Inventor, Professor & Business Leader – UCSB’s Daniel Blumenthal is Solving Complex Problems in Optical Comms
By Rebecca B. Andersen
Hi! I'm Daniel Blumenthal, a Professor of Electrical and Computer Engineering specializing in optical communications and photonic integration at the University of California – Santa Barbara
, Fellow of the National Academy of Inventors (NAI
), The Optical Society (OSA
) and of the IEEE
Today’s high-speed optical communications technologies work to accelerate the way we work, live and play by connecting people and computers around the world over high speed communication pipes. My lab develops new hardware and communications technologies to solve complex communications, transmission, switching and signal processing problems out of reach with today’s technologies. The primary undertaking of our research is to develop new functions integrated on small chips called photonic circuits, and use these circuits to build networks in ways that save energy and increase the scale of connectivity and bandwidth of data centers and the Internet. We are, in theory, greening future networks while allowing them to scale to accommodate future applications and the systems that rely on those networks. We’ve highlighted five key research-related insights from this captivating AMA!
asks — Hi, Prof. Blumenthal. Thank you for doing this AMA. I've read about Moore's Law (an observation that the density of transistors on a chip and thus the computing power) doubles every two years), and was wondering if data transfer has any such equivalent?
— We see data transfer at many levels, there is on chip, between chips, board to board, intra rack, short haul, medium and long haul. These distances and their bandwidth requirement play a key role in your question. What we are seeing it that once we get off the chip, the ability to use optics to transmit data at a certain bit rate over a certain distance can exceed Moore's law. But people solve that problem by parallelizing heavily, so electronics keeps keeping up. We dont have the equivalent today for Moore's law in photonics, just curves that show fiber transmission bandwidth exceeds Moore's law. As photonic chips become denser with more components, we will probably start to get a handle on a Moore type law for photonics. But I imagine this will take 10-20 years.
— Welcome, Where and/or what are the bottlenecks in existing communication hardware?
— Today it is in the chip level I/O. A lot of information can be processed on an electronic chip; state of the art today is 12.5Tbs on a single layer 2 routing chip used in data center top of the rack switches. These chips have 40 inputs and outputs running at 100Gpbs, 200Gbps and soon 400Gbps per port, which is amazing! But the problem now is interfacing all those ports to optics. The board level routing, and density of optical hardware, and all the communications including clock and data recovery, it just keeps adding up and at these capacities is starting to become and engineering and systems build out issue. So today, I think that is one of the key bottlenecks people are looking into at the systems level.
— What are the best future applications of your work?
— That is a big one. We have a huge amount of bandwidth we can cover from the UV, visible to near IR and far IR. So a list of applications could include communications, spectroscopy, atomic clocks, position and navigation, biological tissue analysis, high performance analog and digital computing, optical coherent tomography, microwave photonics, remote sensing (like Lidar), quantum communications and computation, bio-sensing, frequency synthesis and a whole lot more!
— Hi Dan. Years ago, engineers on my team installed an optical repeater on 100 mile optical link, improving the speed capability of the link tenfold (like magic!). That was 15 years ago. Given that optical repeater technology is pretty much essential to long distance fiber communications, are there any changes or improvements on this technology on the horizon?
— Optical repeaters are awesome! The one to keep an eye on today are coherent optical repeaters that can regenerated coherently coded optical data streams, but the whole bank of WDM coherent channels in one amplifier. This technology requires the amplifier to recover phase, and for all channels. But there are good solutions out there in the research front. That is the biggest improvement I see in this technology. The next level is a digital level regenerative optical amplifier and then eventually one that can handle timing too. One other regenerator to look out for are quantum optical repeaters!
— Do you think there is a limit to technological advance, meaning that its evolution will come to a stop one day?
— I dont think so. There is so much we dont understand and keep learning at the scientific level, that I never make assumptions that all is done. Not too long ago statements were made about new technology innovation coming to a halt, then new discoveries made. And the challenge is then to migrate the new discoveries into engineer able solutions. So I think for a good long while we will keep seeing advancements.
Thank you to all who joined us to ‘Ask Dan Anything’! The complete transcript of this discussion has been archived at: The Winnower
Posted: 20 December 2017 by
Rebecca B. Andersen
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