Built-in germanium lasers could make computer chips faster

The team at the Paul Scherrer Institute (PSI) believe this could revolutionise data streaming within chips and boost the performance of electronics. As the performance of processors has not been able to follow Moore's Law for the past decade, specialists are now talking about Moore's Gap. The researchers say the gap could be closed by optical data transfer between the different cores on the chip. In order to do this though, tiny lasers are needed which can be built into chips to send out light pulses. "Germanium lasers could make a breakthrough possible here, because germanium can be readily combined with silicon, which is the basic material from which chips are made. Silicon itself cannot emit light and can hardly be combined with any available laser material," said PSI scientist Hans Sigg. Using the Swiss Light Source (SLS) at PSI, the researchers investigated the properties of germanium that are important for the generation of laser light, and compared them with those of currently available laser materials. "We stimulate the material by means of a powerful laser and simultaneously observe the changes occurring using infra red radiation from the SLS," said doctoral student Peter Friedli. "To do this, we used the fact that these light pulses are only 100picoseconds long, allowing us to follow the relevant processes in the material; that is, the behaviour of electrons at different points in time." The researchers found that germanium behaves similarly to traditional laser materials. Although it does not yet fulfil the condition for emitting laser light, this condition can be more closely approached the more germanium is put under strain using an external force. The team hope to achieve the necessary conditions in a follow up project.