Design and analysis of a CMOS-compatible distributed Bragg reflector laser based on highly uniaxial tensile stressed...

We design a CMOS-compatible Distributed Bragg Reflector (DBR) laser based on highly uniaxial tensile stressed germanium. Our design first incorporates three critical elements including high uniaxial tensile stress, low loss optical resonator and heterojunction for electrical injection. A threshold current density of 80 kA/cm² and an internal quantum efficiency of 8.5% are estimated when the Shockley-Reed-Hall (SRH) lifetime is chosen to be 3 ns. Furthermore, the performance of the DBR laser can be enhanced by improving the crystal quality and carefully designing the p-n junction. The simulation results also indicate that the limitation of the improvement of threshold current density and internal quantum efficiency are 29 kA/cm² and 19.6%, resulting from the Auger recombination. The influences of strain and n-type doping on the threshold current density and the internal quantum efficiency are discussed. The proposed DBR laser offers a new approach to realize on-chip light source for silicon photonics.