Ayar Labs Inc., a startup developing a new way of linking together chips in data centers, today announced that it has raised $25 million from investors.

The funding was provided as an extension to a $130 million Series C round the startup closed last year. Capital TEN led the new investment, which is described as a Series C1 raise. Nvidia Corp. participated as well along with a number of other backers.

“This C1 adds sophisticated investor partners that will allow us to accelerate our strategic roadmap, and is further validation of our technology and plan to bring silicon photonics-based interconnect solutions to market at scale,” said Ayar Labs Chief Executive Officer Charles Wuischpard.

A server’s processor, memory chips and other components are linked together via copper wires that allow them to exchange data with one another. Data travels over the wires in the form of electric signals. Ayar Labs has developed an interconnect module, TeraPHY, that transmits information between a server’s components in the form of light rather than electricity.

The startup says its technology is considerably faster than traditional copper-based alternatives. According to Ayar, its TeraPHY modules provide 1,000 times higher bandwidth density using less power. The result is that each module can transfer up to 25.6 terabits of data per second between a server’s chips.

The speed of traditional copper-based interconnects is limited by their susceptibility to errors. When data is sent over a copper link at rates above 50 gigabits per second, a technology called forward error correction must be used to ensure the information will arrive at its destination. According to Ayar, the technology increases latency, which in turn slows performance.

The more data is sent over a copper link at once, the greater the likelihood of errors. As a result, it’s becoming increasingly difficult to increase the speed of traditional copper-based interconnects. Ayar Labs claims its optical TeraPHY module avoids that limitation.

TeraPHY is implemented as a chiplet, a module that can be integrated into the design of server processors. Each chiplet includes millions of transistors made using a 45-nanometer process. Additionally, there are hundreds of onboard optical devices responsible for managing the light that TeraPHY uses to transmit data.

TeraPHY doesn’t generate the light itself, but rather relies on an external device called SuperNova to do so. Ayar says the latter device can support bandwidth of more than 8 terabits per second. Moreover, the fact that SuperNova is a standalone module rather than part of TeraPHY means it can be replaced in the event of a malfunction.

The technology not only speeds up data transfer between chips but also provides other benefits. The company claims TeraPHY uses 10 times less power than copper-based alternatives. Moreover, it’s capable of transmitting data between systems located more than 1.2 miles apart.

Ayar envisions chipmakers integrating TeraPHY modules into central processing units, graphics cards and other products to increase performance. In the longer term, the startup believes its technology could facilitate new server designs.

Chips such as graphics cards store the data they process in onboard memory circuits. According to Ayar, TeraPHY could make it possible to split off a chip’s onboard memory circuits into a separate module. The startup believes such an approach could speed up workloads such as artificial intelligence models.

Currently, breaking up processors into multiple devices is impractical because it would increase the distance that data has to travel between the different parts of a server. The increased travel time, in turn, would slow processing. Ayar says its TeraPHY interconnect’s high speed addresses that limitation.

The company will use the proceeds from its latest $25 million raise to support chip development and commercialization efforts. As part of the effort, Ayar plans to expand its chip portfolio with new products.

Photo: Ayar Labs