GeSnOI mid-infrared laser technology

摘要

GeSn alloys are promising materials for CMOS-compatible mid-infrared lasers manufacturing.Indeed,Sn alloying and tensile strain can transform them into direct bandgap semiconductors.This growing laser technology however suffers from a number of limitations,such as poor optical confinement,lack of strain,thermal,and defects management,all of which are poorly discussed in the literature.Herein,a specific GeSn-on-insulator(GeSnOI)stack using stressor layers as dielectric optical claddings is demonstrated to be suitable for a monolithically integration of planar Group-IV semiconductor lasers on a versatile photonic platform for the near-and mid-infrared spectral range.Microdisk-shape resonators on mesa structures were fabricated from GeSnOI,after bonding a Ge_(0.9)Sn_(0.1) alloy layer grown on a Ge strain-relaxed-buffer,itself on a Si(001)substrate.The GeSnOI microdisk mesas exhibited significantly improved optical gain as compared to that of conventional suspended microdisk resonators formed from the as-grown layer.We further show enhanced vertical out-coupling of the disk whispering gallery mode in-plane radiation,with up to 30%vertical out-coupling efficiency.As a result,the GeSnOI approach can be a valuable asset in the development of silicon-based mid-infrared photonics that combine integrated sources in a photonic platform with complex lightwave engineering.