Using light instead of electrical current to transfer information has been considered to be the best solution for high performance data links. Monolithically integrated lasers on silicon have long been a “holy-grail” for electronic-photonic integration. However, large scale electronic-photonic synergy has been severely limited by material and processing incompatibilities. The monolithic germanium-on-silicon laser described in this paper enables large-scale electronic-photonic integration on silicon for high bandwidth, low energy consumption photonic data links. The potential applications include data centers, servers, as well as multicore microprocessors; including board-to-board, chip-to-chip, core-to-core and core-to-memory interconnections.

Introducing light onto silicon microchips also allows functionalities that cannot be obtained otherwise. Furthermore, since germanium has already been applied to high mobility complementary metal oxide semiconductor (CMOS) transistors, achieving lasing from band-engineered germanium-on-silicon greatly simplifies the processing of electronic-photonic integrated circuits. Compatibility with CMOS technology will allow high yield and low cost manufacturing, and will enable large-scale electronic-photonic synergy for a wide range of applications.