Research On Key Technologies Of Long-wavelength Silicon-based Germanium On-chip Light Source

In photonic integration technology at present mainly through bonding groups III-V or epitaxial material on light source to realize the optical coupling and transmission,but these methods due to the high heat resistance between substrate and the light source of the bonding layer and result in poor light heat dissipation can’t compatible with CMOS process limits the mass production,which seriously restrict the development of photonic integration technology.The Vertical Cavity surface Emitting Laser（VCSEL）has the advantages of low threshold current,Cavity length,single longitudinal mode operation and easy large-scale array integration,and has a very broad application prospect in optical communication fields.In this paper the design of Si_xGe_1-x quantum active material and long wavelength light source are studied,the main work is as follows:Firstly,thesis based on PICS3D optical simulation software design and optimize Si_xGe_1-x quantum active material as gain material,the deformation potential theory calculation and analysis of Si_xGe_1-x alloy lattice constant and forbidden band width,calculating the critical thickness Si_xGe_1-x alloy materials and the change of band gap,by defining PICS3D Si_xGe_1-x material layer,the migration model,general properties,external function and alloy energy gap and then design the material gain significant Si_0.13Ge_0.87 quantum active material,for subsequent long wavelength Si Ge VCSEL laying a foundation for design and build of the active region.A silicon based germanium VCSEL with the wavelength of 1550nm is designed on this basis.The DBR,active region and resonant cavity of VCSEL device are calculated theoretically and designed structurally.The DBR used Si/Si O₂ of 1/4 wavelength thickness as high and low refractive index material to compose the upper and lower DBR.It is determined that the upper and lower DBR layers are 5 pairs and 4 pairs respectively.When the central wavelength is 1550nm,the optimal reflectance reaches 99.9%and99.6%,meeting the design requirements.In the active quantum well,Si_xGe_1-x of strain was used as the active quantum well layer,and Si was used as the barrier layer to calculate the band gap and component of the quantum well.By comparing the performance of VCSEL devices with different number of traps,width of traps and doping,it was determined that the active region of the designed 1550nm silicon based germanium VCSEL was 10 layers Si/Si_0.13Ge_0.87 quantum well,the barrier thickness was 15nm,and the trap thickness was 12nm.The thickness and position of the oxide limiting layer were determined by the optical cavity,the resonant cavity mode was analyzed,and finally the structural parameters of the whole VCSEL device were determined.Last the whole simulation was carried out on the VCSEL and analysis,the results show that the designed long wavelength silicon based germanium VCSEL devices working in room temperature temperature of 304K,the threshold current of0.75m A,loss of 29/cm,device gain of 1630/cm,corresponding to the band gap of0.799e V,the output spectrum center wavelength is 1551.9nm,light power is 3.14m W,light field is focused on the active area quantum well area,compared with the traditional III-V VCSEL has the advantages of good performance and compatibility with CMOS technology.