OpenLight’s integrated-laser silicon photonics platform

OpenLight is coming to market with an open silicon photonics platform that includes integrated lasers and gain blocks.

Juniper has a long relationship with Synopsys, using its electronic-photonic design automation (EPDA) tools.

So when Juniper said it was spinning out its silicon photonics group, Synopsys was keen to partner.

The result is OpenLight, of which Synopsys has a 75 per cent stake costing $67.5 million.

Thomas Mader, OpenLight’s chief operating officer and formerly head of Juniper’s silicon photonics unit, says OpenLight is the first company to offer an open platform that includes monolithically integrated lasers, optical amplifiers and modulators. 

Juniper Networks and Synopsys

Juniper gained its silicon photonics technology in 2016 when it acquired Aurrion for $165 million.

Aurrion was a fabless silicon photonics start-up from the University of California, Santa Barbara, with a heterogeneous integration silicon photonics process that includes III-V materials, enabling integrated lasers as part of a photonic circuit. 

OpenLight is now making this technology available through its partnership with the foundry Tower Semiconductor.   

Juniper’s interests are mainly datacom and telecom, but it recognises the emerging opportunities for silicon photonics such as Lidar, optical computing, high-performance computing and optical interconnect. 

“With this kind of technology, you want to drive volumes,” says Mader.

Juniper saw spinning out the unit and opening up access to the technology as the best way to drive volumes and reduce costs. The arrangement also benefits Juniper’s own technology needs. 

Synopsys, meanwhile, believes it is the right time to back the OpenLight venture. 

“We think it [the open platform] is a great opportunity for growth for Synopsys’s EPDA tools,” says John Koeter, senior vice president of marketing and strategy, solutions group at Synopsys. 

OpenLight will give Synopsys insight into how the market is evolving and benefit the company’s tools and, eventually, its IP.

Business model

OpenLight is licensing its process design kit (PDK), the files that model Tower’s fabrication process. A company can enter into an agreement with Tower, access the PDK and design its silicon photonics device. 

“What we are offering through Tower, and what we spent significant effort developing and showing Tower how to do, is monolithically integrating lasers and optical gain,” says Mader. “Tower is the first time we’re on a volume eight-inch [wafer] process.” 

Juniper entered into a partnership with Tower Semiconductor in 2019.  

“We are doing the first MPW [multi-project wafer] this summer with Tower on this process,” says Mader. 

OpenLight is also providing designs it has developed and validated for several customers. “But we are not selling PICs [photonic integrated circuits]; that is not part of our plan,” says Mader.

OpenLight intends to partner with other foundries to make more widely available integrated-laser designs.

For now, though, OpenLight is focussed on ratifying its roadmap for the next two years. 

“We’re going to be busy building out the component library for Tower to keep customers interested because better components make better circuits,” says Daniel Sparacin, vice president of business development and strategy at OpenLight.

OpenLight offers a 100-gigabit modulator and is working on its next-generation 200-gigabit modulator.  

“We’re mostly O-band right now, and we have C-band coming up in the roadmap very shortly,” says Sparacin.

Applications

OpenLight has 400 and 800-gigabit optical designs for the data centre to help customers bring to market their PIC developments. 

The company is also seeing interest from Lidar customers, particularly those pursuing coherent-based designs. 

“The main reason is the integrated laser,” says Mader. “Otherwise, with standard silicon photonics, you have to attach a laser separately, which doesn’t scale well to multiple channels.” That’s because attaching multiple lasers impacts yield.

Lidar also benefits from on-chip optical amplification. “When you have a complex chip, you have a lot of losses,” says Mader.

OpenLight is working with firms pursuing optical computing for machine learning which promises greater power efficiency. “There are several of them coming to us because we can put hundreds or thousands of indium phosphide elements monolithically on a chip,” says Mader. 

OpenLight says it has no position regarding co-packaged optics and whether a design uses an external light source or integrated lasers.

It believes co-packaged optics designs will eventually use integrated light sources, but its technology supports both and can even be used to make external light sources. 

Overall, OpenLight says it is working with dozens of companies.   

Design tools and integration

Synopsys has been an early mover with its integrated optical design automation tools. The tools include:

Working closely with OpenLight will benefit Synopsys’s tool environment, says Koeter. Synopsys is adding functionalities and design capabilities to its tools to support the integration of lasers. OpenLight is also providing Synopsys feedback on what will improve the experience of using its design platform.

Synopsys is one of three electronic design automation (EDA) tool companies. However, design tools for photonics are a more recent development.

“EDA quite a while ago is where photonic design is now going,” says Mader. 

Integration is the underlying trend driving optics.

“We see the scaling already with 400- and 800-gigabit for datacom and some of the other applications; you see the shift to silicon photonics,” says Mader. “The higher the complexity, the more you see it shifting this way because there’s a cost advantage with the integrated laser and optical gain.” 

Photonics may not come close to chip designs with billions of transistors. Still, photonic designs that go beyond four-channel design to ones with 32 or 64 channels or optical computing with hundreds or thousands of components are emerging. 

“So you see a scaling even though it’s decades behind the electronics field,” says Mader. 

With monolithically integrated lasers, yields remain high, whereas scaling a design with discrete components results in unacceptable yields. 

“And so we will be able to go where you can’t go otherwise,” says Mader. “It’s not billions, but even dozens [of components] at this point is revolutionary.”