Fig. 1. Diagram of three LDs’ epitaxial structures

Fig. 2. (a) Refractive index and TE mode optic field intensity distributions of three LDs; (b) magnified diagrams in the range of 1750−1900 nm for LD1, LD2, and LD3

Fig. 3. Curves of (a) quantum well external loss (α_Out), (b) quantum well internal loss (α_QW), and (c) total optical loss (α_Total) of three LDs as a function of injection current

Fig. 4. (a) The energy band comparison of the LDs with three structures at an injection current of 10 A and (b) the magnification of LD1, LD2, and LD3 in the 1760−1860 nm range

Fig. 5. (a) Leakage current density, (b) auger recombination current density, (c) SRH recombination current density, and (d) nonradiative recombination current density of three LDs as a function of injection current

Fig. 6. (a) Threshold current of three LDs; (b) operating voltage, (c) output power and (d) WPE of three LDs as a function of injection current

Fig. 7. (a) Fitted curves of wavelength and (b) threshold current of three LDs as a function of temperature