Tiny beamsplitter could lead to super fast computing

Chuck Bednar for redOrbit.com – @BednarChuck

Engineers at the University of Utah have developed a system capable of dividing light waves into two separate channels of information, and their work could bring us one step closer to next-generation computers and mobile devices millions of times faster than current technology. Awesome!

Developed by a team led by Utah electrical and computer engineering associate professor Rajesh Menon and described in the journal Nature Photonics, the device is known as an ultracompact beamsplitter. It said to be the smallest unit of its kind created to date.

According to the engineers, this invention could lead to the production of silicon photonic chips that compute and transmit data using light rather than electrons. This would significantly up the speed and power of supercomputers and data center servers, and could ultimately find their way into home computers, smartphones, and tablets, enhancing a multitude of applications.

How the ultracompact beamsplitter works

The device, Menon explained to redOrbit via email, has one input and two outputs, with the two outputs corresponding to the two linear polarization states of light. The beamsplitter is designed to take one or both polarizations of light as an input, and then separate the two polarizations into the two outputs. Other devices have done this, but none have ever been this small.

Menon explained that they input light into their device one polarization at a time and measured the transmission efficiency into the correct output to verify that it performed as expected. This is comparable to separating two channels of communication (such as one video stream from PBS and another from Netflix), he added. Previously, this separation required a lot of time and power-consuming electronics, or the use of photonic devices too large to integrate onto a chip.

“The main challenge for integrated photonics is that the wavelength of light is far larger than the equivalent wavelength of electrons,” the professor told redOrbit. “This is the main reason that devices fundamental to integrated electronics are significantly smaller than those used in integrated photonics. Furthermore, no one had come up with a way to design devices close to this limit for integrated photonics.”

“We solved this problem by first coming up with a new design algorithm and then experimentally verifying that our devices work as intended,” he added. “One crucial advantage of our method is that our fabrication process is completely compatible with the very mature processes already developed for silicon electronics. This means that we can exploit the vast existing manufacturing infra-structure to enable integrated photonics.”

The quest to create a library of ultracompact devices

In the big picture, Menon said, “our research has the potential to maintain Moore’s law for photonics. By enabling integrated photonics devices to be much smaller (in fact, close to their theoretical limits), we allow the integration of more devices in the same area (which increases functionality) and also enable the devices to communicate faster (since they are closer together; light has to travel shorter distances).”

Additionally, by making it possible to include a greater number of devices onto a single chip, their work makes it possible to reduce the cost per chip by exploiting the economies of scale, he told redOrbit. For consumers, this should translate into reduced power consumption and allow for faster communications and computing speeds, while also leading to a reduction in the CO2 emissions partially responsible for global climate change.

“Our vision is to create a library of ultracompact devices (including beamsplitters) that can then be all connected together in a variety of different ways to enable both optical computing and communications,” Menon said, adding that the next step is “to fabricate these in a standard process at a company, and then provide this library of devices to designers and hopefully, unleash their creativity. I believe that these devices will usher in unpredictable, but unbelievably exciting applications.”


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