# How Silicon Photonics Is Breaking Data Center Bottlenecks

An episode of [The Hardware Podcast with Fexingo: Chips, Devices, and Electronics Engineering Conversations](https://invisiblenetwork.ai/podcast/1896799982), 29 May 2026, 9:41.

Audio: https://audio.fexingo.com/business/the-hardware-podcast/episode-0019.mp3

Lucas and Luna explore the emerging field of silicon photonics, which uses light instead of electricity to move data inside data centers. They explain why electrical interconnects are hitting a wall as chip speeds increase, and how companies like Intel and Ayar Labs are developing optical transceivers that can transfer data at terabit speeds while using less power. The episode walks through the physics of why copper wires struggle at high frequencies, how silicon manufacturing makes photonics economically viable, and when we might see these chips in production. A concrete look at a technology that could reshape cloud computing infrastructure. #SiliconPhotonics #DataCenters #Intel #AyarLabs #OpticalInterconnects #TerabitDataTransfer #CopperWires #CloudComputing #Photonics #Semiconductors #LaserTransceivers #ChipDesign #Technology #HardwarePodcast #FexingoBusiness #BusinessPodcast #ElectronicsEngineering #DataCenterInfrastructure Keep every episode free: buymeacoffee.com/fexingo

## Transcript

Lucas: There's a quiet crisis inside every major data center, and it has nothing to do with cooling or energy prices. It's the physical limits of copper wires.
Luna: Copper wires? We're talking about the cables inside servers, right?
Lucas: Right. As processors get faster, the interconnects between them — the wires carrying data from one chip to another — can't keep up. At high enough speeds, electrical signals degrade, they generate heat, and they consume more power than the compute itself.
Luna: So we're hitting a bandwidth wall inside the box.
Lucas: Exactly. And that's where silicon photonics enters the picture. Instead of electrons moving through copper, we use photons — light — travelling through tiny silicon waveguides. Light doesn't generate heat the same way, it doesn't degrade over distance the same way, and it can carry far more data per second.
Luna: I've heard about photonics for long-haul telecom — fibre optic cables under the ocean. But inside a data center, that's a different scale entirely.
Lucas: Totally different. Long-haul uses expensive discrete components: lasers, modulators, detectors, all assembled by hand. Silicon photonics tries to build those same functions on a standard CMOS chip — the same process used to make your laptop's CPU. That's the breakthrough.
Luna: So you can manufacture them at scale, in existing fabs, without exotic materials.
Lucas: That's the promise. Intel has been working on this for over a decade. They announced a fully integrated silicon photonics transceiver a few years ago, capable of 800 gigabits per second per fibre. And they're now shipping products to cloud providers. But they're not alone.
Luna: Who else is in the race?
Lucas: Ayar Labs is a notable startup — spun out of MIT, backed by NVIDIA and GlobalFoundries. They focus on optical I/O chiplets that sit right next to the processor, replacing the electrical SerDes interface. Their current generation does four tera-bits per second — that's four trillion bits per second — per chiplet.
Luna: That number is hard to wrap your head around. Four terabits per second. For context, a typical home internet connection is maybe one gigabit.
Lucas: Four thousand times faster. And the power savings are equally dramatic. Electrical interconnects at those speeds can consume tens of picojoules per bit. Silicon photonics gets down to under one picojoule per bit. In a hyperscale data center with hundreds of thousands of links, that difference translates to megawatts of saved power.
Luna: So it's not just about speed — it's about energy efficiency. Which ties directly to operational costs and sustainability goals.
Lucas: Precisely. And the timing matters because of a trend called compute disaggregation. Instead of packing everything into one giant server, data centers are moving to pools of CPUs, GPUs, memory, and storage that are connected by high-speed networks. Those networks are the bottleneck.
Luna: If you have a pool of GPUs on one rack and a pool of memory on another, you need a way to move data between them without latency or bandwidth constraints.
Lucas: Right. And copper gets you maybe a few metres before the signal degrades. Optical can go hundreds of metres with no loss. That changes the architecture entirely. You can build much larger, more flexible compute clusters.
Luna: What about the laser itself? I've read that integrating a laser onto a silicon chip is one of the hardest parts.
Lucas: It is. Silicon is an indirect bandgap material — it's terrible at emitting light. So most silicon photonics chips use a separate laser source, either bonded onto the chip or coupled externally. Intel uses a hybrid approach where they bond indium phosphide laser dies onto the silicon photonics chip. Ayar Labs keeps the laser external and couples it via fibre.
Luna: So there's no pure monolithic solution yet — you still need iii v materials for the light source.
Lucas: Correct. That's one of the remaining engineering challenges. Another is packaging: aligning fibres to a chip with sub-micron precision is hard to do at volume. But the industry is making progress. There are now automated alignment tools that can do it.
Luna: And all this is happening because the electrical alternative is hitting a wall. What's the specific limit with copper?
Lucas: At frequencies above roughly 50 gigahertz, the skin effect and dielectric losses cause signal attenuation that grows exponentially with frequency. You can equalise it, but that consumes power and adds complexity. The industry consensus is that electrical I/O will max out around 200 to 300 gigabits per second per lane in the next few years. Optical can already do 400 gigabit per lane and scale beyond.
Luna: So it's not theoretical — the limits are known and approaching fast.
Lucas: Right. And this is why the biggest cloud providers — Amazon, Google, Microsoft — are all investing heavily in silicon photonics. They're not waiting for the wall to hit; they're preparing to leap over it.
Luna: Before we go deeper, I want to take a quick step back. You know, this kind of deep-dive into the tech behind data centers is exactly why this show exists — because understanding these shifts matters. And if you find these conversations valuable, there's a simple way to support the show and keep it ad-free.
Lucas: Yeah, we get asked about this sometimes. If you want to chip in, you can visit buy me a coffee dot com slash fexingo. Totally optional, but it helps us keep doing episodes like this without sponsors or ads.
Luna: And we really appreciate it. Okay, back to photonics — Lucas, you mentioned Intel and Ayar Labs. What about the timeline for broader adoption?
Lucas: We're already past the early adopter phase. Intel has been shipping its 100-gigabit silicon photonics transceivers since 2016, and its 400-gigabit products are in production now. Ayar Labs expects to have its optical I/O chiplets in volume production by 2027. The bigger shift will come when the technology moves from interconnects inside the data center to interconnects inside the server itself — chip to chip, even on the same package.
Luna: On-package optics — that's the holy grail, right? Replacing the electrical traces on a circuit board with optical waveguides.
Lucas: Exactly. Several research groups have demonstrated polymer waveguides embedded in printed circuit boards. But the real prize is co-packaged optics, where the optical transceiver is integrated into the same package as the switch or processor chip. That eliminates the electrical link between the chip and the front-panel connector, which is a major source of power loss and signal degradation today.
Luna: Is there a standard for that? Or is everyone doing their own thing?
Lucas: There are consortiums working on it — the Co-Packaged Optics Collaboration, for example, which includes Cisco, IBM, Intel, and others. But it's still fragmented. The industry is sorting out form factors, connector standards, and testing methodologies. It'll take a few more years to settle.
Luna: What about cost? Photonics has traditionally been expensive compared to copper.
Lucas: Historically yes, but the cost gap is closing. Silicon photonics benefits from the same economies of scale as CMOS manufacturing. Once you're making millions of units in a 300 millimeter fab, the marginal cost per chip drops dramatically. Analysts at LightCounting project that silicon photonics transceivers will reach cost parity with copper-based active optical cables by 2028 or 2029.
Luna: So within three years, it's not just better performance — it's also cheaper.
Lucas: That's when adoption really accelerates. Because data centers don't just want speed; they need to hit total cost of ownership targets. If photonics saves power, reduces cooling load, and costs the same or less, the decision makes itself.
Luna: Are there any downsides or risks? I imagine reliability is a concern with lasers.
Lucas: Reliability is a real issue. Lasers degrade over time, especially at high temperatures. Silicon photonics transceivers need to operate reliably for years in data center environments. Manufacturers have to qualify their devices for thousands of hours of operation at elevated temperatures. But the industry has made huge strides — Intel's transceivers have a mean time between failures measured in millions of hours.
Luna: So it's proven at scale, at least for certain use cases.
Lucas: Yes. And the next frontier is not just data centers — it's high-performance computing, autonomous vehicles, and even eventually consumer devices. If you can bring optical interconnects to the motherboard of a laptop, you could radically change form factors and power budgets.
Luna: That's a long way off, but the trajectory is clear.
Lucas: Absolutely. For now, the action is in the cloud. And it's quietly reshaping the economics of computing.

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