The internet of tomorrow could be about 100 times faster than it is today by using the power of light instead of electricity to move data. The secret lies in knowing when to use light, when to stick with traditional electronics, and how to combine the two when needed.
There has been a great deal of talk recently about an all-optical (light-using) computer or internet, but this is misleading. What is really needed, as U of T Professor of Electrical and Computer Engineering Ted Sargent explains, is a hybrid of optics and electronics. The switch is a perfect example. The switch controlling signal flow is the slowest element of any network because incoming light must be converted to an electronic signal before being processed by the switch, and then reconverted back to light after exiting the switch.
The switching mechanism, however, involves both the decision to activate a switch and the actual switching. The switching itself can be done using an ultra-fast, all-optical device. The information processing and decision-making leading to throwing the switch, however, is a complex process best handled by traditional electronics. If the decision-making begins in advance of the data stream arriving at the switch, it will not impede the overall process.
“The control of switches using electronics is only convenient if you can integrate optics and electronics,” explains Sargent. His research involves the creation of hybrid materials that incorporate both electricity and light. Another area of research, and one that has attracted a great deal of press, concerns maximizing the efficiency of the all-optical components themselves.
Light-using switches rely on the fact that the way some materials react to light is changed after they have been struck by light. Ultimately, light can be used to control light, and one laser beam can direct the path of a second. If the second laser is carrying telecommunication fibre optics, data can be routed with unprecedented control.
“Buckyballs” are soccer ball-shaped molecules made of 60 carbon atoms that have incredible properties–most notable of which is their huge electrical potential. Washington State University theoretical physicist Mark Kuzyk showed that the strength of their electrical behaviour was only a fraction of their potential. This discrepancy is called the “Kuzyk quantum gap.” Sargent, along with organic chemist Wayne Wang at Carleton University has been able to improve this substantially and bring buckyballs closer to realizing their potential.
The solution again came in the form of a hybrid. The research group discovered that connecting and cross-linking chains of molecules on the surface of the buckyballs allows for huge amounts of electricity to be harnessed when light strikes them. The more electricity that can be controlled, the greater the response of a given material to light, and the better one stream of light can control another. In the case of the buckyball-chain hybrid, they “use every electron in the system to max effect,” explains Sargent.
While Sargent believes his research is done in the true spirit of nanotechnology, he is quick to add that there is much more work to be done. The primary vision of nanotechnology, in his view, is as a means of “linking ‘top down’ and ‘bottom up’ approaches. And what I mean by ‘top down’ is linking human needs and by ‘bottom up’ I mean how molecules become material.” The idea is to unite the underlying physics of matter with its function in the world.
With research in light and nanotechnology proving to be a scientific revolution, bringing the technology to business is the next logical step. While on sabbatical at the Massachusetts Institute of Technology (MIT), Sargent is teaching a seminar called “Fostering Nanotechnology Innovation within the Large Technology-Driven Organization” with Rebecca Henderson, a Professor at the MIT Sloan School of Management. The seminar focuses on ways in which interdisciplinary research can be put towards creating products and services in a consumer economy.
