For the first time, researchers of the University of Twente succeeded in connecting two parts of an electronics chip using an on-chip optical link. A light connection can, for example, be a safe way of connecting high-power electronics and digital control circuitry on one chip, without a direct electrical link. Until now, however, an optical link was not possible using standard silicon chip technology. Vishal Agarwal, a UT PhD student, managed to do so. He realized a very small optocoupler circuit that delivers a data rate of Megabits per second in an energy-efficient way.
Using light, it is possible to isolate one part of a chip of another: the two different worlds will be able to communicate, but there is no electrical connection. In ‘smart power’ chips, the high-power part can be isolated from the digital control circuits. This isolation guarantees safe operation in application areas like medical electronics and automotive. A so-called ‘optocoupler’ is used for this, but until now, this is a bulky device, separated from the actual chip. The dream, having an on-chip optocoupler, has now been realized by Vishal Agarwal. His optocoupler can be integrated with the electronics using standard chip technology (CMOS). It is about 0,008 square millimeter in size and consumes minimal energy.