copper. As the bandwidth demands on copper cables approach the terabit-per-second realm, physics demands that they be made shorter and thicker, says David Kuo, vice president of product marketing and business development at the data-center-interconnect startup Point2 Technology. That’s a big problem, given the congestion inside computer racks today and the fact that Nvidia, the leading AI hardware company, plans an eightfold increase in the maximum number of GPUs per system, from 72 to 576 by 2027.
“We call it the copper cliff,” says Kuo.
The industry is working on ways to unclog data centers by extending copper’s reach and bringing slim, long-reaching optical fiber closer to the GPUs themselves. But Point2 and another startup, AttoTude, advocate for a solution that’s simultaneously in between the two technologies and completely different from them. They claim the tech will deliver the low cost and reliability of copper as well as some of the narrow gauge and distance of optical—a combination that will handily meet the needs of future AI systems.
Their answer? Radio.
Later this year, Point2 will begin manufacturing the chips behind a 1.6-terabit-per-second cable consisting of eight slender polymer waveguides, each capable of carrying 448 gigabits per second using two frequencies, 90 gigahertz and 225 GHz. At each end of the waveguide are plug-in modules that turn electronic bits into modulated radio waves and back again. AttoTude is planning essentially the same thing, but at terahertz frequencies and with a different kind of svelte, flexible cable.
Both companies say their technologies can easily outdo copper in reach—spanning 10 to 20 meters without significant loss, which is certainly long enough to handle Nvidia’s announced scale-up plans. And in Point2’s case, the system consumes one-third of optical’s power, costs one-third as much, and offers as little as one-thousandth the latency.
According to its proponents, radio’s reliability and ease of manufacturing compared with those of optics mean that it might beat photonics in the race to bring low-energy processor-to-processor connections all the way to GPU, eliminating some copper even on the printed circuit board.
So, what’s wrong with copper? Nothing, so long as the data rate isn’t too high and the distance it has to go isn’t too far. At high data rates, though, conductors like copper fall prey to what’s called the skin effect.
A 1.6-terabit-per-second e-Tube cable has half the area of a 32-gauge copper cable and has up to 20 times the reach. Point2 Technology
The skin effect occurs because the signal’s rapidly changing current leads to a changing magnetic field that tries to counter the current. This countering force is concentrated at the middle of the wire, so most of the current is confined to flowing at the wire’s outer edge—the “skin”—which increases resistance. At 60 hertz—the mains frequency in many countries—most of the current is in the outer 8 millimeters of copper. But at 10 GHz, the skin is just 0.65 micrometers deep. So to push high-frequency data through copper, the wire needs to be wider, and you need more power. Both requirements work against packing more and more connections into a smaller space to scale up computing.
To counteract the skin effect and other signal-degrading issues, companies have developed copper cables with specialized electronics at either end. With the most promising, called active electrical cables, or AECs, the terminating chip is called a retimer (pronounced “re-timer”). This IC cleans up the data signal and the clock signal as they arrive from the processor. The circuit then retransmits them down the copper cable’s typically eight pairs of wires, or lanes. (There is a second set for transmitting in the other direction.) At the other end, the chip’s twin takes care of any noise or clock issues that accumulate during the journey and sends the data on to the receiving processor. Thus, at the cost of electronic complexity and power consumption, an AEC can extend the distance that copper can reach.
Don Barnetson, senior vice president and head of product at Credo, which provides network hardware to data centers, says his company has developed an AEC that can deliver 800 Gb/s as far as 7 meters—a distance that’s likely needed as computers hit 500 to 600 GPUs and span multiple racks. The first use of AECs will probably be to link individual GPUs to the network switches that form the scale-out network. This first stage in the scale-out network is important, says Barnetson, because “it’s the only nonredundant hop in the network.” Losing that link, even momentarily, can cause an AI training run to collapse.
But even if retimers manage to push the copper cliff a bit farther into the future, physics will eventually win. Point2 and AttoTude are betting that point is coming soon.
AttoTude grew out of founder and CEO Dave Welch’s deep investigations into photonics. A cofounder of Infinera, an optical telecom–equipment maker purchased by Nokia in 2025, Welch developed photonic systems for decades. He knows the technology’s weaknesses well: It consumes too much power (about 10 percent of a data center’s compute budget, according to Nvidia); it’s extremely sensitive to temperature; getting light into and out of photonics chips requires micrometer-precision manufacturing; and the technology’s lack of long-term reliability is notorious. (There’s even a term for it: “link flap.”)
“Customers love fiber. But what they hate is the photonics,” says Welch. “Electronics have been demonstrated to be inherently more reliable than optics.”
Fresh off Nokia’s US $2.3 billion purchase of Infinera, Welch asked himself some fundamental questions as he contemplated his next startup, beginning with “If I didn’t have to be at [an optical wavelength], where should I be?” The answer was the highest frequency that’s achievable purely with electronics—the terahertz regime, 300 to 3,000 GHz.
“You start with passive copper, and you do everything you can to run in passive copper as long as you can.” —Don Barnetson, Credo
So Welch and his team set about building a system that consists of a digital component to interface with the GPU, a terahertz-frequency generator, and a mixer to encode the data on the terahertz signal. An antenna then funnels the signal into a narrow, flexible waveguide.
As for the waveguide, it’s made of a dielectric at the center, which channels the terahertz signal, surrounded by cladding. One early version was just a narrow, hollow copper tube. Welch says that the second-generation cable—made up of fibers only about 200 µm across— points to a system with losses down to 0.3 decibels per meter—a small fraction of the loss from a typical copper cable carrying 224 Gb/s.
Welch predicts this waveguide will be able to carry data as far as 20 meters. That “happens to be a beautiful distance for scale-up in data centers,” he says.
So far, AttoTude has made the individual components—the digital data chip, the terahertz-signal generator, the circuit that mixes the two—along with a couple generations of waveguides. But the company hasn’t yet integrated them into a single pluggable form. Still, Welch says, the combination delivers enough bandwidth for at least 224 Gb/s transmission, and the startup demonstrated 4-meter transmission at 970 GHz last April at the Optical Fiber Communications Conference, in San Francisco.
Point2 has been aiming to bring radio to the data center longer than AttoTude has. Formed nine years ago by veterans of Marvell, Nvidia, and Samsung, the startup has pulled in $55 million in venture funding, most notably from computer cables and connections maker Molex. The latter’s backing “is critical, because they’re a major part of the cable-and-connector ecosystem,” says Kuo. Molex has already shown that it can make Point2’s cable without modifying its existing manufacturing lines, and now Foxconn Interconnect Technology, which makes cables and connectors, is partnering with the startup. The support could be a big selling point for the hyperscalers who would be Point2’s customers.
Nvidia’s GB200 NVL72 rack-scale computer relies on many copper cables to link its 72 processors together.NVIDIA
Each end of the Point2 cable, called an e-Tube, consists of a single silicon chip that converts the incoming digital data into modulated millimeter-wave frequencies and an antenna that radiates into the waveguide. The waveguide itself is a plastic core with metal cladding, all wrapped in a metal shield. A 1.6-Tb/s cable, called an active radio cable (ARC), is made up of eight e-Tube cores. At 8.1 millimeters across, that cable takes up half the volume of a comparable AEC cable.
One of the benefits of operating at RF frequencies is that the chips that handle them can be made in a standard silicon foundry, says Kuo. A collaboration between engineers at Point2 and the Korea Advanced Institute of Science and Technology, reported this year in the IEEE Journal of Solid-State Circuits, used 28-nanometer CMOS technology, which hasn’t been cutting edge since 2010.
As promising as their tech sounds, Point2 and AttoTude will have to overcome the data-center industry’s long history with copper. “You start with passive copper,” says Credo’s Barnetson. “And you do everything you can to run in passive copper as long as you can.”
The boom in liquid cooling for data-center computing is evidence of that, he says. “The entire reason people have gone to liquid cooling is to keep [scaling up] in passive copper,” Barnetson says. To connect more GPUs in a scale-up network with passive copper, they must be packed in at densities too high for air cooling alone to handle. Getting the same kind of scale-up from a more spread-out set of GPUs connected by millimeter-wave ARCs would ease the need for cooling, suggests Kuo.
Meanwhile, both startups are also chasing a version of the technology that will attach directly to the GPU.
Nvidia and Broadcom recently deployed optical transceivers that live inside the same package as a processor, separating the electronics and optics by micrometers rather than centimeters or meters. Right now, the technology is limited to the network-switch chips that connect to a scale-out network. But big players and startups alike are trying to extend its use all the way to the GPU.
Both Welch and Kuo say their companies’ technologies could have a big advantage over optical tech in such a transceiver-processor package. Nvidia and Broadcom—separately—had to do a mountain of engineering to make their systems possible to manufacture and reliable enough to exist in the same package as a very expensive processor. One of the many challenges is how to attach an optical fiber to a waveguide on a photonic chip with micrometer accuracy. Because of its short wavelength, infrared laser light must be lined up very precisely with the core of an optical fiber, which is only around 10 µm across. By contrast, millimeter-wave and terahertz signals have a much longer wavelength, so you don’t need as much precision to attach the waveguide. In one demo system it was done by hand, says Kuo.
Pluggable connections will be the technology’s first use, but radio transceivers co-packaged with processors are “the real prize,” says Welch.