Users embrace OpenLight's silicon photonics platform

OpenLight, the open silicon photonics platform provider, can point to a successful 2024 signing up new customers. 

In 2023, OpenLight had three customers bringing photonic integrated circuit (PIC) designs to market. OpenLight has since added 14 more.  

OpenLight was formed in 2022 when Juniper Networks carved out its silicon photonics arm. Synopsys acquired a three-quarters stake in OpenLight, while Juniper retained a quarter.

“In the past, the company hadn’t really done any revenue, including when they were in Juniper,” says Adam Carter, OpenLight’s CEO (pictured). “We’ve seen a ten times increase and shown that we can be very profitable.”

The start-up has been creating industry partnerships to better serve its customers' circuit design, chip manufacturing, and packaging needs.

Silicon photonics foundry partner  

Tower Semiconductor was the silicon photonic design team’s chosen foundry long before OpenLight was spun out of Juniper. 

Tower now has three dedicated process design kits (PDKs) that take an OpenLight circuit design and run it through the foundry’s wafer manufacturing process line.  

The PDKs cover a standard silicon photonics process, one tailored for light detection and ranging (Lidar) applications and one offering distributed feedback (DFB) lasers for artificial intelligence (AI) and high-bandwidth data centre PIC applications.  

“You have different specified components in a Lidar process than the data centre one,” says Carter. 

For example, the DFB laser requires a diffraction grating to be built into the silicon. The DFBs are used for optical engines supporting coarse wavelength division multiplexing (CWDM) and will support 200-gigabit optical lanes. 

OpenLight, working with Riga Technical University and Keysight Technologies, published a post-deadline paper at OFC earlier this year, showing a DFB laser design path for 400-gigabit optical lanes. Future 3.2-terabit transceiver optical engines will need such DFBs.  

More partnerships

OpenLight also works using several electronic design automation (EDA) tool environments. 

Unsurprisingly, OpenLight works closely with photonic EDA tool specialist Synopsys. "We help them with some of their optical simulation models, and they use us for anything new they're rolling out," says Carter. 

However, OpenLight also works with other tool vendors to support its customers' needs and has a partnership with Luceda Photonics, a provider of layout tools.

The start-up has also signed deals with PIC specialists VLC Photonics and Spark Photonics. Since OpenLight has only so many design engineers, it has partnered with the two firms to provide additional design support.  

"We have a chip design that we give them, and we ensure their work follows the design rules and guidelines," says Carter. "Once the design looks good, we sign it off."  The two photonic design firms also develop photonic components for OpenLight to grow its PDK library offerings.

OpenLight has a partnership with manufacturing firm Jabil to provides its customers with services such as assembly, packaging, burn-in, and testing. "As a customer, you take a wafer from Tower, give it to Jabil, and what comes out is a packaged product," says Carter.  

Jabil bought Intel's optical module unit last year, and Carter says there is an opportunity to supply PICs to that unit, too. 

The start-up is also exploring other packaging partners based in Asia to support its customers there.

Lidar opportunities 

Two styles of Lidar systems are used for such applications as automotive, autonomous vehicles, and machine vision systems. 

One approach, known as time-of-flight, uses VCSELs as the light source. Such systems have limited reach, and the weather can curtail their performance. The second approach is frequency-modulated continuous wave (FMCW) Lidar, which achieves superior range and resolution performance. 

But FWCM requires signal amplification, says Carter, something OpenLight can offers with its monolithic process technology that can integrate semiconductor optical amplifiers.

"Much of the work we're doing with potential Lidar customers is around the fact that we can amplify the signal," he says. 

Carter says time-of-flight systems are the dominant approach for automotive applications in China, but players there are considering alternative architectures. "We are working with Chinese customers on this type of application," says Carter.

800-gigabit reference designs

OpenLight also offers two 800-gigabit PIC reference designs: an 8x100-gigabit (800G-DR8) design and an 800-gigabit 2xFR4 CWDM one. 

The reference designs help OpenLight's work with sub-assembly companies with their fibre attach units. OpenLight is also using them with its work with electronics suppliers providing PAM-4 (4-level pulse amplitude modulation) digital signal processing (DSP) chips.

"And we are also expanding to an 8x200-gigabit part - a 1.6-terabit DR8, and we're also doing a [1.6-terabit] CWDM variant," says Carter. "These will be the first parts to employ the DFB as the laser source."

At 200 gigabit, the waveguide optical losses are higher. "To meet the specifications, we can add amplification with a semiconductor optical amplifier to boost the output power, compensating for the losses," he says.  

Carter became OpenLight's CEO at the start of 2023 and is pleased with what the start-up has achieved.

"The team is seeing that what they've been working on for several years is becoming a business that can stand on its own," says Carter.