Fig. 1. (a) Epitaxial structure of the traditional chip; (b) epitaxial structure of the proposed chip; (c) structure of the DBR laser; (d) gain spectrum

Fig. 2. Mode field distribution for different p-side waveguide thicknesses

Fig. 3. Mode distribution under asymmetric waveguide abtained by FDE. (a) versus Γ; (b) waveguide refractive index, waveguide width versus divergence angle

Fig. 4. (a) The relationship among different waveguide thicknesses and divergence angle and output power; (b) comparison of current density in the horizontal direction at different etching depths

Fig. 5. (a) Refractive index of electron-blocking layer; (b) output power at different components on the EBL

Fig. 6. (a) Light field distribution; (b) energy band diagram of different aluminum components

Fig. 7. Comparison of output power of different structures

Fig. 8. (a) Comparison of output power and (b) electron concentration of different waveguide structures

Fig. 9. Effect of different Al components of ERL on output power and light confinement factor

Fig. 10. Simulated mode distribution for different Al contents. Inset shows their optical confinement factor on p-side and divergence angle

Fig. 11. The refractive index and light field distributed in the transverse direction

Fig. 12. (a) Refractive index distribution of the grating; (b) the relationship between different etching depths and reflectivity