Silicon photonics is resurfacing after more than 10 years within the shadows, driven by demands to go larger quantities of data faster, using extremely low power and with reduced heat.
Until recently, most of the eye in photonics centered on moving data between servers and storage. Presently there is growing interest at the PCB level and in heterogeneous multi-chip packages. Government, academic and and commercial investments in this technology are all from the rise, and there clearly was a renewed feeling of optimism that this technology will become useful across more markets and applications.
“In the early 2000s there was clearly lots of energy being put in photonics,” said Gnyaneshwar Ramakrishna, chairman regarding the photonics technical committee for IEEE’s Components, Packaging and Manufacturing Technology Society. “That died down for a while. The good news is that we’re able to show speeds of 25 Gbps to 100 Gbps, photonics is originating back in a way that is big. It’s getting used for short reach and long reach in data centers, and we’re seeing a necessity for photonics during the modular level. Our company is taking care of how to carry it onto a board. There is certainly, finally, so to speak, a light in the final end of the tunnel.”
No one knows how far this technology will go, or the timing of when it will begin to show up in packages or on chips at this point. “Bringing it in to the chip is everybody’s dream,” said Ramakrishna. “To make that happen, architectural solutions and technologies need to come right into place. Right now, those building blocks have been in progress. The ecosystem, and it also does take time. to grow it to scale requires the supply chain”
The ecosystem seems to be firmly up to speed, though. “Silicon photonics will likely be a $33 billion to $35 billion industry,” said Sanjay Jha, CEO of GlobalFoundries, during a speech that is recent. “There is supposed to be a dramatic increase. It will be properly used for all the data in cars and connectivity between racks of servers. You will see a distribution that is seamless of within the data center.”
Funding is increasing, as well. In 2014, the U.S. government developed the Integrated Photonics Manufacturing Institute, spearheaded by the U.S. Department of Defense, with more than $200 million in available funds. To date, three states have jumped in along with their own funding—New York, California and Massachusetts, and there’s support that is growing private industry. The funding that is current in accordance with industry insiders, happens to be as much as just over $600 million.
The purpose of a few of these efforts is to eke efficiencies and economies of scale out of silicon photonics, since the semiconductor industry did with digital logic and memory Moore’s that is using Law a guide. Silicon photonics can be regarded as a way of moving more data more proficiently, and much more securely, nevertheless the price needs to drop significantly for this to reach a wider audience.
For processors to work with photonics, optical signals have to be changed into signals that are electrical. Scientific studies are underway to process and store optical signals, sidestepping that entire conversion process, but most experts believe it is years before a solution is ready, and even then it is questionable whether or not it is supposed to be cost-effective.
At this stage, the three leaders in this field are Cisco, Intel and IBM. For the three, only Cisco is shipping the technology in quantity in a number of devices.
To essentially hit the mainstream, price-sensitive chip market, two key problems need to be solved. First, there has to be a better way to install a laser, that is the source of light for photonics, to a silicon platform.
“One challenge is that lasers built today are using III-V materials, which are inherently not compatible with CMOS,” said Kaushik Patel, director of engineering for silicon photonics development at Cisco. “There is work underway with quantum dots to cultivate a laser, but right now lasers are discrete parts.”
The challenge that is second with how exactly to extend the life of the lasers. “Today’s lasers have limited life,” said Patel. Outside of this silicon.“So we want a way to efficiently couple photons, and we need an efficient way to couple them”