On-chip laser is made entirely from silicon-like elements

An international research team led by Forschungszentrum Jülich (FZJ) has demonstrated the world’s first electrically pumped continuous-wave semiconductor laser made entirely with silicon-like elements. Constructed from stacked layers of silicon-germanium-tin and germanium-tin on top of the silicon base, the device fulfills a long-standing dream of silicon photonics.

Traditionally, light generation in integrated photonics relies on using III-V materials, which are difficult to integrate directly with silicon – although research institute Imec has recently reported a breakthrough in that area. FZJ’s laser takes another approach, using only group IV elements.

Unlike previous germanium-tin lasers that relied on high-energy optical pumping, this new laser operates with a low current injection of just 5 milliamperes at 2 volts, comparable to the energy consumption of a light-emitting diode. The downside is that it does so at an unpractically low temperature of 90 kelvins. However, with the success of earlier optically pumped germanium-tin lasers, which have evolved from cryogenic to room-temperature operation in only a few years, the researchers see a clear path forward.