Part 2: Start-up funding
Scintil Photonics is betting that to keep scaling AI compute systems, integrated laser arrays will be needed alongside AI accelerator chips.
Scintil Photonics, a spin-off from French research lab CEA-Leti, has developed a heterogeneous integration photonics platform that combines indium phosphide lasers with silicon photonics.
The Grenoble-based start-up’s focus is to deliver light sources to feed co-packaged optics (CPO) in data centres. But its ambitions go beyond that.
“I’m convinced that we have absolutely the best heterogeneous integration technology platform in the world,” says Matt Crowley, who joined Scintil as CEO a year ago. “It was developed for a long time, it’s very difficult for others to replicate, it’s been scaled at [foundry] Tower Semiconductor, so it’s proven its manufacturability.”
Scintil’s task is to replace the piece-part manufacturing of numerous discrete optical components with a monolithically integrated design. “At Scintil, we want to take that to the next level by taking silicon photonics and bringing III-V and other more exotic materials into that integration flow,” he says.
Crowley’s background is in MEMS and semiconductors. He founded Vesper Technologies, a company specialising in MEMS microphones and accelerometers, which Qualcomm later acquired. Previously, he helped scale the start-up Sand 9, which was acquired by Analog Devices. That experience—turning custom wafer processes into high-volume production—is Scintil’s next challenge. “At my last company, we scaled to 60 million units with design wins at Samsung and Amazon,” says Crowley.
For most deep-tech start-ups, particularly wafer-based ones, transitioning from a few hundred prototypes to a manufacturing process that can produce millions of units is challenging.
“You have to convince customers you’ll be a reliable supplier, even assuming your specifications are better,” he says.
Structure and scale
Scintil recently raised €50 million in its Series B funding round. The backers include Yotta Capital Partners and NGP Capital, with participation from Nvidia and earlier investors.
“It was great to get that validation,” says Crowley. “Now we have to figure out how to ramp the product to production.” The funding will help the company expand its 50-staff and sites globally.
The company’s headquarters and core engineering are in Grenoble, France, complemented by designers in Toronto and the UK. A California office is planned as a customer-support lab, while Crowley is based in Boston.
“The primary location will be Grenoble, where engineering and operations sit,” says Crowley. California will likely be the second-largest office, where Scintil will work with customers to get systems up and running.
First bet
When Crowley joined Scintil a year ago, the start-up had two product directions. One was a generic photonic integrated circuit (PIC) platform, and the other was the external light source. The first significant decision he took was to focus solely on laser sources, where the company has seen strong customer interest. Crowley refers to this as being ‘laser-focussed on lasers”.
“In my experience, one of a start-up’s greatest advantages is focus,” he says. “A small group with high talent and great teamwork can out-execute larger groups.”
The goal is to develop Scintil’s LEAF Light product, a dense wavelength division multiplexing (DWDM) external laser source designed for next-generation co-packaged optics.
Accordingly, Scintil’s goal is to launch the light-source product, focussing the start-up on that. “To prove our platform and to prove the value of our IP, we have to launch a single product,” says Crowley.
Here, what is required are laser designs with high power, high reliability, and low cost and size. “There are two specs that are really important: wall-plug efficiency, but even more critically, channel spacing and consistency of manufacturing,” says Crowley.
Scintil believes that traditional distributed feedback (DFB) laser manufacturing won’t scale to the tens of millions of dense WDM array chips that will be needed starting in 2028.
Leaf light: precision and power
Scintil’s external light source is a monolithically integrated array of indium phosphide distributed-feedback (DFB) lasers, in configurations of 8 or 16 wavelengths, on a silicon photonics chip.
Each light source chip also features integrated waveguides and on-chip multiplexers, which combine the wavelengths of multiple lasers onto a single fibre. The design also integrates photodetectors and thermal-tuning elements to stabilise wavelength drift. “We take detectors, waveguides, all from the silicon-photonics toolkit at Tower Semiconductor, and put them on one chip with our DFB array,” says Crowley.
Scintil can support the CW-WDM multi-source agreement frequency grid where customers require it. “We are looking at what the customer wants,” says Yannick Paillard, Scintil’s chief commercial officer. “If they want the CW-WDM frequency grid, we can deliver that.”
Scintil can deliver 8-wavelength implementations at 200GHz spacings or 16-wavelength implementations at 100GHz spacings. And the company’s product will support more than one fibre output—eight wavelengths times eight fibres, for example.
“Because Scintil uses advanced semiconductor lithography, our lasers have better than ±10GHz precision,” Crowley says. “Competition struggles to get better than ±50GHz. That’s architecturally important because if your channels are too close, they start to interfere with each other downstream.”
Power output and efficiency are also on the roadmap. “We’ve achieved up to 20 milliwatts per carrier,” he says. “Market demand for higher power is increasing as customers want to split signals and generate more carriers.”
As for energy efficiency, Scintil cites Nvidia’s published results. “They’ve shown that the dense WDM co-packaged optics approach can get to sub-4 picojoules per bit today, with a path below one picojoule per bit,” says Crowley. “At that point, optics become more power-efficient than copper.”
Framed against copper, the objective is to achieve power per bit comparable to, and ultimately better than, copper at relevant distances.
Manufacturing partnerships
Production leverages Tower Semiconductor’s PH18 silicon-photonics platform, with Scintil performing post-processing to form the indium-phosphide lasers.
“Tower manufactures the silicon-photonics wafer,” Crowley explains. “Then it goes to Scintil, where we have a wafer probe station with a custom probe head and optical measurement capability that we developed. We can do optical measurement of every die on a wafer.” The goal is to transfer that flow to high-volume assembly partners, or OSATs, as volumes increase.
“We’ll take our custom probe head and install it at an OSAT,” he says. “That’s how we scale. I can collect statistical data, feed it back to the foundry and design teams, and get into a continuous-improvement cycle.”
This known-good-die approach also offers flexibility. “Large customers may want to do their own assembly or co-package with other chips,” Crowley adds. “We’re open to selling them known-good dies or full modules.”
Scintil has already given companies samples of its product. The expectation is that it will make several thousand chips in 2026.
Speaking about the challenge of a start-up getting into the biggest accounts, Crowley says it is key to make life as easy as possible for partners.
“Do as much work for them as you can — build the full module, qualify it, give them the reliability data, the audit reports. That’s how you get designed in,” says Crowley.
Reliability
Coming from the MEMS world, Crowley brings a distinct perspective on reliability targets. “My last company had a failure rate of 0.2 parts per million,” he recalls. “In this industry, when someone says 0.7 per cent failure rate, there’s incredible room for improvement.”
He calls reliability “the hidden spec” in photonics. “We treat it as another design parameter,” he says. “If a metal trace is too thin or a layer isn’t laminating correctly, we expect designers and process engineers to fix it. Once wafer-level technology is working, you get a virtuous cycle: costs go down, performance and reliability go up.”
Scintil’s push to industrialise heterogeneous integration is one of many elements that will determine how the optics industry keeps pace with AI’s compute appetite.
Click here for Part 1: Start-up funding