From spin-out to scale-up: OpenLight’s $34M funding

Part 1: Start-up funding

OpenLight Photonics, a Santa Barbara-based start-up specialising in silicon photonics, has raised $34 million in an oversubscribed Series A funding round.

The start-up will use the funding to expand production and its photonic integrated circuit (PIC) design staff.

“We’re starting to get customers taking in production mask sets, so it’s about scaling operations and how we handle production,” says OpenLight CEO, Adam Carter (pictured). The start-up needs more PIC designers to work with customers.

Technology

OpenLight’s technology originated at Aurrion, a fabless silicon photonics start-up from the University of California, Santa Barbara. 

Aurrion’s heterogeneous integration silicon photonics technology supports III-V materials, enabling components such as lasers, modulators, and optical amplification to be part of a photonic integrated circuit (PIC). Intel has its own heterogeneous integration silicon photonics process, which it has used to make millions of pluggable optical transceivers. OpenLight is offering the technology to customers effectively as a photonic ASIC design house. 

Juniper Networks bought Aurrion in 2016 and, in 2022, spun out the unit that became OpenLight. Electronic design tool specialist Synopsys joined Juniper in backing the venture. Synopsys announced it was acquiring simulation company Ansys, a $35 billion deal it completed in July. Given that Synopsys would be focused on integrating Ansys, it suggested to OpenLight in January that they should part ways.

Funding

“We were only looking for $25 million to start with, and we finished at $34 million,” says Carter. Capricorn Investment Group was a late entrant and wanted to co-lead the funding round. Given initial commitments from other funders, Mayfield and Xora Innovation, set specific ownership percentages, it required an increase to accommodate Capricorn.

Xora’s first contact with OpenLight was after it approached the start-up’s stand at the OFC 2025 event held in March.

Juniper—now under HPE—is also an investor. The company played a key role in helping OpenLight while it sought funding. “Juniper could see that we were very close to an intercept point regarding our business model and our customers, so that's why Juniper invested,” says Carter.

HPE continually looks at technologies it will require; silicon photonics with heterogeneous integration is one such technology, says Carter. However, HPE has no deal with OpenLight at this time.

Design roadmap

OpenLight is developing a 1.6-terabit PIC, now at an advanced prototype (beta) stage. The design uses eight channels for a 1.6T-DR8 OSFP pluggable design, implemented using four lasers and eight modulators, each operating at 200 gigabit-per-second (Gbps).

Carter says the first wafers will come from foundry Tower Semiconductor around October. This will be OpenLight’s largest production run — 100 wafers in four batches of 25. Some ten customers will evaluate the PICs, potentially leading to qualification.

A coarse wavelength division multiplexing (CWDM) 1.6-terabit design will follow in 2026. The CWDM uses 4 wavelengths, each at 200Gbps, on a fibre, with two such paths used for the 1.6T OSFP-XD 2xFR4 optical module.

The company is also pushing to develop 400Gbps channels, increasing the frequency response and improving the extinction ratio through process changes.

“We've got a whole series of experiments coming out over the next few months,“ says Carter. The frequency response of the indium phosphide modulator has already been improved by 10 gigahertz (GHz) to 90-95GHz. The process changes will be adopted for some alpha sample wafers in production that may enable modulation at 400Gbps, hence a 3.2-terabit PIC design.

“If we can show some good 3.2-terabit eyes, just as a demo, it shows that there's a technology route to get there whenever 3.2-terabit modules are needed,” he says.

Source: OpenLight 

Customer growth

OpenLight’s customers have grown from three in 2023 to 17 last year to 20 actively designing. “We are growing the pipeline,” says Carter.

Early adopters were start-ups, but now larger firms are engaging Openlight. “Investors noted start-ups take more risk, but now bigger companies are coming in to drive volume,” says Carter.

Optical interconnect will drive initial volumes, but automotive and industrial sensing will follow. “The mix will change, but for the next couple of years, the revenues will be from optical interconnect,” says Carter.

Co-packaged optics is another interconnect opportunity. Here, OpenLight’s integrated laser technology would not be needed, given the co-packaged optics designs favour external laser sources. Instead, the company can offer integrated indium phosphide modulator banks or modulator banks with semiconductor optical amplifiers (SOAs), their compact size—“microns, not millimetres”—aiding packaging.

In addition to the foundry Tower Semiconductor for its wafers, OpenLight partners with Jabil, Sanmina, and TFC for the packaging and does its testing via ISC, an ASE subsidiary.

“They know test and certain customers with ISC, and ASE could do a complete turnkey solution,” says Carter. “But our priority is to get the test area set up to deal with the production; we’ve not had 100 wafers in a year being delivered for test.”

Silicon photonics

Carter, who was at Cisco when it acquired Lightwire in 2012, says silicon photonics' potential to shrink optical designs was already recognised then. Since then, a lot of progress has been made, but now the focus is on building the supporting ecosystem. This includes a choice of foundries offering optical process design kits (PDKs) and outsourced assembly and test houses (OSATs) that can handle volumes.

Until now, silicon photonics has been all passive circuits. Now OpenLight, working with Tower and its PDK, is offering customers the ability to design and make heterogeneous integrated silicon photonics circuits. “Every customer gets the same PDK,” says Carter.

And it need not just be indium phosphide. The idea is to expand the PDK to support modulation materials such as polymer and thin-film lithium niobate. “If it is a better material, we’ll integrate it,” he says.

Having secured the funding, Carter is clear about the company’s priority: “It’s all about execution now.”