To keep energy consumption under control, future chips may need to move data using light instead of electricity — and the technical expertise to build them may reside in the United States.
Computer chips are one area where the United States still enjoys a significant manufacturing lead over the rest of the world. In 2011, five of the top 10 chipmakers by revenue were U.S. companies, and Intel, the largest of them by a wide margin, has seven manufacturing facilities in the United States, versus only three overseas.
The most recent of those to open, however, is in China, and while that may have been a strategic rather than economic decision — an attempt to gain leverage in the Chinese computer market — both the Chinese and Indian governments have invested heavily in their countries’ chip-making capacities. In order to maintain its manufacturing edge, the United States will need to continue developing new technologies at a torrid pace. And one of those new technologies will almost certainly be an integrated optoelectronic chip — a chip that uses light rather than electricity to move data.
As chips’ computational power increases, they need higher-bandwidth connections — whether between servers in a server farm, between a chip and main memory, or between the individual cores on a single chip. But with electrical connections, increasing bandwidth means increasing power. A 2006 study by Japan's Ministry of Economy, Trade and Industry predicted that by 2025, information technology in Japan alone would consume nearly 250 billion kilowatt-hours worth of electricity per year, or roughly what the entire country of Australia consumes today.
Optoelectronic chips could drastically reduce future computers’ power consumption. But to produce the optoelectronic chips used today in telecommunications networks, chipmakers manufacture optical devices — such as lasers, photodetectors and modulators — separately and then attach them to silicon chips. That approach wouldn’t work with conventional microprocessors, which require a much denser concentration of higher-performance components.
The most intuitive way to add optics to a microprocessor’s electronics would be to build both directly on the same piece of silicon, a technique known as monolithic integration.
In a 2010 paper in the journal Management Science, Erica Fuchs, an assistant professor of engineering and public policy at Carnegie Mellon University, who got her PhD in 2006 from MIT’s Engineering Systems Division, and MIT’s Randolph Kirchain, a principal research scientist at the Materials Systems Laboratory, found that monolithically integrated chips were actually cheaper to produce in the United States than in low-wage countries.
“The designers and the engineers with the capabilities to produce those technologies didn’t want to move to developing East Asia,” Fuchs says. “Those engineers are in the U.S., and that’s where you would need to manufacture.”
During the telecom boom of the late 1990s, Fuchs says, telecommunications companies investigated the possibility of producing monolithically integrated communications chips. But when the bubble burst, they fell back on the less technically demanding process of piecemeal assembly, which was practical overseas. That yielded chips that were cheaper but also much larger.
While large chips are fine in telecommunications systems, they’re not an option in laptops or cellphones. The materials used in today’s optical devices, however, are incompatible with the processes currently used to produce microprocessors, making monolithic integration a stiff challenge.
